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Sample records for reaktore wwr-sm inp

  1. Control Rod Ejection Accident while Using 6- and 8-Tube IRT-4M Fuel Assemblies in WWR-SM Research Reactor Core

    Energy Technology Data Exchange (ETDEWEB)

    Baytelesov, S.; Kungurov, F.; Safarov, A.; Salikhbaev, U.

    2011-07-01

    The WWR-SM reactor at the Institute of Nuclear Physics of the Academy of Sciences (INP AS) in Uzbekistan was converted to 6-tube IRT-4M LEU (19.7%) fuel in 2009. Presently, INP intends to also use IRT-4M 8-tube FA, and a safety analysis for these 'mixed' (8-tube and 6-tube FA) cores is required by the regulatory authorities. This paper presents results of control rod ejection transient analysis for these mixed cores

  2. A neutronic feasibility study for LEU conversion of the WWR-SM research reactor in Uzbekistan.

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    Rakhmanov, A.

    1998-10-19

    The WWR-SM research reactor in Uzbekistan has operated at 10 MW since 1979, using Russian-supplied IRT-3M fuel assemblies containing 90% enriched uranium. Burnup tests of three full-sized IRT-3M FA with 36% enrichment were successfully completed to a burn up of about {approximately}50% in 1987-1989. In August 1998, four IRT-3M FA with 36% enriched uranium were loaded into the core to initiate conversion of the entire core to 36% enriched fuel. This paper presents the results of equilibrium fuel cycle comparisons of the reactor using HEU (90%) and HEU (36%) IRT-3M fuel and compares results with the performance of IRT-4M FA containing LEU (19.75%). The results show that an LEU (19.75%) density of 3.8 g/cm{sup 3} is required to match the cycle length of the HEU (90%) core and an LEU density 3.9 g/cm{sup 3} is needed to match the cycle length of the HEU (36%) core.

  3. ANALISIS KECELAKAAN REAKTOR AKIBAT KEGAGALAN SISTEM PEMBUANG PANAS PADA REAKTOR NUKLIR GENERASI IV

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    A. G. Abdullah

    2012-05-01

    Full Text Available Salah satu aspek terpenting dalam proses desain reaktor nuklir adalah aspek keselamatan reaktor. Sebelum membangun reaktor secara fisik, terlebih dahulu dibuat perencaaan perhitungan yang matang termasuk melakukan simulasi kinerja keselamatannya dalam menghadapi kemungkinan kecelakaan. Penelitian ini bertujuan untuk mengembangkan model simulasi kecelakaan Pembangkit Listrik Tenaga Nuklir (PLTN yang disebabkan  gagalnya sistem pembuang panas. Kecelakaan akibat gagalnya sistem pembuang panas dipicu oleh hilangnya kemampuan pendinginan dari pembangkit uap. Urutan kecelakaan ini diawali dengan hilangnya kemampuan reaktor untuk membuang panas dari loop pendingin sekunder. Selama kecelakaan, laju pembuangan panas mengalami penurunan sedangkan temperatur masukan pendingin mengalami peningkatan. Hasil simulasi memberikan gambaran bahwa reaktor dapat bertahan dari kecelakaan. Hasil analisis kecelakaan menunjukkan bahwa temperatur maksimum bahan bakar, selongsong dan pendingin memiliki batas keselamatan yang sangat besar.One of the most important aspects in nuclear reactor design process is the safety aspect. Advanced and accurate safety simulation must be performed before it can be built.  This research aims to develop a simulation model of Nuclear Power Plant (NPP accidents due to the loss of  heat sink system. Loss of heat sink accident was triggered by the loss of cooling capability of steam generators.  This  accident  sequence  began with the loss of the reactor’s ability to remove heat from the secondary cooling loop. During the accident, the heat dissipation rate decreased whereas the coolant inlet temperatures increased till a new equilibrium level. The analysis results of the accident showed that there are large safety margin to the maximum temperature of the fuel, cladding, and coolant.

  4. DESAIN KONSEPTUAL PERISAI RADIASI REAKTOR RRI-50

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    Amir Hamzah

    2015-06-01

    Full Text Available ABSTRAK DESAIN KONSEPTUAL PERISAI RADIASI REAKTOR RRI-50. Salah satu parameter yang harus dipenuhi dalam mendesain reaktor nuklir adalah desain perisai radiasi yang dapat menjamin keamanan dan keselamatan radiasi bagi pekerja dan masyarakat sekitar. Pada penelitian ini dilakukan desain perisai radiasi RRI-50 dengan elemen bakar berjenis U9Mo-Al berkerapatan tinggi dengan tipe pelat sebanyak 21 buah dan berdimensi seperti elemen bakar RSG-GAS tapi panjang aktifnya 70 cm. Konfigurasi teras terdiri dari 16 elemen bakar dan 4 elemen kendali serta 5 posisi iradiasi sehingga membentuk matriks 5 x 5. Tujuan dari penelitian ini adalah mendesain perisai radiasi dan menentukan distribusi laju dosis di daerah kerja dan di lingkungan reaktor RRI-50. Tahapan awal penelitian adalah perhitungan kuat sumber dan inventori bahan radioaktif teras reaktor dengan mensimulasikan operasi 50 MW selama 20 hari tiap siklus menggunakan program ORGEN2.1. Berdasarkan kuat sumber tersebut dan model yang dibuat menggunakan program VisEd, maka dilakukan analisis penentuan parameter perisai radiasi secara iteratif menggunakan program MCNPX. Pada tahap akhir, dilakukan analisis distribusi laju dosis di seluruh ruang di dalam dan di luar gedung reaktor juga menggunakan program MCNPX. Hasil yang diperoleh menunjukkan bahwa ketinggian permukaan air adalah 1000 cm dan kombinasi 90 cm beton berat dan 60 cm beton biasa dapat digunakan sebagai perisai biologi. Desain perisai tersebut mereduksi laju dosis menjadi 0,05 µSv/jam di Balai Operasi sementara di Balai Eksperimen dan di luar gedung reaktor menjadi 4,2 µSv/jam dan 0,03 µSv/jam pada saat reaktor beroperasi. Hasil penelitian juga menunjukkan pemasagan perisai tambahan setebal 280 cm berjarak 300 cm di depan tabung berkas neutron radial yang terbuka mereduksi laju dosis gamma dan neutron menjadi 3,3 µSv/jam dan 3,1x10-11 µSv/jam. Hasil-hasil penelitian ini menunjukkan bahwa desain perisai radiasi yang dibuat membuat reaktor

  5. REAKTOR INNOVATIVE MOLTEN SALT (IMSR DENGAN SISTEM KESELAMATAN PASIF MENYELURUH

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    Andang Widiharto

    2015-04-01

    Full Text Available Pengembangan Teknologi Reaktor Nuklir pada masa mendatang mengarah pada peningkatan aspek keselamatan, peningkatan pendayagunaan bahan bakar, reduksi limbah radioaktif, ketahanan terhadap proliferasi bahan-bakar nuklir dan peningkatan aspek ekonomi. reaktor Innovative Molten Salt (IMSR adalah reaktor nuklir yang menggunakan bahan bakar cair berupa garam lebur fluoride (7LiF-ThF4-UF4-MaFx. Reaktor IMSR didesain sebagai reaktor pembiak termal, yaitu membiakkan U-233 dari Th-232. Hal ini untuk menjawab permasalahan sustainabilitas ketersedian sumber daya bahan bakar nuklir dan reduksi limbah radioaktif. Dalam aspek keselamatan, desain reaktor IMSR memiliki sifat inherent safe, yaitu koefisien umpan balik daya yang negatif serta memiliki fitur-fitur keselamatan pasif. Fitur-fitur keselamatan pasif terdiri dari sistem shutdown pasif, sistem pendinginan pasif pasca shutdown serta sistem pendinginan pasif untuk produk fisi. Kecelakaan yang berpotensi terjadi pada IMSR, yaitu kecelakaan kehilangan aliran bahan bakar, kecelakaan kehilangan aliran pendingin, kecelakaan kehilangan kemampuan pengambilan kalor serta kecelakaan kerusakan integritas sistem reaktor, dapat ditangani sepenuhnya secara pasif hingga mencapai kondisi shutdown selamat. Kata kunci: keselamatan pasif, inherent safe, IMSR   The next Nuclear Reactor Technology developments are directed to the increasing of the aspects of safety, fuel utility, radioactive waste reduction, proliferation retention and economy. Innovative Molten Salt Reactor (IMSR is a nuclear reactor design that uses fluoride molten salt (7LiF-ThF4-UF4-MaFx. IMSR is designed as a thermal breeder reactor, i.e. to produce U-233 from Th-232. This is the answer of natural nuclear fuel sustainability and radioactive waste problems. In term of safety aspect, IMSR design has inherent safe characteristics, i.e. negative power feedback coefficient, and passive safety features. The passive safety features are passive shutdown

  6. ANALISIS PENGENDALIAN DAYA REAKTOR PCMSR DENGAN LAJU ALIR PENDINGIN

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    Iqbal Syafin Noha

    2015-03-01

    Full Text Available Passive Compact Molten Salt Reactor (PCMSR merupakan pengembangan dari Molten Salt Reactor (MSR yang memiliki karakter berbeda dengan lima reaktor generasi IV lainnya, yaitu menggunakan bahan bakar leburan garam. Pada reaktor MSR, garam lebur tidak digunakan sebagai pendingin tetapi digunakan sebagai medium pembawa bahan bakar. Dengan fase bahan bakar yang berupa garam lebur LiF-BeF2-ThF4-UF4, maka dapat dilakukan pengendalian daya dengan mengatur laju aliran bahan bakar dan pendingin. Tujuan penelitian ini adalah untuk mengetahui pengaruh perubahan laju alir pendingin terhadap daya reaktor PCMSR. Analisis dilakukan dengan empat jenis masukan untuk perubahan laju alir pendingin, yaitu masukan step, ramp, eksponensial, dan sinusoidal. Untuk masukan step, laju alir pendingin dibuat berubah secara mendadak. Selanjutnya untuk masukan ramp dan eksponensal, perubahan laju alir masing-masing dibuat perlahan secara linear dan mengikuti fungsi eksponensial. Kemudian untuk masukan sinusoidal, laju alir berubah naik turun secara periodik dengan memvariasikan frekuensi dari perubahan laju alir tersebut. Hasil penelitian menunjukkan bahwa penurunan laju alir pendingin sebesar 50% dari laju pendingin sebelumnya, menyebabkan daya pada reaktor PCMSR turun sebesar 63% dari daya sebelumnya. Jika terjadi fluktuasi laju aliran pendingin, maka semakin cepat perubahan tersebut, maka respon daya yang diberikan semakin kecil. Pada frekuensi yang sangat cepat, daya reaktor menjadi konstan dan cenderung tidak memiliki respon terhadap laju aliran. Hal ini merupakan salah satu aspek keselamatan reaktor, karena reaktor tidak merespon perubahan yang terlalu cepat. Kemampuan reaktor mengatur daya menyesuaikan laju aliran pendingin merupakan aspek keselamatan lainnya. Kata kunci : PCMSR, pengendalian daya, laju alir pendingin, uji respon   Passive Compact Molten Salt Reactor (PCMSR is the development of Molten Salt Reactor (MSR which has different character from other five

  7. PENGARUH DAYA DAN DURASI OPERASI REAKTOR TERHADAP KONSENTRASI 3H DAN 14C DI AIR SISTEM PENDINGIN PRIMER REAKTOR RSG-GAS

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    Pande Made Udiyani

    2015-03-01

    Full Text Available Telah dilakukan penelitian terhadap pengaruh daya dan durasi operasi reaktor terhadap konsentrasi 3H dan 14C dalam air sistem pendingin primer reaktor RSG-GAS. Keberadaan nuklida 3H dan 14C di dalam air sistem pendingin primer reaktor RSG-GAS merupakan hasil produk fisi dan aktivasi. Nuklida radioaktif ini mempunyai potensi bahaya radiasi interna dan eksterna, karena mempunyai umur paro yang panjang yaitu 12,26 tahun untuk 3H dan 5568 tahun untuk 14C, sehingga mempunyai dampak radiologis yang sangat berarti. Analisis dan pengukuran contoh cuplikan air pendingin primer dilakukan dengan menggunakan alat LSC (Liquid Scintillation Counter. Tujuan dari penelitian ini adalah mengetahui pengaruh daya dan durasi operasi reaktor terhadap konsentrasi nuklida 3H dan 14C dalam air sistem pendingin primer, korelasi konsentrasi kedua nuklida dengan komponen sistem reaktor yang berkaitan dengan penuaan komponen, dan estimasi penerimaan radiasi terhadap pekerja radiasi di reaktor RSG-GAS dalam kaitan dengan keselamatan daerah kerja dan keselamatan personil. Hasil penelitian menunjukkan bahwa besarnya konsentrasi 3H dan 14C di air sistem pendingin primer reaktor RSG-GAS sebanding dengan daya yang dibangkitkan dan durasi operasi reaktor. Pertambahan konsentrasi 3H dan 14C di kolam reaktor RSG-GAS yang pesat setelah lima tahun pertama operasi reaktor diperkirakan karena intensitas pengoperasian reaktor yang tinggi, dan adanya proses akumulasi nuklida yang mempunyai umur paro yang panjang. Hasil penelitian ini dapat dimanfaatkan untuk mengkaji keselamatan operasi reaktor, keselamatan personil, keselamatan kerja, dan proses penuaan reaktor. Kata kunci : air pendingin primer, 3H, 14C, reaktor RSG-GAS   The influence of reactor power and operation duration on concentration of 3H and 14C in primary coolant water system RSG-GAS reactor has been studied. The existence of nuclides 3H and 14C in primary coolant system RSG-GAS reactor is a result of fission product and

  8. Fire modeling of the Heiss Dampf Reaktor containment

    Energy Technology Data Exchange (ETDEWEB)

    Nicolette, V.F. [Sandia National Labs., Albuquerque, NM (United States); Yang, K.T. [Notre Dame Univ., IN (United States)

    1995-09-01

    This report summarizes Sandia National Laboratories` participation in the fire modeling activities for the German Heiss Dampf Reaktor (HDR) containment building, under the sponsorship of the United States Nuclear Regulatory Commission. The purpose of this report is twofold: (1) to summarize Sandia`s participation in the HDR fire modeling efforts and (2) to summarize the results of the international fire modeling community involved in modeling the HDR fire tests. Additional comments, on the state of fire modeling and trends in the international fire modeling community are also included. It is noted that, although the trend internationally in fire modeling is toward the development of the more complex fire field models, each type of fire model has something to contribute to the understanding of fires in nuclear power plants.

  9. Startup Reaktor Cepat berpendingin Gas Berbahan Bakar UN-PuN dengan Daya 800 MWth

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    Tri Siswandi Syahputra

    2017-05-01

    Full Text Available Studi strategi startup reaktor cepat berpendingin helium dengan bahan bakar uranium alam dan campuran plutonium dari PWR telah dilakukan. Reaktor dengan keluaran daya menengah dioperasikan dengan pengisian ulang bahan bakar setiap 10 tahun selama 40 tahun beroperasi. Perhitungan dilakukan dengan menggunakan sistem pengkodean SRAC dan JENDL -33 library, dengan model teras cylindrical cell 2D R-Z. Reaktor didesain dengan strategi stratup pembakaran CANDLE (Constan Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy producing reactor yang dimodifikasi dalam keadaan non equilibrium state. Dalam skema ini, teras aktif dibagi menjadi region-1 sampai dengan region-10 arah aksial dengan volume yang sama dan 2 region arah radial dengan fuel fraction berbeda. Bahan bakar fresh Uranium alam awalnya dimasukkan ke dalam region- 1, sedangkan region lainnya diisi oleh campuran uranium alam dan spent fuel dari PWR. Setelah satu siklus operasi, dilakukan pergeseran region-1 ke region-2, region-2 ke region -3 dan seterusnya. Bahan bakar pada region -10 dibuang sedangkan region-1 akan diisi kembali oleh bahan bakar Uranium alam. Ukuran daya reaktor 800 MWth dengan variasi fraksi bahan bakar telah diselidiki. Perhitungan dilakukan terhadap desain teras reaktor yang menggunakan variasi fraksi bahan bakar di bagian dalam dan luar : 50%,55%; 55%,60%, dan 60%,65%. Reaktor dengan daya 800 MWth dengan fraksi bahan bakar 50,55% menunjukan desain yang optimal. Rasio antara puncak dengan daya rata-rata diperoleh nilai 1.57 arah radial dan 2.57 arah aksial.

  10. INVESTIGASI KARAKTERISTIK TERMOHIDROLIKA TERAS REAKTOR DAYA KECIL DENGAN PENDINGINAN SIRKULASI ALAM MENGGUNAKAN RELAP5

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    Susyadi Susyadi

    2016-02-01

    Full Text Available ABSTRAK INVESTIGASI KARAKTERISTIK TERMOHIDROLIKA TERAS REAKTOR DAYA KECIL DENGAN PENDINGINAN SIRKULASI ALAM MENGGUNAKAN RELAP5. Reaktor modular daya-kecil (small modular reactor, SMR memiliki prospek tinggi untuk dibangun di Indonesia. Keluaran dayanya yang relatif kecil dan disainnya yang kompak serta dapat dikonstruksi secara modular memberikan keunggulan fleksibilitas pembangunan yang lebih baik dibanding reaktor konvensional berdaya besar. Disain sistem reaktor kategori ini sangat bervariasi, salah satu diantaranya adalah jenis reaktor air tekan (pressurized water reactor, PWR yang menerapkan sirkulasi alamiah pada sistem pendingin primernya. Selain itu reaktor ini juga memiliki teras (core lebih pendek dibanding PWR konvensional. Dari kedua perbedaan tersebut maka terdapat kemungkinan perbedaan pola perpindahan panas yang dapat berimplikasi terhadap keselamatan secara keseluruhan. Oleh karena itu, pada penelitian ini dilakukan investigasi terhadap karakteristik termohidrolika teras reaktor tersebut khususnya karakteristik temperatur fluida dan bahan bakar serta laju alir fluidanya. Tujuannya adalah untuk mengetahui perbedaan marjin keselamatan temperatur teras reaktor bila dibanding dengan PWR konvensional. Investigasi dilakukan dengan menggunakan program RELAP5, dimana secara parsial teras reaktor dimodelkan menggunakan model-model generik yang ada pada program dan dilakukan beberapa perhitungan kondisi tunak. Hasil perhitungan menunjukkan bahwa saat beroperasi pada daya nominalnya, reaktor modular ini memiliki margin temperatur pendidihan sebesar 2K lebih baik dibanding reaktor konvensional. Selain itu, keunggulan marjin keselamatan reaktor modular daya-kecil ini juga ditunjukkan dari naiknya laju alir mengikuti kenaikan dayanya yang berarti memiliki sifat keselamatan yang melekat (inherent safety. Kata kunci: reaktor modular daya-kecil, PWR, sirkulasi alam, RELAP5, termohidrolika   ABSTRACT INVESTIGATION ON CORE THERMAL HYDRAULIC

  11. OPTIMASI DESAIN TERMOHIDROLIKA TERAS DAN SISTEM PENDINGIN REAKTOR RISET INOVATIF DAYA TINGGI

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    Endiah Puji Hastuti

    2015-10-01

    Full Text Available ABSTRAK OPTIMASI DESAIN TERMOHIDROLIKA TERAS DAN SISTEM PENDINGIN REAKTOR RISET INOVATIF DAYA TINGGI. Implementasi reaktor inovasi telah diterapkan pada berbagai reaktor riset baru yang saat ini sedang dibangun.  Pada saat ini BATAN sedang merancang desain konseptual reaktor riset daya tinggi yang telah masuk pada tahap optimasi desain. Spesifikasi desain konseptual reaktor riset inovatif adalah reaktor tipe kolam berpendingin air dan reflektor D2O. Teras reaktor memiliki kisi 5x5 dengan 16 bahan bakar dan 4 batang kendali. Teras reaktor berada di dalam tabung berisi D2O yang berfungsi sebagai posisi iradiasi. Daya reaktor 50 MW didesain untuk membangkitkan fluks neutron termal sebesar 5x1014 n/cm2s. Teras reaktor berbentuk kompak dan menggunakan bahan bakar U9Mo-Al dengan tingkat muat uranium 7-9 gU/cm3. Desain termohidrolika yang mencakup pemodelan, perhitungan dan analisis kecukupan pendingin dibuat sinergi dengan desain fisika teras agar keselamatan reaktor terjamin. Makalah ini bertujuan menyampaikan hasil analisis perhitungan termohidrolika teras dan sistem reaktor riset inovatif pada kondisi tunak. Analisis dilakukan menggunakan program perhitungan yang telah tervalidasi, masing-masing adalah Caudvap, PARET-ANL, Fluent dan ChemCad 6.4.1. Hasil perhitungan menunjukkan bahwa pembangkitan panas yang tinggi dapat dipindahkan tanpa menyebabkan pendidihan dengan menerapkan desain teras reaktor bertekanan, di samping itu desain awal komponen utama sistem pembuangan panas yang terintegrasi telah dilakukan, sehingga konseptual desain termohidrolika RRI-50 dapat diselesaikan. Kata kunci : reaktor riset inovatif, Caudvap, PARET-ANL, Fluent, ChemCad 6.4.1.   ABSTRACT THERMALHYDRAULIC DESIGN AND COOLING SYSTEM OPTIMIZATION OF THE HIGH POWER INOVATIVE RESEARCH REACTOR. Reactor innovation has been implemented in a variety of new research reactors that currently are being built. At this time BATAN is designing a conceptual design of the high power

  12. DESAIN KONSEPTUAL TERAS REAKTOR RISET INOVATIF BERBAHAN BAKAR URANIUM MOLIBDENUM DARI ASPEK NEUTRONIK

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    Tukiran Surbakti

    2015-03-01

    Full Text Available Manfaat yang luas dari penggunaan reaktor riset membuat banyak negara membangun reaktor riset baru. Kecenderungan saat ini adalah reaktor tipe reaktor serbaguna (MPR dengan teras yang kompak untuk mendapatkan fluks neutron yang tinggi dengan daya yang relatif sedang atau rendah. Reaktor riset yang ada di Indonesia yang paling muda usianya sudah berumur 25 tahun. Oleh karena itu diperlukan desain reaktor riset baru sebagai alternatif, disebut reaktor riset inovatif (RRI, kelak pengganti reaktor riset yang sudah ada. Tujuan dari riset ini mendapatkan konfigurasi teras setimbang reaktor riset yang optimal dengan kriteria memiliki fluks neutron termal minimum sebesar 2,5x1014 n/cm2 s pada daya 20 MW (minimum, memiliki panjang operasi satu siklus lebih dari 40 hari dan penggunaan bahan bakar yang paling efisien. Desain neutronik dilakukan untuk bahan bakar baru U-9Mo-Al dengan kerapatan bervariasi dan jenis reflektor yang bervariasi. Desain dilakukan dengan paket program WIMSD-5B dan BATAN-FUEL. Hasil desain konseptual menyajikan 4 konfigurasi teras yaitu 5×5, 5×7, 6×5 dan 6×6. Hasil optimasi menunjukkan bahwa teras setimbang reaktor RRI dengan konfigurasi 5×5, tingkat muat 235U sebesar 450 g, reflektor berilium, fluks neutron termal maksimum di daerah reflektor sebesar 3,33×1014 neutron cm-2s-1 dan panjang siklus 57 hari merupakan desain teras reaktor riset inovatif yang paling optimal. Kata kunci: desain konseptual, bahan bakar uranium-molibdenum,berilium, D2O, WIMS, BATAN-FUEL   The multipurpose of research reactor utilization make many countries build the new research reactor. Trend of this reactor for this moment is multipurpose reactor type with a compact core to get high neutron flux at the low or medium level of power. The research newest reactor in Indonesia right now is already 25 year old. Therefore, it is needed to design a new research reactor, called innovative research reactor (IRR and then as an alternative to replace the old

  13. DESAIN TERAS ALTERNATIF UNTUK REAKTOR RISET INOVATIF (RRI DARI ASPEK NEUTRONIK

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    Iman Kuntoro

    2015-03-01

    Full Text Available Berdasarkan dokumen kriteria pengguna dan fungsi utamanya, Reaktor Riset Inovatif (RRI dipersyaratkan dapat menghasilkan fluks neutron termal maksimum 1×1015 neutron cm-2s-1. Hal ini diperlukan agar reaktor RRI dapat digunakan untuk target yang membutuhkan fluks neutron tinggi. Dalam penelitian sebelumnya diperoleh bahwa desain reaktor RRI tidak mungkin menghasilkan fluks neutron tersebut jika menggunakan bahan bakar seperti yang digunakan reaktor RSG-GAS. Hal ini diduga karena dimensinya terlalu besar, mengingat fluks neutron berbanding terbalik dengan volume teras. Tujuan penelitaian ini adalah untuk mendapatkan desain teras alternatif reaktor RRI yang memenuhi persyaratan fluks neutron termal tersebut. Alternatif bahan bakar yang dipilih adalah yang dipakai di reaktor JMTR (Japan Material Testing Reactor yang berdimensi lebih kecil dibanding reaktor RSG-GAS. Disamping itu tinggi aktif teras divariasi 70 cm dan 75 cm. Desain teras dilakukan dengan perangkat analaitik WIMS-D5B, Batan-FUEL dan Batan-3DIFF. Teras alternatif menggunakan konsep konfigurasi teras kompak 5×5 dengan 4 elemen kendali jenis follower. Berdasarkan hasil perhitungan ada 3 (tiga teras alternatif yang dapat memenuhi persyaratan tersebut, termasuk teras menggunakan bahan bakar reaktor RSG-GAS dengan menambah tinggi aktifnya menjadi 70 cm dari 60 cm. Dengan menganalisis seluruh aspek, keselamatan serta efisiensi dan efektivitas reaktor, maka teras alternatif dengan bahan bakar tipe JMTR dengan tinggi aktif 70 cm merupakan teras alternatif yang terbaik. Kata kunci: neutronik, teras kompak, reaktor riset inovatif, fluks neutron termal tinggi   Based on its User Requirement Document and main function, RRI shall be able to provide a maximum thermal neutron flux of 1×1015 neutron cm-2s-1. The reason is that the RRI reactor can serve targets requiring a high neutron flux. From the previous results it was obtained that RRI design using fuel of RSG-GAS type was not possible to

  14. PENINGKATAN KINERJA SISTEM KESELAMATAN PASIF PADA REAKTOR NUKLIR DENGAN PENAMBAHAN KOMPONEN RVACS

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    A. G. Abdullah

    2014-07-01

    Full Text Available Kelengkapan sistem keselamatan pasif dan inheren pada reaktor lanjut merupakan prasyarat utama. Makalah ini mengeksplorasi hasil desain konseptual sistem pembuang sisa panas pada pusat listrik tenaga nuklir berjenis Very High-Temperature Reactor. Tujuan riset ini untuk merancang sistem pembuang sisa panas pusat listrik tenaga nuklir yang terdapat pada dinding reaktor. Studi kinerja Reactor Vessel Auxliary Cooling System (RVACS dilakukan pada dua jenis pendingin yaitu Timbal-Bismut dan Liquid Salt. Panas dari dinding reaktor dihapus melalui sirkulasi alamiah pada keadaan tunak. Analisis melibatkan sistem perpindahan panas secara radiasi, konduksi dan konveksi alami. Perhitungan perpindahan panas dilakukan pada elemen reaktor vessel, dinding luar guard vessel, dan pelat pemisah. Hasil analisis kecelakaan menunjukkan kedua jenis sistem pendingin reaktor dan sistem pasif sisa pembuangan panas cukup menghapus sisa panas hasil peluruhan dengan sirkulasi alami.ABSTRACTCompleteness of passive safety systems and inherent in advanced reactors is a major prerequisite. This paper explores the results of a conceptual design of the heat removal system at the nuclear power plant (NPP type Very High-Temperature Reactor. The purpose of this research was to design the reactor vessel auxiliary cooling system (RVACS of NPP located within the reactor walls. The RVACS performance study was conducted on two types of coolant: Lead-Bismuth and Liquid Salt. Heat was removed from the reactor vessel through the natural circulation in the steady state. Analyses of heat transfer systems involved radiation, conduction and natural convection. Heat transfer calculations were performed on the reactor vessel, guard vessel, and perforated plate. The results from the accident analysis showed that both types, the reactor coolant system and the passive residual heat removal system, adequately remove remaining heat of the decay by a natural circulation.

  15. PENINGKATAN KINERJA SISTEM KESELAMATAN PASIF PADA REAKTOR NUKLIR DENGAN PENAMBAHAN KOMPONEN RVACS

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    A. G. Abdullah

    2014-07-01

    Full Text Available Kelengkapan sistem keselamatan pasif dan inheren pada reaktor lanjut merupakan prasyarat utama. Makalah ini mengeksplorasi hasil desain konseptual sistem pembuang sisa panas pada pusat listrik tenaga nuklir berjenis Very High-Temperature Reactor. Tujuan riset ini untuk merancang sistem pembuang sisa panas pusat listrik tenaga nuklir yang terdapat pada dinding reaktor. Studi kinerja Reactor Vessel Auxliary Cooling System (RVACS dilakukan pada dua jenis pendingin yaitu Timbal-Bismut dan Liquid Salt. Panas dari dinding reaktor dihapus melalui sirkulasi alamiah pada keadaan tunak. Analisis melibatkan sistem perpindahan panas secara radiasi, konduksi dan konveksi alami. Perhitungan perpindahan panas dilakukan pada elemen reaktor vessel, dinding luar guard vessel, dan pelat pemisah. Hasil analisis kecelakaan menunjukkan kedua jenis sistem pendingin reaktor dan sistem pasif sisa pembuangan panas cukup menghapus sisa panas hasil peluruhan dengan sirkulasi alami.ABSTRACTCompleteness of passive safety systems and inherent in advanced reactors is a major prerequisite. This paper explores the results of a conceptual design of the heat removal system at the nuclear power plant (NPP type Very High-Temperature Reactor. The purpose of this research was to design the reactor vessel auxiliary cooling system (RVACS of NPP located within the reactor walls. The RVACS performance study was conducted on two types of coolant: Lead-Bismuth and Liquid Salt. Heat was removed from the reactor vessel through the natural circulation in the steady state. Analyses of heat transfer systems involved radiation, conduction and natural convection. Heat transfer calculations were performed on the reactor vessel, guard vessel, and perforated plate. The results from the accident analysis showed that both types, the reactor coolant system and the passive residual heat removal system, adequately remove remaining heat of the decay by a natural circulation.

  16. PENGARUH PROSES PENGINTEGRASIAN PANAS TERHADAP KONVERSI AMONIAK PADA INTERCOOLER REAKTOR AMONIAK DENGAN ANALISIS EKSERGI DAN PINCH

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    Muhammad Djoni Bustan

    2012-02-01

    Full Text Available Amoniak merupakan salah satu senyawa penting yang banyak digunakan dalam industri kimia sebagai bahan baku dan produk. Salah satu unit pabrik amoniak yang dikaji membutuhkan gas alam sebesar 13.627 MMBTU sebagai bahan bakar (fuel dan 24.570 MMBTU sebagai bahan baku untuk memproduksi 1 ton amoniak cair. Belum optimalnya sistim pendinginan antar unggun (bed dan belum maksimalnya pemanfaatan panas hasil reaksi di reaktor amoniak menyebabkan konversi reaksi masih rendah. Analisis eksergi yang merupakan kombinasi antara Hukum Termodinamika I dan II,  digunakan untuk mengetahui titik- titik kehilangan panas yang paling tinggi, yaitu pada bed 1, bed 2, dan bed 3. Analisis pinch yang diterapkan pada reaktor tersebut dapat dibuat suatu sistem jaringan alat penukar panas yang baru pada ammonia converter, sehingga diperoleh konversi yang lebih baik.

  17. Pengembangan Reaktor Fotokatalitik Rotating Drum untuk Pengolahan Air Limbah Industri Tekstil

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    Cholid Syahroni

    2015-11-01

    Full Text Available Reaksi oksidasi fotokatalitik memiliki potensi untuk mendegradasi senyawa organik hingga tingkat mineralisasi, sehingga tidak meninggalkan residu (sludge. Penelitian ini bertujuan membuat reaktor fotokatalitik rotating drum dan mengaplikasikan pada industri tekstil. Langkah percobaan meliputi pembuatan katalis TiO2 secara anodizing serta karakterisasi dengan XRD dan SEM, pembuatan reaktor fotokatalitik  rotating drum dan uji coba degradasi air limbah industri tekstil. Proses anodizing dilakukan dengan bias potensial sebesar 40 volt selama 2 jam menggunakan elektrolit etilen glikol yang mengandung amonium fluorida dan air. Uji karakterisasi secara XRD dan SEM menunjukkan bahwa struktur kristal TiO2 adalah anatase dengan ukuran kristalit 8–19 nm. Bentuk kristal nanotube, dengan diameter 30–110 nm. Hasil uji coba menunjukkan bahwa  degradasi secara fotokatalitik dengan penambahan H2O2 0,15% terhadap air limbah bisa menurunkan COD 72,12% dalam waktu 2 jam. 

  18. Penentuan Konversi CO Yang Menjadi Metanol Pada Metanol Reaktor Di PT. Kaltim Metanol Industri

    OpenAIRE

    Marduansyah, Muhammad

    2015-01-01

    Telah dilakukan penelitian tentang penentuan konversi CO yang menjadi metanol pada reaktor metanol, di PT. Kaltim Metanol Industri dimana dalam penelitian ini digunakan data laju alir dan komposisi gas yang didapat dari control room. Dari perhitungan yang dilakukan maka didapat hasil konversi CO pada tanggal 25 februari 2013 yaitu 74,93%. Selain itu juga didapat hasil data perhitungan yang sebelumnya telah dilakukan yaitu 61,21% pada 12 november 2012; 68,53% pada 13 april 2012; 66,89% pada 14...

  19. Penentuan Konversi CO Yang Menjadi Metanol Pada Metanol Reaktor Di PT. Kaltim Metanol Industri

    OpenAIRE

    Marduansyah, Muhammad

    2015-01-01

    Telah dilakukan penelitian tentang penentuan konversi CO yang menjadi metanol pada reaktor metanol, di PT. Kaltim Metanol Industri dimana dalam penelitian ini digunakan data laju alir dan komposisi gas yang didapat dari control room. Dari perhitungan yang dilakukan maka didapat hasil konversi CO pada tanggal 25 februari 2013 yaitu 74,93%. Selain itu juga didapat hasil data perhitungan yang sebelumnya telah dilakukan yaitu 61,21% pada 12 november 2012; 68,53% pada 13 april 2012; 66,89% pada 14...

  20. ANALISIS LAJU DOSIS NEUTRON REAKTOR PLTN PWR 1000 MWe MENGGUNAKAN PROGRAM MCNP

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    Amir Hamzah

    2015-03-01

    Full Text Available Dalam rangka menyongsong PLTN pertama di Indonesia, dilakukan kajian dan analisis berbagai aspek teknologi reaktor tersebut. Tujuan dari penelitian ini adalah menentukan laju dosis neutron di luar perisai biologik reaktor PLTN PWR 1000 MWe yang merupakan bagian dari kegiatan besar di atas. Data hasil analisis laju dosis radiasi pada posisi tertentu sangat dibutuhkan untuk menunjukkan tingkat paparan radiasi di posisi tersebut. Analisis laju dosis neutron ditentukan berdasarkan hasil analisis fluks dan spektrum neutron. Analisis fluks dan spektrum neutron di teras reaktor daya PWR 1000 Mwe dilakukan menggunakan program MCNP. Model perhitungan yang dilakukan meliputi 9 zona material yaitu, teras, air, selimut, air, tong, air, bejana tekan, beton dan lapisan udara luar. Penentuan distribusi fluks dan spektrum neutron dilakukan ke arah radial hingga di luar perisai beton dengan akurasi antara 10% hingga 30% dalam tiap kelompok energi yang jumlahnya 1 dan 50 kelompok. Hasil analisis laju dosis neutron di permukaan perisai biologik reaktor PLTN PWR 1000 MWe pada kondisi reaktor beroperasi daya penuh sudah di bawah nilai batas keselamatan. Maka dapat disimpulkan bahwa dari segi paparan radiasi neutron, penggunaan perisai radiasi beton setebal dua meter sudah memenuhi persyaratan keselamatan. Kata kunci: PLTN PWR, fluks neutron, perisai, laju dosis neutron, MCNP.   In order to meet the first nuclear power plant in Indonesia, it has been conducted a study and analysis of various aspects of reactor technology. The purpose of this study was to determine the neutron dose rates at the outside of biological shield of NPP PWR 1000 MWe reactor that is a part of the activities described above. The analysis data of radiation dose rate at a specific position is needed to show the level of radiation exposure in those positions. Analysis neutron dose rate is determined based on the results of the analysis of neutron flux. Analysis of flux and neutron spectrum in

  1. STUDI KARAKTERISTIK PEMBENTUKAN UAP DALAM PEMBANGKIT UAP HELIKAL PADA REAKTOR MODULAR DAYA KECIL

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    Susyadi Susyadi

    2015-06-01

    Full Text Available Reaktor modular daya kecil (SMR sangat cocok untuk  dibangun Indonesia, terutama pada lokasi-lokasi dengan kapasitas jaringan listrik yang rendah sehingga investigasi lebih jauh tentang reaktor ini sangat diperlukan. Umumnya SMR memiliki bentuk pembangkit uap yang kompak dan terintegrasi di dalam bejana tekan. Disain tersebut menyebabkan perbedaan pendekatan dalam memproduksi uap dibandingkan reaktor nuklir konvensional yang menggunakan pembangkit uap tabung-u terbalik. Oleh karena itu tujuan dari penelitian ini adalah untuk mengetahui karakteristik uap dan pola pembentukkannya di dalam pembangkit uap tipe helikal yang banyak digunakan oleh SMR. Metoda yang dipakai adalah dengan melakukan pemodelan dan perhitungan numerik menggunakan program RELAP5. Dalam pemodelan, aliran air umpan  bertekanan dan temperatur rendah dimasukkan ke dalam tabung helikal sementara aliran fluida bertekanan dan temperatur tinggi, yang mewakili pendingin sistem primer reaktor, berada di sisi luar tabung. Hasil perhitungan menunjukkan bahwa uap yang dihasilkan oleh pembangkit uap helikal bersifat lewat jenuh yakni sekitar 25 K di atas titik jenuhnya. Hal ini memberikan keunggulan komparatif dari segi disain dan operasional pada SMR dibanding reaktor konvensional karena uap lewat jenuh yang dihasilkan dapat mengurangi kerugian turbin dan sekaligus meningkatkan efisiensi termodinamika. Kata kunci: pembangkit uap helikal, SMR, PWR, uap lewat jenuh, RELAP5   Small modular reactor (SMR is very suitable to be deployed in Indonesia especially for locations having low electrical grid capacity, so  further investigation on the characteritic of this reactor is needed. In general SMR has a compact and integrated-to-vessel steam generator design. This design implies different approach in producing steam as compared to conventional nuclear power plant  having inverted u-tube steam generator. For that reason, this research is intended to investigate the steam characteristic and

  2. PERHITUNGAN SUHU ELEMEN BAKAR REAKTOR TRIGA 2000 DALAM TABUNG SIPPING TEST MENGGUNAKAN CFD

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    K.A. Sudjatmi

    2015-03-01

    Full Text Available Telah dihitung suhu elemen bakar pada perangkat sipping test reaktor TRIGA 2000 Bandung. Perhitungan perlu dilakukan untuk memastikan bahwa suhu elemen bakar masih dibawah atau pada batas suhu elemen bakar yang diizinkan pada saat reaktor beroperasi, sehingga dapat dipastikan bahwa pada pelaksanaan pengujian dengan menggunakan perangkat ini, suhu masih dalam batas keselamatan. Perhitungan dilakukan dengan membuat model tabung sipping test berisi elemen bakar yang dikelilingi oleh 9 buah elemen bakar, sesuai dengan posisi tabung sipping test di teras reaktor, dengan menggunakan GAMBIT. Dimensi model disesuaikan dengan dimensi tabung dan elemen bakar dalam teras reaktor TRIGA 2000 Bandung. Pengoperasian sipping test untuk tiap elemen bakar dilakukan selama 30 menit pada daya 300 kW. Perhitungan dilakukan dengan menggunakan perangkat lunak Computational Fluid Dynamics (CFD dan sebagai inputan disesuaikan dengan parameter reaktor TRIGA 2000. Simulasi dilakukan pada pengoperasian dari 30, 60, 90, 120 150, 180 sampai 210 menit. Hasil perhitungan menunjukan bahwa suhu pusat bahan bakar dalam tabung sipping test sebesar 236,06 oC, sedangkan suhu dinding elemen bakar adalah sebesar 87,58 oC. Suhu maksimum pusat bahan bakar reaktor TRIGA 2000 pada operasi normal adalah 650 oC, dan tidak diizinkan terjadinya pendidihan di dalam teras reaktor. Jadi dapat disimpulkan bahwa pengoperasian perangkat sipping test masih sangat aman karena suhu bahan bakar berada dibawah batasan suhu bahan bakar yang diizinkan pada kondisi operasi normal demikian juga suhu dinding elemen bakar masih dibawah suhu didih air. Kata kunci: sipping test, TRIGA, elemen bakar, CFD   It has been calculated the fuel element temperature in the sipping test of Bandung TRIGA 2000 reactor. The calculation needs to be done to ascertain that the fuel element temperatures are below or at the limit of the allowable temperature fuel elements during reactor operation, ensuring that the

  3. ANALISIS KONDISI TERAS REAKTOR DAYA MAJU AP1000 PADA KECELAKAAN SMALL BREAK LOCA

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    Andi Sofrany Ekariansyah

    2015-06-01

    Full Text Available ABSTRAK ANALISIS KONDISI TERAS REAKTOR DAYA MAJU AP1000 PADA KECELAKAAN SMALL BREAK LOCA. Kecelakaan yang diakibatkan oleh kehilangan pendingin (loss of coolant accident / LOCA dari sistem reaktor merupakan kejadian dasar desain yang tetap diantisipasi dalam desain reaktor daya yang mengadopsi teknologi Generasi II hingga IV. LOCA ukuran kecil (small break LOCA memiliki dampak yang lebih signifikan terhadap keselamatan dibandingkan LOCA ukuran besar (large break LOCA seperti terlihat pada kejadian Three-Mile Island (TMI. Fokus makalah adalah pada analisis small break LOCA pada reaktor daya maju Generasi III+ yaitu AP1000 dengan mensimulasikan tiga kejadian pemicu yaitu membukanya katup Automatic Depressurization System (ADS secara tak disengaja, putusnya salah satu pipa Direct Vessel Injection (DVI secara double-ended, dan putusnya pipa lengan dingin dengan diameter bocoran 10 inci. Metode yang digunakan adalah simulasi kejadian pada model AP1000 yang dikembangkan secara mandiri menggunakan program perhitungan RELAP5/SCDAP/Mod3.4. Dampak yang ingin dilihat adalah kondisi teras selama terjadinya small break LOCA yang terdiri dari pembentukan mixture level dan transien temperatur kelongsong bahan bakar. Hasil simulasi menunjukkan bahwa mixture level untuk semua kejadian small break LOCA berada di atas tinggi teras aktif yang menunjukkan tidak terjadinya core uncovery. Adanya mixture level berpengaruh pada transien temperatur kelongsong yang menurun dan menunjukkan pendinginan bahan bakar yang efektif. Hasil di atas juga identik dengan hasil perhitungan program lain yaitu NOTRUMP. Keefektifan pendinginan teras juga disebabkan oleh berfungsinya injeksi pendingin melalui fitur keselamatan pasif yang menjadi ciri reaktor daya AP1000. Secara keseluruhan, hasil analisis menunjukkan model AP1000 yang telah dikembangkan dengan RELAP5 dapat digunakan untuk keperluan analisis kecelakaan dasar desain pada reaktor daya maju AP1000. Kata kunci: analisis

  4. ANALISIS SEBARAN RADIONUKLIDA PADA KONDISI NORMAL UNTUK REAKTOR AEC 1000 MW

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    Sri Kuntjoro

    2015-03-01

    Full Text Available Telah dilakukan analisis sebaran radionuklida pada reaktor daya Atomic Energy Agency (AEC 3568 MWTh, setara dengan 1000 Mwe untuk kondisi operasi normal. Analisis dilakukan untuk dua reaktor yang terpisah sejauh 500 m dan sudut 90o satu dengan yang lain. Langkah awal dalam melakukan analisis adalah menentukan suku sumber reaktor menggunakan program komputer ORIGEN2 dan EMERALD NORMAL. ORIGEN2 digunakan untuk menentukan inventori radionuklida yang terdapat di reaktor. Selanjutnya dengan dengan menggunakan program EMERALD NORMAL dihitung suku sumber yang sampai ke cerobong reaktor. Untuk menganalisis dosis yang diterima penduduk dilakukan dengan menggunakan program PC-CREAM. Perhitungan dilakukan untuk satu dan dua PLTN di calon tapak PLTN. Hasil yang diperoleh adalah sebaran radionuklida terbesar untuk satu PLTN pada jarak 1 km dan kearah zona 9 (191,25o dan untuk dua PLTN pada jarak 1 km dan kearah zona 10 (213,75o. Radionuklida yang sampai ke penduduk melalui dua alur yaitu alur makanan dan hirupan. Untuk alur makanan berasal dari radionuklida I-131, dan terbesar melalui alur produk susu sebesar 53,40 % untuk satu maupun dua PLTN . Untuk alur hirupan ranionuklida pemberi kontribusi paparan terbesar berasal dari Kr-85m sebesar 53,80 %. Dosis total terbesar yang diterima penduduk terdapat pada jarak 1 Km untuk bayi yaitu sebesar 4,10 μSi dan 11,26 μSi untuk satu dan dua PLTN. Hasil ini sangat kecil dibandingkan dengan batas dosis yang diijinkan oleh badan pengawas (BAPETEN untuk penduduk yaitu sebesar 1 mSi. Kata Kunci : Reaktor daya, komputer code, radionuklida, alur makanan, hirupan   Analysis for radionuclide dispersion for the Atomic Energy Agency (AEC 3568 MWth Power Reactor, equal to the 1000 MWe at normal condition has been done. Analysis was done for two piles that is separated by 500 m distance and angle of 90o one to other. Initial pace in doing the analysis is to determine reactors source term using ORIGEN2 and EMERALD NORMAL

  5. ANALISIS DAN PENGUKURAN PARAMETER REAKTOR KARTINI UNTUK PENERAPAN METODE K0-NAA

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    Sri Murniasih

    2015-03-01

    Full Text Available Metode k0-NAA merupakan metode analisis yang banyak digunakan dengan berbagai keunggulan. Dalam penerapan metode k0-NAA diperlukan nilai parameter reaktor (f dan α, maka tujuan penelitian ini adalah akan dilakukan pengukuran nilai parameter f dan α di fasilitas Lazy Susan reaktor Kartini. Metode yang digunakan meliputi metode Cd-ratio dan triple bare. Telah diukur nilai parameter tersebut pada tiga lubang iradiasi di fasilitas Lazy Susan. Diperoleh perbedaan hasil pengukuran nilai parameter yang signifikan pada setiap lubang iradiasi, nilai ƒ berkisar 13,713 - 22,128 dan α berkisar -0,060 – 0,068. Hasil pengukuran f dan α dengan metode Cd-ratio, memberikan nilai yang lebih stabil dibandingkan metode triple bare. Nilai f dan α yang diperoleh dapat dijadikan basis data pada penerapan metode k0-NAA untuk analisis sampel di laboratorium AAN – PSTA. Kata kunci: parameter reaktor, reaktor Kartini, k0-NAA, fluks neutron   The k0-NAA method is an analysis method that widely used by many of the advantages. In the application of k0-NAA method needed valuea of reactor parameters (f and α, then the purpose of the research would be conducted meaasurement parameter values f and α in the Lazy Susan Kartini reactor facilities. The methods used include Cd-ratio and triple bare methods. The parameter value has been measured in three channels in the irradiation facilities Lazy Susan. Differences of measurement results obtained parameter values are significant in each channel irradiation, the value of ƒ ranged from 13.713 to 22.128 and the value of α ranged from -0.060 – 0.068. The results of measurements for the f and α with the Cd-ratio method, providing more stable value than the triple bare method. The value of f and α obtained can be used a database for the application of k0-NAA method for sample analysis in the laboratory NAA – CAST. Keywords: reactor parameter, Kartini reactor, k0-NAA, neutron flux

  6. VERIFIKASI KECELAKAAN HILANGNYA ALIRAN AIR UMPAN PADA REAKTOR DAYA PWR MAJU

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    Andi Sofrany Ekariansyah

    2015-03-01

    Full Text Available AP1000 adalah reaktor daya PWR maju dengan daya listrik 1154 MW yang didesain berdasarkan kinerja teruji dari desain PWR lain oleh Westinghouse. Untuk mempersiapkan peran Pusat Teknologi Reaktor dan Keselamatan Nuklir sebagai suatu Technical Support Organization (TSO dalam hal verifikasi keselamatan, telah dilakukan kegiatan verifikasi keselamatan untuk AP1000 yang dimulai dengan verifikasi kecelakaan kegagalan pendingin sekunder. Kegiatan dimulai dengan pemodelan fitur keselamatan teknis yaitu sistem pendinginan teras pasif yang terdiri dari sistem Passive Residual Heat Removal (PRHR, tangki core makeup tank (CMT, dan tangki In-containment Refueling Water Storage Tank (IRWST. Kecelakaan kegagalan pendingin sekunder yang dipilih adalah hilangnya aliran air umpan ke salah satu pembangkit uap yang disimulasikan menggunakan program perhitungan RELAP5/SCDAP/Mod3.4. Tujuan analisis adalah untuk memperoleh sekuensi perubahan parameter termohidraulika reaktor akibat kecelakaan dimana hasil analisis yang diperoleh divalidasi dan dibandingkan dengan hasil analisis menggunakan program perhitungan LOFTRAN di dalam dokumen desain keselamatan AP1000. Hasil verifikasi menunjukkan bahwa kejadian hilangnya suplai air umpan tidak berdampak pada kerusakan teras, sistem pendingin reaktor, maupun sistem sekunder. Penukar kalor PRHR telah terverifikasi kemampuannya dalam membuang kalor peluruhan teras setelah trip reaktor. Hasil validasi dengan dokumen pembanding menunjukkan kesesuaian pada sebagian besar parameter termohidraulika. Secara umum, model PWR maju yang dilengkapi dengan sistem pendinginan teras ciri pasif yang telah dikembangkan tetap selamat ketika terjadi kecelakaan kehilangan aliran pendingin sekunder. Kata kunci: Verifikasi, hilangnya aliran air umpan, AP1000   AP1000 is a PWR power reactor with 1154 MW of electrical power that is designed based on the proven performance of the other Westinghouse PWR designs. To prepare the role of Center for

  7. ANALISIS DESAIN PROSES SISTEM PENDINGIN PADA REAKTOR RISET INOVATIF 50 MW

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    Sukmanto Dibyo

    2015-03-01

    Full Text Available Reaktor Riset Inovatif (RRI merupakan jenis MTR (Material Testing Reactor yang dipersiapkan ke depan sebagai desain reaktor baru. Daya RRI telah ditetapkan dari perhitungan neutronik dan termohidrolika teras yaitu 50 MW termal. Reaktor bertekanan 8 kgf/cm2 dan laju aliran massa pendingin primer 900 kg/s. Tantangan yang penting dalam menindak lanjuti desain reaktor ini adalah analisis desain pada sistem pendingin. Makalah ini bertujuan untuk menganalisis desain proses sistem pendingin utama reaktor RRI daya 50 MW (RRI-50 dengan menggunakan program Chemcad 6.1.4. Dalam analisis ini dilakukan perhitungan neraca massa dan energi (mass/energy balances pada sistem pendingin primer dan sekunder sebagai pendingin utama. Masing-masing sistem pendingin tersebut terdiri dari 2 jalur beroperasi secara paralel dan 1 jalur redundansi. Disamping itu untuk desain termal unit komponen telah dianalisis dengan program RELAP5, frenchcreek dan Metoda Analitik. Hasil analisis yang diperoleh adalah desain diagram sistem pendingin yang mencakup data parameter entalpi, temperatur, tekanan dan laju aliran massa pendingin untuk masing-masing jalur. Adapun hasil desain unit komponen utama pada RRI-50 adalah tangki tunda dengan volume 51,5 m3, 2 unit pompa sentrifugal dan 1 unit pompa cadangan pada pendingin primer daya 141 kW/pompa dan pendingin sekunder daya 206 kW/pompa, 2 unit penukar panas tipe shell-tube dengan koefisien termal overall 1377 W/m2.oC dan 4 unit menara pendingin yang mampu melepaskan panas ke udara dengan desain temperatur approach 5,0 oC dan temperatur range 9,0 oC. Desain sistem pendingin reaktor RRI-50 ini telah menetapkan parameter operasi sistem pendingin yaitu temperatur, tekanan dan laju aliran massa pendingin dengan mempertimbangkan tuntutan aspek keselamatan teras reaktor sehingga desain temperatur maksimum pendingin masuk ke teras 44,5 oC. Kata kunci : RRI 50 MW, desain sistem pendingin, program Chemcad 6.1.4   Innovative Research Reactor RRI

  8. ANALISIS AKTIVITAS SUMBER RADIASI DAN INTENSITAS SINAR GAMMA DI TERAS REAKTOR PWR 1000 MWe

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    Ardani Ardani

    2015-04-01

    Full Text Available Salah satu PLTN kelas 1000 MWe adalah AP1000, reaktor dengan daya operasi penuh 3400 MWt. Sinar gamma dalam teras reaktor berasal dari tiga jenis sumber: 1 sinar gamma hasil reaksi penangkapan radiatif, 2 sinar gamma hasil reaksi pembelahan spontan dan 3 sinar gamma peluruhan radionuklida hasil pembelahan dan peluruhan radionuklida hasil aktivasi material dalam teras. Komposisi nuklida dalam teras merupakan parameter untuk menentukan laju reaksi penangkapan radiatif. Paket program ORIGEN-2 digunakan untuk menghitung aktivitas radionuklida dalam teras reaktor dan intensitas sinar gamma peluruhannya. Dengan asumsi reaktor dioperasikan pada daya penuh selama 540 hari tanpa gangguan, sebagian besar aktivitas radionuklida hasil pembelahan cenderung stabil, sedangkan aktivitas radionuklida hasil aktivasi material dan aktivitas aktinida cenderung meningkat seiring dengan waktu operasi. Aktivitas terbesar adalah aktivitas radionuklida hasil pembelahan yang totalnya mencapai 6,8×109 curie pada akhir operasi, diikuti aktivitas aktinida 1,06×109 curie, kemudian aktivitas radionuklida hasil aktivasi 5,98×106 curie. Energi sinar gamma terentang antara 0 - 11 MeV, dikelompokkan dalam 7 kelas energi. Sumber sinar gamma penangkapan radiatif memberikan kontribusi intensitas yang paling tinggi diikuti oleh intensitas sinar gamma hasil pembelahan spontan kemudian intensitas sinar gamma hasil peluruhan. Secara umum sinar gamma kelas energi rendah mempunyai intensitas yang lebih besar dibanding intensitas sinar gamma kelas energi tinggi. Kata kunci : PLTN AP1000, aktivitas radionuklida, curie, intensitas sinar gamma, foton   One of the 1000 MWe class nuclear power plant is the AP1000, full operating power reactors by 3400 MWt. Gamma rays in the reactor core derived from three types of sources :1 gamma ray results of radiative capture reactions,2 gamma rays result of spontaneous fission reaction and 3 gamma ray decay of radionuclides and the decay of the fission

  9. KINETIKA REAKSI OKSIDASI KATALITIK FERO SULFAT DARI LIMBAH BESI DALAM REAKTOR LULUHAN

    Directory of Open Access Journals (Sweden)

    Hary Sulistyo

    2012-02-01

    Full Text Available Limbah besi yang berupa serbuk direaksikan dengan asam sulfat membentuk larutan fero sulfat. Larutan fero sulfat dapat dioksidasi menjadi feri sulfat. Oksidasi dijalankan dalam reaktor drift pada tekanan dan suhu tetap. Percobaan dilakukan pada kisaran suhu 323K sampai 353K dan konsentrasi katalisator dari 1,7 sampai 6,7 g/L, waktu reaksi 150 menit pada tekanan atmosferis. Nilai konversi tertinggi fero sulfat menjadi feri sulfat yang diperoleh 39,5%. Nilai koefisien perpindahan massa gas ke cairan dan cairan ke permukaan padatan berturut-turut 37,18 cm/s dan 180 cm/s. Hubungan antara konstante kecepatan reaksi permukaan dengan suhu dapat dinyatakan dalam bentuk persamaan Arrhenius, k = 2,8092x107exp(-8794/RT. Hasil penelitian yang diperoleh sesuai dengan data di pustaka dan kinetika reaksi ditentukan oleh gabungan antara perpindahan massa gas ke cairan dan reaksi pada permukaan katalisator. 

  10. Disain Sistem Pemantauan Lingkungan Untuk Evaluasi Lepasan Radionuklida dari Subsistem pada Kecelakaan Reaktor Daya PWR

    Directory of Open Access Journals (Sweden)

    Sri Kuntjoro

    2013-03-01

    Full Text Available PLTN. (Pembangkit Listrik Tenaga Nuklir sebagai sumber energi baru dipilih sebagai alternatif, karena memiliki berbagai kelebihan yaitu ramah lingkungan, pasokan bahan bakar yang tidak bergantung musim, serta harganya yang dapat bersaing dengan pembangkit listrik yang lain. Namun demikian, adanya keraguan sebagian masyarakat tentang keselamatan radiasi PLTN, maka pemerintah harus bisa meyakinkan tentang operasi PLTN yang aman dan selamat. Penelitian tentang disain sistem pemantauan lingkungan untuk evaluasi lepasan radionuklida dari subsistem reaktor dan lingkungan akibat terjadinya kecelakaan pada reaktor daya telah dilakukan. Penelitian dilakukan dengan melakukan perhitungan sebaran radionuklida ke subsistem dan lingkungan serta membuat sistim monitoring radiasi di lingkungan. Sistem monitoring lingkungan terdiri dari system pencacah radiasi, sistem peringatan dini, sistem pengukuran meteorologi, sistem GPS dan system GIS. Sistem pencacah radiasi digunakan untuk mencatat data radiasi, sistem pengukuran meteorologi digunakan untuk mencatat data arah dan kecepatan angin, sedangkan sistem GPS digunakan untuk menentukan data posisi pengukuran. Data tersebut kemudian dikirimkan ke system akuisisi data untuk ditransmisikan ke pusat kendali. Pengumpulan dan pengiriman data dilakukan melalui SMS menggunakan perangkat modem yang ditempatkan di ruang kendali. Ruang kendali menerima data dari berbagai tempat pengukuran. Dalam hal ini ruang kendali memiliki fungsi sebagai SMS gateway. Sistem ini dapat memvisualisasi untuk lokasi pengukuran yang berbeda. Selanjutnya, data posisi dan data radiasi diintegrasikan dengan peta digital. Integrasi sistem tersebut kemudian divisualisasikan dalam personal komputer. Untuk posisi pengukuran terlihat langsung di peta dan untuk data radiasi ditampilkan di monitor dengan tanda lingkaran merah atau hijau yang digunakan sebagai pemonitor batas aman radiasi. Bila tanda lingkaran berwarna merah maka akan menyalakan alarm di

  11. Isotopic composition of precipitation at the station Ljubljana (Reaktor, Slovenia – period 2007–2010

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    Polona Vreča

    2014-12-01

    Full Text Available The stable isotopic composition of hydrogen and oxygen (δ2H and δ18O and the tritium activity (A were monitored in monthly collected precipitation at Ljubljana (Reaktor during the period 2007–2010. Monthly and yearly isotope variations are discussed and compared with those observed over the period 1981–2006 and with the basic meteorological parameters for Ljubljana (Bežigrad and Ljubljana (Hrastje stations for the period 2007−2010. The mean values for δ2H and δ18O, weighted by precipitation amount at Ljubljana (Reaktor, are –59.4 ‰ and –8.71 ‰. The reduced major axis local meteoric water line (LMWLRMA is δ2H = (8.19 ± 0.22×δ18O + (11.52 ± 1.97, while the precipitation weighted least square regression results in LMWLPWLSR-Re δ2H = (7.94 ± 0.21×δ18O + (9.76 ± 1.93. The lack of significant difference in the LMWL slopes indicates a relatively homogeneous distribution of monthly precipitation as well as the small number of low-amount monthly precipitation events with low deuterium excess. The deuterium excess weighted mean value is 10.3 ‰ which indicates the prevailing influence of the Atlantic air masses. The temperature coefficient of δ18O is 0.30 ‰/°C. Tritium activity in monthly precipitation shows typical seasonal variations, with a weighted mean tritium activity in this period of 8.5 TU. No decrease of mean annual activity is observed.

  12. PENGARUH GEMPA PATAHAN LEMBANG TERHADAP FLEKSIBILITAS PIPA DAN KEGAGALAN NOZEL PERALATAN SISTEM PENDINGIN PRIMER REAKTOR TRIGA 2000 BANDUNG

    Directory of Open Access Journals (Sweden)

    H.P. Raharjo

    2012-02-01

    Full Text Available Gempa bumi di suatu instalasi nuklir dapat menyebabkan terjadinya kerusakan sistem peralatan karena adanya perubahan fleksibilitas pipa akibat beban berlebih pada sistem perpipaannya. Beban dari sistem perpipaan dapat membebani nozel peralatan seperti pompa, penukar panas, dll. Apabila beban tersebut terlalu besar dan melebihi beban yang diizinkan akan mengakibatkan kegagalan nozel peralatan. Penelitian ini menganalisis besarnya beban-beban yang terjadi di semua nozel  sistem pendingin primer Reaktor TRIGA 2000 Bandung. Analisis dilakukan dengan bantuan perangkat lunak Caesar II yang berbasis metode elemen hingga (finite element method. Acuan analisis yang digunakan adalah code ASME B31.1 yang mengatur tentang perancangan sistem perpipaan untuk sistem pembangkit daya (Power Piping. Hasil analisis menunjukkan bahwa gaya yang terjadi pada nozel masukan pompa arah aksial (FZ melebihi batas yang diijinkan. Oleh karena itu perlu dilakukan modifikasi terhadap jalur perpipaan sistem pendingin tersebut agar nozel tidak menerima gaya yang berlebih. Penyangga pipa titik(node 22 di jalur PriOut dilepas dan/atau dipindahkan pada nozel masukkan pompa. Perpipaan sistem pendingin primer reaktor TRIGA 2000 Bandung akan aman beroperasi jika terjadi gempa.yang berasal dari patahan Lembang Kata kunci : gempa bumi, patahan, perpipaan, reaktor, sistem pendingin

  13. PEMBUATAN SERBUK U-6Zr DENGAN PENGKAYAAN URANIUM 19,75 % UNTUK BAHAN BAKAR REAKTOR RISET

    Directory of Open Access Journals (Sweden)

    Masrukan Masrukan

    2016-03-01

    Full Text Available ABSTRAK PEMBUATAN SERBUK PADUAN U-6Zr DENGAN PENGKAYAAN URANIUM 19,75 % UNTUK BAHAN BAKAR REAKTOR RISET. Telah dilakukan pembuatan serbuk paduan U-6Zr dengan pengkayaan 19,75 % untuk bahan bakar reaktor riset. Pembuatan bahan bakar U-6Zr ini dalam rangka mencari bahan bakar baru yang mempunyai densitas tinggi untuk mengganti bahan bakar yang sudah ada U3Si2-Al. Tujuan dari percobaan ini untuk mengetahui sifat-sifat serbuk paduan U- 6Zr yang diperoleh dari proses hydriding-dehydriding sebagai kandidat bahan bakar reaktor riset. Serbuk yang diperoleh dari proses hydriding-dehydriding dikenai pengujian, diantaranya pungujian komposisi kimia, densitas, kandungan hidrogen, fasa dan sifat termal. Hasil pengujian komposisi kimia menunjukkan beberapa unsur seperti Al, Ca, Cu, dan Ni melebihi batas yang diijinkan dimana masing-masing unsur terdapat sebesar 202,21 ppm; 214,05 ppm; 61,25 ppm dan 134,53 ppm. Pada pengujian diperolah densitas serbuk U-6Zr sebesar 13,58 g/cm3 dan pada pengujian kandungan hidrogen sisa diperoleh kandungan hidrogen sebesar 0,16 %. Untuk pengujian fasa, diperoleh fasa αU dan δU, sedangkan pada pengujian sifat termal yakni transformasi temperatur terdapat dua puncak yakni puncak pertama terjadi pada temperatur 274 hingga 311 oC dan puncak kedua terjadi pada temperatur 493 hingga 527oC. Puncak pertama terjadi reaksi endotermik dengan menyerap panas sebesar ∆H = 6,23 cal/g tetapi tidak terbentuk fasa baru, sedangkan puncak kedua terjadi reaksi eksotermik dengan mengeluarkan panas sebesar ∆H = -9.34 cal/g dan terbentuk fasa αZr. Sementara itu, dari pengujian kapasitas panas pada temperatur 34 hingga 75 oC, terjadinya penurunan nilai kapasitas panas yang disertai dengan penyerapan panas. Pada temperatur yang lebih tinggi hingga temperatur 437oC nilai kapasitas panas menjadi lebih kecil disertai pengeluaran panas. Reaksi termokimia antara Zr dengan hidrogen sisa menunjukkan terbentuknya fasa αZr yang diindikasikan oleh reaksi

  14. Photoluminescence lifetime measurements in InP wafers

    Science.gov (United States)

    Landis, Geoffrey A.; Jenkins, Phillip; Weinberg, Irving

    1991-01-01

    A simple apparatus to measure the minority carrier lifetime in InP has been developed. The technique stimulates the sample with a short pulse of light from a diode laser and measures the photoluminescence decay to extract the minority carrier lifetime. The photoluminescence lifetime in InP as a function of doping on both n- and p-type material is examined. The results also show a marked difference in the lifetime of n-type InP and p-type InP of similar doping levels. N-type InP shows a lifetime considerably longer than the expected radiative limited lifetime.

  15. ANALISIS DISTRIBUSI KECEPATAN PENDINGIN DALAM ELEMEN BAKAR TIPE PELAT MENGGUNAKAN METODE CFD UNTUK REAKTOR RISET RSG-GAS

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    Muhammad Subekti

    2015-03-01

    Full Text Available Eksperimen pengukuran distribusi kecepatan pendingin dalam subkanal elemen bakar reaktor riset RSG-GAS sulit dilakukan karena lebar celah yang sangat kecil dan terletak di dalam elemen bakar. Oleh karena itu diperlukan perhitungan untuk memprediksi distribusi kecepatan pendingin dalam subkanal untuk mengkonfirmasi bahwa keberadaan handle tidak merusak distribusi kecepatan pendingin masuk ke dalam setiap subkanal. Perhitungan ini memerlukan metode CFD yang memperhatikan interior 3 dimensi. Perhitungan distribusi kecepatan pendingin dalam subkanal juga belum pernah dilakukan. Tujuan penelitian ini adalah melakukan investigasi distribusi kecepatan pendingin elemen bakar tipe pelat menggunakan metode CFD 3 dimensi untuk reaktor riset RSG-GAS. Penelitian ini juga sangat diperlukan sebagai bagian dari pengembangan desain termohidrolika elemen bakar untuk reaktor riset inovatif. Pemodelan menggunakan ½ model dalam perangkat lunak Gambit dan perhitungan menggunakan persamaan Turbulen dalam perangkat lunak FLUENT 6.3. Hasil perhitungan kecepatan pendingin tiga dimensi dalam subkanal menggunakan metode CFD lebih rendah sekitar 4,06% dari pada hasil perhitungan satu dimensi karena perhitungan satu dimensi mengabaikan keberadaan handle. Kata kunci: Aliran pendingin, elemen bakar, reaktor riset, kondisi tunak, CFD   The measurement experiment for coolant-velocity distribution in the subchannel of fuel element of RSG-GAS research reactor is difficult to be carried out due to too narrow channel and subchannel placed inside the fuel element. Hence, the calculation is required to predict the coolant-velocity distribution inside subchannel to confirm that the handle presence does not ruin the velocity distribution into every subchannel. This calculation utilizes CFD method, which respect to 3-dimension interior. Moreover, the calculation of coolant-velocity distribution inside subchannel was not ever carried out. The research object is to investigate the

  16. OPTIMASI GEOMETRI TERAS REAKTOR DAN KOMPOSISI BAHAN BAKAR BERBENTUK BOLA PADA DESAIN HIGH TEMPERATURE FAST REACTOR (HTFR

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    Agustina Mega

    2015-04-01

    Full Text Available Telah dilakukan desain High Temperature Fast Reactor (HTFR tipe pebble dengan bahan bakar uranium plutonium nitrida berpendingin Pb-Bi. Parameter yang dianalisis adalah kritikalitas teras, koefisien reaktivitas temperatur bahan bakar, koefisien reaktivitas void pendingin dan kemampuan breeding reaktor. Perhitungan dilakukan dengan paket program SRAC2K3. Dari penelitian ini diharapkan diperoleh desain teras berumur lama dan memiliki fitur keselamatan melekat. Dari penelitian ini diperoleh desain reaktor dengan diameter 520 cm dan tinggi 480 cm. Bahan bakar berbentuk pebble dengan 63 % UN-37 % PuN pada zona core dan 95,5 % UN-4,5 % PuN pada zona blanket. Reaktor tidak kritis setelah kurang lebih 800 hari dan keff pada BoL 1,078223 dan keff setelah 800 hari adalah 0,986379. Dari penelitian ini diperoleh koefisien reaktivitas temperatur bahan bakar sebesar -2,190014E-05 pada saat BoL dan -1,390773E-05 setelah 800 hari serta koefisien reaktivitas void pendingin sebesar -2,160402E-04/% void pada saat BoL dan setelah 800 hari sebesar -2,942364E-03/% void. Reaktor merupakan jenis fast breeder ditandai dengan naiknya densitas plutonium 239. Kata kunci : desain, teras, HTFR, keselamatan, umur, koefisien reaktivitas.   Design of pebble bed type High Temperature Fast Reactor (HTFR with uranium plutonium nitride fuel and Pb-Bi cooled has been done. The parameters being analyzed were core criticality, fuel temperature coefficient, void coefficient and reactor breeding ability. Calculation was done by using SRAC2K3 computer code. This research is expected to obtaine the design with long life core and inherent safety features. This research obtained core design with a diameter of 520 cm and 480 cm core high. Shaped pebble fuel bed with the 63 % UN-37 % PUN on core zone and 95.5 % UN-4.5 % Pu on blanket zone and keff value is 1.078223 with approximately 800 day of core life. The fuel temperature coefficient is -2.190014E-05 at BOL and is 1.390773E-05 at EOL and

  17. STUDI DESAIN DOWN SCALE TERAS REAKTOR DAN BAHAN BAKAR PLTN JENIS PEBBLE BED MODULAR REACTOR – HTR 100 MWe

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    Slamet Parmanto

    2015-04-01

    Full Text Available Telah dilakukan penelitian terhadap teras reaktor Pebble Bed Modular Reactor (PBMR dengan daya 100 Mwe berbahan bakar UO2. Reaktor ini menggunakan moderator grafit dan helium sebagai pendingin. Studi down scale dilakukan tanpa mengubah geometri teras maupun geometri bahan bakar. Parameter yang dianalisis adalah kritikalitas teras, reaktivitas lebih, koefisien reaktivitas temperatur bahan bakar, moderator dan pendingin serta nilai ekonomis bahan bakar. Dari penelitian ini diharapkan diperoleh desain bahan bakar yang bernilai ekonomis dan memiliki fitur keselamatan melekat. Penelitian dilakukan dengan menggunakan program SRAC 2003. Hasil yang diperoleh adalah desain bahan bakar UO2 berbentuk pebble dengan pengkayaan 10% U235 dan 90 ppm racun dapat bakar Gd2O3. Nilai faktor multipilkasi effektif keff pada beginning of life (BOL adalah 1,01115 dan menjadi 1,00588 setelah 2658 hari operasi reaktor (EOL. Koefisien reaktivitas temperatur total diperoleh sebesar - 3,25900E-05 ∆k/k/K saat BOL dan -1,10615E-04 ∆k/k/K saat end of life (EOL. Reaktor ini memenuhi karakteristik keselamatan melekat ditandai dengan nilai koefisien reaktivitas temperatur yang negatif. Kata kunci: PBMR, desain bahan bakar, faktor multipilkasi effektif, reaktivitas lebih, koefisien reaktivitas temperatur.   Research of Pebble Bed Modular Reactor (PBMR 100 MWe which used UO2 fuel has been done. This reactor uses graphite as moderator and helium as coolant. Down scale studies performed without changing the core and fuel geometry. The parameter being analyzed were core criticality, excess reactivity, fuel, moderator, coolant temperature reactivity coefficient, and fuel economy. This research is expected to obtain the design that has fuel economy and inherent safety features. In this research, we have employed SRAC 2003 code. The calculation show that the UO2 pebble fuel design with 10% enrichment of U235 and 90 ppm burnable poison of Gd2O3 results in the effective multiplication

  18. ANALISIS MODEL TERAS 3-DIMENSI UNTUK EVALUASI PARAMETER KRITIKALITAS REAKTOR PWR MAJU KELAS 1000 MW

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    Tagor Malem Sembiring

    2015-04-01

    Full Text Available Setelah kejadian Fukushima, penggunaan sistem keselamatan pasif menjadi persyaratan yang penting untuk PLTN. PLTN jenis PWR maju kelas 1000 yang didesain oleh Westinghouse, AP1000, memiliki fitur keselamatan pasif disamping sederhana dan modular. Sebelum memilih suatu PLTN, maka perlu dilakukan suatu evaluasi terhadap parameter desainnya. Salah satu parameter yang penting dalam keselamatan adalah kritikalitas teras. Permasalahan pokok dalam mengevaluasi parameter kritikalitas teras AP1000 tidak adanya data komposisi material SS304 dan H2O di daerah reflektor dan diameter penyerap SS304. Dengan demikian tujuan penelitian ini adalah mendapatkan model teras 3-dimensi AP1000 dan siap diaplikasikan dalam evaluasi parameter kritikalitas teras. Hasil perhitungan menunjukkan bahwa komposisi terbaik SS304 dan H2O di reflektor teras bagian atas dan bawah masing-masing 50 vol%, sedangkan diameter penyerap SS304 adalah 0,960 cm. Evaluasi konsentrasi boron kritis menunjukkan perbedaan yang signifikan dengan nilai desain. Meskipun penyebab utama dari perbedaan ini belum diketahui, akan tetapi dapat dibuktikan bahwa konsentrasi boron kritis sangat sensitif dengan densitas UO2. Untuk reaktivitas padam, reaktor AP1000 memiliki margin subkritikalitas teras yang besar untuk satu siklus operasi. Dengan demikian teras yang diusulkan dapat digunakan sebagai acuan untuk evaluasi parameter teras lainnya atau perangkat analitis lainnya dalam rangka mengevaluasi desain reaktor AP1000. Kata kunci: AP1000, kritikalitas, konsentrasi boron kritis, reaktivitas padam   After the Fukushima accident, the use of passive safety system becomes an important requirement for the nuclear power plant (NPP. The advanced PWR NPP with 1000 MW (electric class, designed by Westinghouse, AP1000, a reactor with the passive safety features as well as simple and modular. Before selecting a nuclear power plant, there should be an evaluation of the design parameter. One important parameter in

  19. VERIFIKASI PAKET PROGRAM MVP-II DAN SRAC2006 PADA KASUS TERAS REAKTOR VERA BENCHMARK.

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    Jati Susilo

    2015-03-01

    Full Text Available Dalam penelitian ini dilakukan verifikasi perhitungan benchmark VERA pada kasus Zero Power Physical Test (ZPPT teras reaktor Watts Bar 1. Reaktor tersebut merupakan jenis PWR kelas 1000 MWe yang didesain oleh Westinghouse, tersusun dari 193 perangkat bahan bakar 17×17 dengan 3 jenis pengkayaan UO2 yaitu 2,1wt%, 2,619wt% dan 3,1wt%. Perhitungan nilai k-eff dan distribusi faktor daya dilakukan pada siklus operasi pertama teras dengan kondisi beginning of cycle (BOC dan hot zero power (HZP. Posisi batang kendali dibedakan menjadi uncontrolled (semua batang kendali berada di luar teras, dan controlled (batang kendali Bank D didalam teras. Paket program komputer yang digunakan dalam perhitungan adalah MVP-II dan SRAC2006 modul CITATION dengan data pustaka tampang lintang ENDF/B-VII.0. Hasil perhitungan menunjukkan bahwa perbedaan nilai k-eff teras pada kondisi controlled dan uncontrolled antara referensi dengan MVP-II (-0,07% dan -0,014% dan SRAC2006 (0,92% dan 0,99% sangat kecil atau masih dibawah 1%. Perbedaan faktor daya maksimum teras pada kondisi controlled dan uncontrolled dengan referensi dengan MVP-II adalah 0,38% dan 1,53%, sedangkan dengan SRAC2006 adalah 1,13% dan -2,45%. Dapat dikatakan bahwa kedua paket program komputer menunjukkan hasil perhitungan yang sesuai dengan nilai referensi. Dalam hal penentuan kekritisan teras, maka hasil perhitungan MVP-II lebih konservatif dibandingkan dengan SRAC2006. Kata kunci : MVP-II, SRAC2006, PWR, VERA   In this research, verification calculation for VERA core physics benchmark on the Zero Power Physical Test (ZPPT of the nuclear reactor Watts Bar 1. The reactor is a 1000 MWe class of PWR designed by Westinghouse, arranged from 193 unit of 17×17 fuel assembly consisting 3 type enrichment of UO2 that are 2.1wt%, 2.619wt% and 3.1wt%. Core power factor distribution and k-eff calculation has been done for the first cycle operation of the core at beginning of cycle (BOC and hot zero power (HZP. In this

  20. Thermal diffusion in nanostructured porous InP

    Indian Academy of Sciences (India)

    R Srinivasan; K Ramachandran

    2008-11-01

    Nanostructured porous InP samples were prepared by electrochemical anodic dissolution of InP for various current densities and etching periods. The samples were characterized by SEM and photoluminescence (PL) where a blue shift was observed in PL. Thermal properties studied by photoacoustic (PA) spectroscopy revealed one order decrease in thermal conductivity of porous InP compared to the bulk. Further it is shown that the thermal conductivity of porous InP decreases with decrease in size of the particles.

  1. PERFORMA OKSIDASI METAN PADA REAKTOR KONTINYU DENGAN PENINGKATAN KETEBALAN LAPISAN BIOCOVER LANDFILL

    Directory of Open Access Journals (Sweden)

    Opy Kurniasari

    2013-11-01

    methane through the form of methanol metabolite. ABSTRAKPenanganan sampah kota di Indonesia pada umumnya dilakukan pada tempat pemrosesan akhir sampah (TPA, yang sebagian besar dilakukan dengan cara pengurugan (landfilling yang cenderung bersifat anaerob (tidak ada oksigen. Cara pengurugan ini biasanya dioperasikan lapis perlapis sehingga memungkinkan terjadinya proses anaerob. Pada kondisi ini dipastikan biogas, yaitu gas metana (CH4 dan CO2, akan muncul. Metana adalah gas rumah kaca dengan potensi pemanasan global lebih besar dari CO2, dan dapat mengabsorpsi radiasi infra merah 23 kali lebih efisien dari CO2 pada periode lebih dari 100 tahun. Salah satu cara yang dapat dilakukan untuk mengurangi gas metana dari landfill yang lepas ke alam adalah dengan mengoksidasinya dengan memanfaatkan material penutup landfill (biocover sebagai media mikroorganisma pengoksidasi metana. Aplikasi kompos sebagai material penutup landfill merupakan pendekatan dengan biaya rendah untuk mereduksi emisi gas dari landfill sehingga cocok untuk negara berkembang. Biocover yang digunakan pada penelitian ini adalah kompos landfill mining, yaitu kompos yang terdegradasi secara alami di landfill. Tujuan penelitian ini adalah mengevaluasi kemampuan biocover kompos landfill mining dalam mengoksidasi metana pada ketebalan lapisan tertentu dengan kondisi aliran kontinyu. Tiga buah reaktor kolom yang digunakan terbuat dari flexy glass berukuran tinggi 70 cm dan diameter 15 cm. Gas metana dialirkan dari bawah reaktor secara kontinyu dengan laju alir 5 ml/menit. Kolom diisi dengan biocover kompos landfill mining dengan ketebalan lapisan 5, 25, 35 dan 60 cm. Hasil percobaan menunjukkan bahwa semakin tebal lapisan biocover, semakin tinggi efisiensi oksidasi metana. Efisiensi oksidasi yang diperoleh pada setiap ketebalan lapisan 15, 25, 35 dan 60 cm adalah masing-masing 56,43%, 63,69%, 74,58% dan 80,03%, dengan laju oksidasi 0,287 mol m-2 d-1 dan fraksi oksidasi 97%. Hasil oksidasi yang diperoleh tersebut

  2. ANALISIS PENGARUH IRADIASI FLUENS NEUTRON CEPAT TERHADAP BERILIUM REFLEKTOR REAKTOR RSG-GAS

    Directory of Open Access Journals (Sweden)

    Sri Kuntjoro

    2015-04-01

    Full Text Available Telah dilakukan analisis iradiasi fluens neutron cepat terhadap berilium reflektor reaktor RSG-GAS. Analisis dilakukan dengan cara melakukan pengukuran fluks neutron di posisi berilium elemen dan berilium blok yang berfungsi sebagai reflector. Selanjutnya dilakukan perhitungan untuk menentukan apakah ada pengaruh fluens neutron selama berilium berada di teras reaktor. Selain cara tersebut dilakukan pula visualisasi untuk memastikan ada tidaknya deformasi pada berilium akibat iradiasi. Hasil pengukuran fluks dan fluens neutron cepat maksimal pada daya 200 kW untuk berilium elemen posisi E-2 sebesar 2,30E+07 n/cm2s dan 4,19E+17 n/cm2, J-8 sebesar 3,70E+07 n/cm2s dan 6,74E+17 n/cm2. Hasil pengukutan pada posisi B-3 sebesar 2,19E+12 n/cm2s dan 3,99E+22 n/cm2, G-10 sebesar 2,12E+12 n/cm2s dan 3,86E+22 n/cm2, serta berilium blok posisi (5-6 sebesar 5,02E+07 n/cm2s dan 9,15E+17 n/cm2, (C-D sebesar 2,32E+07 n/cm2s dan 4,23E+17 n/cm2. Deformasi yang diperoleh untuk berilium elemen (∆L/L posisi E-2 sebesar 1,12E-08, J-8 sebesar 1,84E-08, B-3 sebesar 1,60E-03, posisi G-10 sebesar 1,55E-03, sedangkan pada berilium blok di posisi 5-6 sebesar 2,52E-08 dan C-D sebesar 1,13E-08. Dari hasil ini disimpulkan tidak terjadi deformasi pada berilium elemen dan berilium blok. Hasil ini dibuktikan pula dari pengamatan visual, dimana tidak terlihat adanya deformasi pada berilium tersebut. Kata kunci : fluks, fluens, berilium elemen, berilium blok   Analysis of influence fast neutron fluence irradiated to the RSG-GAS beryllium reflector have been done. Methods of analysis was carried out by measuring fluxs neutron in beryllium element and block positio that function as reflector. The calculation done for determination it is there any influence of neutron as long as beryllium in the core. Bisede that, visualization done to make sure it there is any deformation at beryllium as efect of irradiation. Fluxs and fluences of beryllium element measurement result in 200 k

  3. Single-electron tunneling in InP nanowires

    NARCIS (Netherlands)

    De Franceschi, S.; Van Dam, J.A.; Bakkers, E.P.A.M.; Feiner, L.F.; Gurevich, L.; Kouwenhoven, P.

    2003-01-01

    We report on the fabrication and electrical characterization of field-effect devices based on wire-shaped InP crystals grown from Au catalyst particles by a vapor–liquid–solid process. Our InP wires are n-type doped with diameters in the 40–55-nm range and lengths of several micrometers. After being

  4. PEMODELAN KOLIMATOR DI RADIAL BEAM PORT REAKTOR KARTINI UNTUK BORON NEUTRON CAPTURE THERAPY

    Directory of Open Access Journals (Sweden)

    Bemby Yulio Vallenry

    2015-03-01

    Full Text Available Salah satu metode terapi kanker adalah Boron Neutron Capture Therapy (BNCT. BNCT memanfaatkan tangkapan neutron oleh 10B yang terendapkan pada sel kanker. Keunggulan BNCT dibandingkan dengan terapi radiasi lainnya adalah tingkat selektivitas yang tinggi karena tingkatannya adalah sel. Pada penelitian ini dilakukan pemodelan kolimator di radial beamport reaktor Kartini sebagai dasar pemilihan material dan manufature kolimator sebagai sumber neutron untuk BNCT. Pemodelan ini dilakukan dengan simulasi menggunakan perangkat lunak Monte Carlo N-Particle versi 5 (MCNP 5. MCNP 5 adalah suatu paket program untuk memodelkan sekaligus menghitung masalah transpor partikel dengan mengikuti sejarah hidup neutron semenjak lahir, bertranspor pada bahan hingga akhirnya hilang karena mengalami reaksi penyerapan atau keluar dari sistem. Pemodelan ini menggunakan variasi material dan ukurannya agar menghasilkan nilai dari tiap parameter-parameter yang sesuai dengan rekomendasi I International Atomic Energy Agency (IAEA untuk BNCT, yaitu fluks neutron epitermal (Фepi > 9 n.cm-2.s-1, rasio antara laju dosis neutron cepat dan fluks neutron epitermal (Ḋf/Фepi 0,7. Berdasarkan hasil optimasi dari pemodelan ini, material dan ukuran penyusun kolimator yang didapatkan yaitu 0,75 cm Ni sebagai dinding kolimator, 22 cm Al sebagai moderator dan 4,5 cm Bi sebagai perisai gamma. Keluaran berkas radiasi yang dihasilkan dari pemodelan kolimator radial beamport yaitu Фepi = 5,25 x 106 n.cm-2s-1, Ḋf/Фepi =1,17 x 10-13 Gy.cm2.n-1, Ḋγ/Фepi = 1,70 x 10-12 Gy.cm2.n-1, Фth/Фepi = 1,51 dan J/Фepi = 0,731. Berdasarkan penelitian ini, hasil optimasi 5 parameter sebagai persyaratan kolimator untuk BNCT yang keluar dari radial beam port tidak sepenuhnya memenuhi kriteria yang direkomendasikan oleh IAEA sehingga perlu dilakukan penelitian lebih lanjut agar tercapainya persyaratan IAEA. Kata kunci: BNCT, radial beamport, MCNP 5, kolimator   One of the cancer therapy methods is

  5. Temperature Studies of Single InP Quantum Dots

    Science.gov (United States)

    1999-06-18

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012858 TITLE: Temperature Studies of Single InP Quantum Dots DISTRIBUTION...34 QWR/QD.07 St Petersburg, Russia, June 14-18, 1999 © 1999 loffe Institute Temperature studies of single InP quantum dots Valdry Zwiller, Mats-Erik...Information on the size and geometry of our self-assembled InP Quantum Dots grown on GamnP lattice matched to GaAs has been published elsewhere -I

  6. Pengaruh Laju Alir Inlet Reaktor MSL terhadap Reduksi BOD, COD, TSS, dan Minyak/Lemak Limbah Cair Industri Minyak Goreng

    Directory of Open Access Journals (Sweden)

    Salmariza Sy

    2017-06-01

    Full Text Available This research was conducted by treating edible oil industry wastewater used Multi Soil Layering (MSL method. The MSL reactor was built from a 200x120x200 cm concrete basin. Andisol soil was mixed with sawdust and fine charcoal at each ratio 5:1:1 based on dry weight as an impermeable layer. The flow rate variations were 250, 500, 1000, and 1500 L/m2.day. The observed pollutant parameters were BOD, COD, TSS, oil/fat, and pH. The results showed that MSL reactor was effective to decrease the pollutant content of edible oil industry wastewater. The reactor could reduce concentration of effluent parameters below standard except for oil/fat parameters at high flow rates. In the effluent was found BOD 0.66-14.22 mg/L, COD 5-69 mg/L, TSS 9-26 mg/L, and oil/fat 2-9 mg/L. The flow rate had an effect on reduction efficiency of BOD, COD, TSS, and oil/fat but did not effect pH as all flow rate could raise pH 6.37-6.95 became pH 6.99-7.24. The lower the flow rate the higher the reduction efficiency. The reduction efficiency at flow rates 250 and 1500 L/m2 days for BOD were 99% and 86%, COD were 96% and 71%, TSS were 88% and 77%, and oil/fat were 80% and 60%.ABSTRAK  Penelitian ini dilakukan dengan mengolah air limbah industri minyak goreng menggunakan metoda Multi Soil Layering (MSL. Reaktor MSL dibuat dari beton berbentuk bak ukuran 200x120x200 cm. Tanah andisol dicampur dengan serbuk gergaji dan arang halus pada rasio masing-masing 5:1:1 berdasarkan berat kering sebagai penyusun lapisan impermeable. Variasi laju alir yaitu 250, 500, 1000, dan 1500 L/m2.hari. Parameter pencemar yang dianalisis meliputi BOD, COD, TSS, minyak/lemak, dan pH. Hasil penelitian menunjukkan bahwa reaktor MSL sangat efektif untuk menurunkan kandungan zat pencemar limbah cair industri minyak goreng. Reaktor dapat mereduksi konsentrasi parameter outlet sampai dibawah baku mutu yang distandarkan kecuali untuk parameter miyak/lemak pada perlakuan laju alir tinggi. Pada effluen

  7. Lightweight InP Solar Cells for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation in this Phase II SBIR is the development of a technology which will enable the manufacture of a lightweight, low cost, high radiation resistance InP...

  8. Quantum size effects in InP inner film fiber

    Institute of Scientific and Technical Information of China (English)

    WANG Ting-yun; WANG Ke-xin; LU Jun

    2005-01-01

    Based on the semiconductor amplifiing properties and the structure of optical fiber wave guide an InP inner fiber is developed.The InP inner film fiber can be employed as a small size,broadband,and ultra-short fiber amplifier.The quantum size effects of the fiber are emphatically investigated in the work.Using the experimental data,we compare the effective mass approximation (EMA) with effective parameterization within the tight binding (EPTB) models for the accurate description of the quantum size effects in InP.The results show that the EPTB model provides an excellent description of band gap variation over a wide range of sizes.The Bohr diameter and the effective Rydberg energy of InP are calculated.Finally,the amplifiing properties of the InP inner film fiber are discussed due to the quantum size effects.

  9. Donor Behavior in High-Purity Epitaxial InP.

    Science.gov (United States)

    1980-10-02

    Thermodynamic Analysis of L InP and GaAs Deposition", Journal of Phyjsica Chemical Solids 36, 111, (1975). 17. 0. Levenspiel , "Chemical Reaction Engineering",r John Wiley and Sons, NY, NY, (1972).

  10. Lightweight InP Solar Cells for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation in this Phase I SBIR is the development of a technology which will enable the manufacture of a lightweight, low cost, InP based compound semiconductor...

  11. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

    Science.gov (United States)

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

    2009-01-01

    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  12. Deep level defects in high temperature annealed InP

    Institute of Scientific and Technical Information of China (English)

    DONG Zhiyuan; ZHAO Youwen; ZENG Yiping; DUAN Manlong; LIN Lanying

    2004-01-01

    Deep level defects in high temperature annealed semi-conducting InP have been studied by deep level transient spectroscopy (DLTS). There is obvious difference in the deep defects between as-grown InP, InP annealed in phosphorus ambient and iron phosphide ambient, as far as their quantity and concentration are concerned. Only two defects at 0.24 and 0.64 eV can be detected in InP annealed iniron phosphide ambient,while defects at 0.24, 0.42, 0.54 and 0.64 eV have been detected in InP annealed in phosphorus ambient, in contrast to two defects at 0.49 and 0.64 eV or one defect at 0.13eV in as-grown InP. A defect suppression phenomenon related to iron diffusion process has been observed. The formation mechanism and the nature of the defects have been discussed.

  13. InP tunable ring resonator filters

    Science.gov (United States)

    Tauke-Pedretti, A.; Vawter, G. A.; Skogen, E. J.; Peake, G.; Overberg, M.; Alford, C.; Torres, D.; Cajas, F.

    2013-03-01

    Optical channelizing filters with narrow linewidth are of interest for optical processing of microwave signals. Fabrication tolerances make it difficult to place exactly the optical resonance frequency within the microwave spectrum as is required for many applications. Therefore, efficient tuning of the filter resonance is essential. In this paper we present a tunable ring resonator filter with an integrated semiconductor optical amplifier (SOA) fabricated on an InP based photonic integrated circuit (PIC) platform. The ring resonance is tuned over 37 GHz with just 0.2 mA of current injection into a passive phase section. The use of current injection is often more efficient than thermal tuning using heaters making them useful for low-power applications. The single active ring resonator has an electrical FWHM of 1.5 GHz and shows greater than 16 dB of extinction between on and off resonance. The effects of SOA internal ring gain and induced passive loss on extinction and linewidth will be shown. Agreement between experimentally demonstrated devices and simulations are shown. The integration of the active and passive regions is done using quantum well intermixing and the resonators utilize buried heterostructure waveguides. The fabrication process of these filters is compatible with the monolithic integration of DBR lasers and high speed modulators enabling single chip highly functional PICs for the channelizing of RF signals.

  14. PENGARUH KONSENTRASI ZrO2 TERHADAP KORELASI PERPINDAHAN PANAS NANOFLUIDA AIR-ZrO2 UNTUK PENDINGIN REAKTOR

    Directory of Open Access Journals (Sweden)

    K.A. Sudjatmi

    2015-03-01

    Full Text Available Sejalan dengan perkembangan konsep keselamatan pasif pada sistem keselamatan PLTN, maka sistem perpindahan panas konveksi alam memegang peranan penting. Pemakaian nanofluid sebagai fluida pendingin pada sistem keselamatan nuklir dapat digunakan pada Sistem Pendingin Teras Darurat dan Sistem Pendingin Pengungkung Luar Reaktor. Beberapa peneliti telah melakukan studi desain konseptual aplikasi nanofluid untuk meningkatkan keselamatan AP1000 dan sistem pendingin teras darurat pada reaktor daya eksperimen. Penerapan nanofluida juga mulai dikembangkan melalui hasil penelitian perpindahan panas konveksi alamiah pada sub-buluh dengan nanofluida sebagai fluida kerjanya sangat dibutuhkan. Penelitian ini bertujuan untuk menentukan pengaruh perubahan konsentrasi ZrO2 terhadap korelasi perpindahan panas konveksi alamiah dengan pendekatan eksperimental. Data eksperimental yang diperoleh digunakan untuk mengembangkan korelasi umum empirik perpindahan panas konveksi alamiah. Metode penelitian dengan menggunakan alat uji sub-buluh vertikal dengan geometri segitiga dan segiempat menggunakan air dan nanofluida air-ZrO2 sebagai fluida kerjanya. Konsentrasi nanopartikel dalam larutan yang digunakan sebesar 0,05 %, 0,10% dan 0,15 % dalam persen berat. Hasil penelitian menunjukan bahwa untuk bilangan Rayleigh yang sama, kemampuan pemindahan kalor oleh nanofluida air-ZrO2 lebih baik dari pada pemindahan kalor oleh air. Namun peningkatan konsentrasi nanofluida tidak selalu mendapatkan kemampuan pemindahan kalor yang lebih baik. Kata kunci: nanofluida air-ZrO2, konveksi alamiah, sub-buluh segitiga, sub-buluh segi segiempat   In line with the development of the passive safety concept for the safety systems of nuclear power plants, the natural convection heat transfer system plays an important role. The nanofluid as coolant fluid on nuclear safety system can be used in Emergency core cooling system and in reactor coolant system confinement. Several researchers have

  15. PENGGUNAAN TEKNOLOGI REAKTOR MICROBIAL FUEL CELLS (MFCs DALAM PENGOLAHAN LIMBAH CAIR INDUSTRI TAHU UNTUK MENGHASILKAN ENERGI LISTRIK

    Directory of Open Access Journals (Sweden)

    Purwono

    2015-09-01

    Full Text Available Microbial Fuel Cells (MFCs adalah bioreaktor yang mengubah energi kimia dari senyawa organik menjadi energi listrik melalui reaksi katalitik mikroorganisme dalam kondisi anaerob. Tujuan dari penelitian ini adalah mengetahui pengaruh variasi media terlekat (attached growth media dan variasi konsentrasi COD awal terhadap efisiensi penyisihan konsentrasi COD dan energi listrik yang dihasilkan. Reaktor MFCs didesain dalam betuk dual-chamber yang dihubungkan menggunakan jembatan garam. Kerikil dan bioball digunakan sebagi variasi media lekat pada kompartemen anoda dan konsentrasi limbah awal divariasikan dari 0%, 25%, 50%, dan 100% dari konsentrasi COD limbah cair industri tahu asli dengan cara melakukan pengenceran.Hasil penelitian menunjukkan bahwa media lekat kerikil dengan konsentrasi 50% menghasilkan arus listrik rata-rata tertinggi 7,25 µA dan energi listrik sebesar 179,54 mWh. Voltase dan enegi listrik pada kedua variasi tersebut semakin hari semakin enurun. Variasi konsentrasi 25%, 50%, dan 100% menghasilkan enurunan nilai effisiensi penyisihan COD masing-masing 41,41%; 39,90% dan 18,26%.Pada variasi 100% menghasilkan energi listrik lebih rendah dari pada 50%. Kemungkinan hal ini karena adanya senyawa sulfida yang berperan sebagai akseptor elektron. Pembentukan senyawa sulfida ditandai dengan terbentuknya warna hitam pada substrat. Efisiensi coulombic (εC akibat perbedaan media lekat dan variasi konsentrasi berada pada kisaran 0,001-0,035%. Rendahnya εC kemungkinan karena adanya produkproduk fermentasi dan biofilm pada elektroda anoda yang menghambat transfer elektron menuju elektroda anoda seperti biomassa, bahan organik terlarut, gas H2 dan gas CH4.

  16. Electron guns and collectors developed at INP for electron cooling devices

    Energy Technology Data Exchange (ETDEWEB)

    Sharapa, A.N.; Shemyakin, A.V. [Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-09-01

    Institute of Nuclear Physics (INP) has a rich experience in designing electron guns and collectors for electron cooling devices. This paper is a review of the experience of several INP research groups in this field. Some results obtained at INP for systems without a guiding magnetic field are also discussed.

  17. Absorption enhancement by textured InP in solar cells

    Science.gov (United States)

    Yun, Seokhun; Ji, Taeksoo

    2016-03-01

    III-V compound semiconductors seem to be the ideal materials for photovoltaic devices because they exhibit fast carrier velocity. III-V compound semiconductors, however, are unfavorable materials to be commercialized on large scale photovoltaic devices because of their high material cost. The textured surface shows the potential to increase the performance of solar cells because of the properties such as high absorption and longer light path length. These properties can overcome the disadvantage of the III-V compound semiconductors through thin thickness use when producing solar cells. In this study, we demonstrate that textured surfaces on InP formed by nano-sphere lithography and plasma etching process can enhance the absorption effectively in comparison with planar surface. The power conversion efficiency of InP solar cells using the textured InP and the aluminum doped zinc oxide was achieved up to 8%.

  18. InP concentrator solar cells for space applications

    Science.gov (United States)

    Ward, J. S.; Wanlass, M. W.; Coutts, T. J.; Emery, K. A.

    1991-01-01

    The design, fabrication, and characterization of high-performance, n(+)/p InP shallow-homojunction (SHJ) concentrator solar cells is described. The InP device structures were grown by atmospheric-pressure metalorganic vapor phase epitaxy (APMOVPE). A preliminary assessment of the effects of grid collection distance and emitter sheet resistance on cell performance is presented. At concentration ratios of over 100, cells with AM0 efficiencies in excess of 21 percent at 25 C and 19 percent at 80 C are reported. These results indicate that high-efficiency InP concentrator cells can be fabricated using existing technologies. The performance of these cells as a function of temperature is discussed, and areas for future improvement are outlined.

  19. InP Bulk Crystals Grown from Various Stoichiometric Melt

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    InP crystal was grown from stoichiometric or non-stoichiometric melt, including P-rich and In-rich condition by the P-injection synthesis LEC method. Owing to the non-stoichiometric condition, there are many pores in the tail of the P-rich ingot. Samples were characterized by high speed photoluminescence mapping and E.P.D. mapping. The perfection (dislocation, stoichiometry and uniformity) of these samples were studied and compared. The PL peak intensity standard deviation of the 4-inch InP wafer is higher. The EPDs around the pores are higher than the other regions. Besides the stress releasing, the pores and the high concentration of dislocations around them are the leading factors causing the inhomogeneity of the wafer. By adjusting the thermal field and ensuring the chemical stoichiometry, InP crystals of larger diameters and better performance can be developed.

  20. Palladium nanoparticles on InP for hydrogen detection

    Directory of Open Access Journals (Sweden)

    Zdansky Karel

    2011-01-01

    Full Text Available Abstract Layers of palladium (Pd nanoparticles on indium phosphide (InP were prepared by electrophoretic deposition from the colloid solution of Pd nanoparticles. Layers prepared by an opposite polarity of deposition showed different physical and morphological properties. Particles in solution are separated and, after deposition onto the InP surface, they form small aggregates. The size of the aggregates is dependent on the time of deposition. If the aggregates are small, the layer has no lateral conductance. Forward and reverse I-V characteristics showed a high rectification ratio with a high Schottky barrier height. The response of the structure on the presence of hydrogen was monitored.

  1. Solvothermal synthesis of InP quantum dots.

    Science.gov (United States)

    Nag, Angshuman; Sarma, D D

    2009-09-01

    We report an efficient and fast solvothermal route to prepare highly crystalline monodispersed InP quantum dots. This solvothermal route, not only ensures inert atmosphere, which is strictly required for the synthesis of phase pure InP quantum dots but also allows a reaction temperature as high as 430 degrees C, which is otherwise impossible to achieve using a typical solution chemistry; the higher reaction temperature makes the reaction more facile. This method also has a judicious control over the size of the quantum dots and thus in tuning the bandgap.

  2. Reactor for biological elimination of poorly degradable hydrocarbons by adjustment of substrate-specific retention times; Reaktor zur biologischen Eliminierung schwer abbaubarer Kohlenwasserstoffe durch Einstellung substratspezifischer Verweilzeiten

    Energy Technology Data Exchange (ETDEWEB)

    Brambach, R.

    1997-11-01

    Industrial waste water cleaning increasingly makes use of biological processes based on immobilized biomass, in order to ensure the aimed elimination of toxic substances. A novel, efficient reactor technique was developed, by which dangerous, poorly degradable dissolved hydrocarbons are selectively retained in the bioreactor thanks to an integrated membrane, while other substances are quickly discharged from the system via the effluent. With a synthetic waste water, this selective retention method achieved substrate-specific retention times which were five to fifty times higher than those of a merely hydrodynamically operated reactor system. In addition, the decoupling of high reactor and low effluent concentrations results in a higher biochemical activity in the reactor in comparison with conventional process techniques. (orig.) [Deutsch] In der industriellen Abwasserreinigung werden verstaerkt Bioverfahrenstechniken mit immobilisierter Biomasse eingesetzt, um eine gezielte Eliminierung gefaehrlicher Stoffe durchzufuehren. - Hierzu wurde eine neuartige leistungsfaehige Reaktortechnik entwickelt, die mittels einer im Bioreaktor integrierten Membran gefaehrliche, schwer abbaubare geloeste Kohlenwasserstoffe selektiv im Bioreaktor zurueckhaelt, waehrend andere Stoffe das System schnell ueber den Ablauf verlassen. Durch den stoffselektiven Rueckhalt wurden an einem synthetischen Abwasser substratspezifische Verweilzeiten erzielt, die um den Faktor 5 bis 50 ueber denen eines rein hydrodynamisch bestimmten Reaktorsystems liegen. Darueber hinaus wird aufgrund der Entkopplung von hoher Reaktor- und niedriger Ablaufkonzentration eine im Vergleich zu herkoemmlichen Verfahrenstechniken hoehere biochemische Aktivitaet im Reaktor erzielt. (orig.)

  3. Switching dynamics in InP photonic-crystal nanocavity

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel;

    2016-01-01

    In this paper, we presented switching dynamic investigations on an InP photonic-crystal (PhC) nanocavity structure using homodyne pump-probe measurements. The measurements were compared with simulations based on temporal nonlinear coupled mode theory and carrier rate equations for the dynamics...

  4. 2D InP photonic crystal fabrication process development

    NARCIS (Netherlands)

    Rong, B.; Van der Drift, E.; Van der Heijden, R.W.; Salemink, H.W.M.

    2006-01-01

    We have developed a reliable process to fabricate high quality 2D air-hole and dielectric column InP photonic crystals with a high aspect ratio on a STS production tool using ICP N2+Cl2 plasma. The photonic crystals have a triangular lattice with lattice constant of 400 nm and air-hole and dielectri

  5. Surface Plasmons on Highly Doped InP

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Ottaviano, Luisa; Semenova, Elizaveta

    2016-01-01

    Silicon doped InP is grown by metal-organic vapor phase epitaxy (MOVPE) using optimized growth parameters to achieve high free carrier concentration. Reflectance of the grown sample in mid-IR range is measured using FTIR and the result is used to retrieve the parameters of the dielectric function...

  6. Experiences with digital processing of images at INPE

    Science.gov (United States)

    Mascarenhas, N. D. A. (Principal Investigator)

    1984-01-01

    Four different research experiments with digital image processing at INPE will be described: (1) edge detection by hypothesis testing; (2) image interpolation by finite impulse response filters; (3) spatial feature extraction methods in multispectral classification; and (4) translational image registration by sequential tests of hypotheses.

  7. c-Myc inhibits TP53INP1 expression via promoter methylation in esophageal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Wenhao; Yang, Qinyuan [Department of Laboratory Medicine, Shanghai Tenth People' s Hospital, Tongji University School of Medicine, Shanghai 200072 (China); Huang, Miaolong [Department of Thoracic Surgery, Yuebei People' s Hospital, Shaoguan, Guangdong 512026 (China); Qiao, Yongxia [Department of Preventive Medicine, Tongji University, Shanghai City 200092 (China); Xie, Yuan; Yu, Yongchun [Department of Laboratory Medicine, Shanghai Tenth People' s Hospital, Tongji University School of Medicine, Shanghai 200072 (China); Jing, An, E-mail: Anjing77@gmail.com [Department of Thoracic Surgery, Yuebei People' s Hospital, Shaoguan, Guangdong 512026 (China); Institute of Cancer Research, Southern Medical University, Guangzhou 510515 (China); Li, Zhi, E-mail: lizhiweng2010@163.com [Department of Laboratory Medicine, Shanghai Tenth People' s Hospital, Tongji University School of Medicine, Shanghai 200072 (China)

    2011-02-11

    Research highlights: {yields} TP53INP1 expression is down-regulated in esophageal carcinoma and is associated with CGI-131 methylation. {yields} Inhibition of CGI-131 methylation upregulates TP53INP1 expression in ESCC cell lines. {yields} Ectopic expression of TP53INP1 inhibits growth of ESCC cells by inducing apoptosis and inhibiting cell cycle progression. {yields} c-Myc binds to the promoter of TP53INP1 in vivo and vitro and recruits DNMT3A to TP53INP1 promoter for CGI-131 methylation. -- Abstract: Tumor protein p53-induced nuclear protein 1 (TP53INP1) is a well known stress-induced protein that plays a role in both cell cycle arrest and p53-mediated apoptosis. Loss of TP53INP1 expression has been reported in human melanoma, breast carcinoma, and gastric cancer. However, TP53INP1 expression and its regulatory mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Our findings are in agreement with previous reports in that the expression of TP53INP1 was downregulated in 28% (10/36 cases) of ESCC lesions, and this was accompanied by significant promoter methylation. Overexpression of TP53INP1 induced G1 cell cycle arrest and increased apoptosis in ESCC cell lines (EC-1, EC-109, EC-9706). Furthermore, our study showed that the oncoprotein c-Myc bound to the core promoter of TP53INP1 and recruited DNA methyltransferase 3A to methylate the local promoter region, leading to the inhibition of TP53INP1 expression. Our findings revealed that TP53INP1 is a tumor suppressor in ESCC and that c-Myc-mediated DNA methylation-associated silencing of TP53INP1 contributed to the pathogenesis of human ESCC.

  8. PENENTUAN KANDUNGAN UNSUR PADA INSTALASI PENGOLAHAN AIR LIMBAH (IPAL RSUP DR. SOERADJI TIRTONEGORO KLATEN DENGAN METODE ANALISIS AKTIVASI NEUTRON REAKTOR KARTINI

    Directory of Open Access Journals (Sweden)

    - Niati

    2012-01-01

    Full Text Available Limbah cair hasil aktivasi manusia misalnya di Rumah Sakit harus diolah terlebih dahulu sebelum dialirkan ke lingkungan. Pengolahan limbah cair ini dilakukan untuk mengantisipasi adanya suatu hal yang berbahaya atau tidak aman bagi lingkungan. Permasalahan yang dikaji adalah dengan mengetahui jenis unsur dan kadarnya apakah melebihi dari batas kadar baku mutu limbah dan air minum. Metode  Analisis Aktivasi Neutron (AAN untuk analisis kualitatif yaitu mengetahui jenis unsur dan analisis kuantitatif yaitu menghitung kadar dari jenis unsur tersebut. Sampel limbah cair diaktivasi menggunakan sumber neutron dari Reaktor Kartini, kemudian dicacah menggunakan Spektrometri-γ, barulah analisis kualitatif dan kuantitatif dapat dilakukan. Hasil penelitian sampel air sumur dan limbah cair RS secara kualitatif terdapat jenis unsur dengan waktu peluruhan pendek seperti : Fe, Cl, dan Al dan waktu peluruhan panjang terdapat jenis unsur Br dan Na. Secara kuantitatif untuk waktu peluruhan pendek dengan evaporasi kadar Cl antara (0,0849-3,01E-06 ppm, kadar Al antara (2,3197-3,9841E-07 ppm; tanpa evaporasi kadar Cl antara (0,65785-2,3197E-07 ppm, kadar Al antara (2,5113-2,7761E-09 ppm. Untuk waktu peluruhan panjang dengan evaporasi kadar Br antara (0,069846-1,9147E-04 ppm, kadar Na antara (0,8058-3,2544E-05 ppm; tanpa evaporasi kadar Br 5,031E-06 ppm, kadar Na antara (6,7857-8,3285E-07 ppm. Dari hasil penelitian tersebut dapat disimpulkan bahwa waktu peluruhan dan perbedaan perlakuan sampel mengakibatkan jenis unsur dan kadar unsur yang dihasilkan juga berbeda-beda. Berdasarkan penghitungan kadar jenis unsur dan setelah dibandingkan dengan kadar baku mutu limbah dan mutu air maka limbah cair RSUP Dr. Soeradji Tirtonegoro Klaten dalam batas aman apabila dibuang ke lingkungan dan air sumur tersebut juga aman untuk dikonsumsi. Kata kunci : Instalasi Pengolahan Air Limbah (IPAL, AAN, Reaktor Kartini

  9. APLIKASI TEKNIK AAN DI REAKTOR RSG-GAS PADA PENENTUAN UNSUR ESENSIAL DAN TOKSIK DI DALAM IKAN DAN PAKAN IKAN

    Directory of Open Access Journals (Sweden)

    Saeful Yusuf

    2015-03-01

    Full Text Available Pada makalah ini diuraikan tentang aplikasi teknik AAN (Analisis Aktivasi Neutron dalam penentuan konsentrasi unsur-unsur esensial dan cemaran yang terkandung di dalam beberapa spesies ikan dan pakan ikan. Unsur-unsur esensial yang terkandung dalam pakan ikan buatan juga dianalisis untuk mengetahui pengaruhnya terhadap ikan. Penentuan unsur menggunakan teknik AAN dengan metode perbandingan dan metode k0-AAN. Sampel diiradiasi di reaktor RSG-GAS yang memiliki fluks neutron thermal 5 x 1013 n.cm-2.s-1 pada daya 15 MW. Hasil penelitian menunjukkan bahwa 12 unsur di dalam 11 spesies ikan air laut dan air tawar telah ditentukan yaitu As, Br, Cr, Co, Cs, Fe, Hg, K, Na, Rb, Se and Zn. Konsentrasi cemaran As didalam ikan laut sudah melampaui batas maksimum 1 mg/kg, sedangkan konsentrasi cemaran Hg masih dibawah batas maksimum 0,5 mg/kg, baik untuk ikan laut maupun ikan air tawar. Unsur K dan Na merupakan unsur makroesensial sedangkan unsur Cr, Co, Fe, Se and Zn adalah termasuk unsur mikroesensial. Secara umum ditunjukkan bahwa kandungan mineral didalam ikan laut lebih tinggi konsentrasinya dibandingkan ikan air tawar. Br, Cs dan Rb merupakan unsur-unsur non esensial yang teridentifikasi dalam semua ikan yang dianalisis. Penelitian terhadap pakan ikan air tawar menunjukkan bahwa semua unsur yang teridentifikasi juga terdapat di dalam ikan laut dan ikan air tawar. Hal ini menunjukkan bahwa pakan ikan berkontribusi terhadap konsentrasi unsur di dalam ikan air tawar. Kata kunci : Analisis aktivasi neutron, unsur esensial, unsur cemaran, ikan, pakan ikan   This paper reported on the application of NAA (Neutron Activation Analysis Technique in the determination of the concentration of the essential and toxic elements in some species of fish and fish feed. Determination of elements using instrumental NAA technique with comparison and k0-INAA methods. Samples were irradiated in the RSG-GAS which has a thermal neutron flux  5.0E +13 ncm-2s-1. The results

  10. Surface characterization of InP using photoluminescence

    Science.gov (United States)

    Chang, R. R.; Iyer, R.; Lile, D. L.

    1987-01-01

    Photoluminescence (PL) measurements have been performed on InP samples in situ during various surface treatments including chemical etching, wet anodization, and low-pressure chemical vapor deposition. It was found, in agreement with previously published results, that the magnitude of the PL signal varies markedly with surface treatment due presumably to changes in either surface-state density, and/or surface potential. In an attempt to assess the effectiveness of this noninvasive method as a tool for characterizing and monitoring the progressive development of a semiconductor surface during processing, a number of experiments on InP have been performed. The results indicate that although some uncertainty may exist in assigning a mechanism for the PL change in any given experiment, the general trend appears to be that surface degradation results in a reduced signal. As a result, process steps which enhance the PL intensity are likely to be beneficial in the preparation of a high-quality interface.

  11. A single crystalline InP nanowire photodetector

    Science.gov (United States)

    Yan, Xin; Li, Bang; Wu, Yao; Zhang, Xia; Ren, Xiaomin

    2016-08-01

    Single crystalline nanowires are critical for achieving high-responsivity, high-speed, and low-noise nanoscale photodetectors. Here, we report a metal-semiconductor-metal photodetector based on a single crystalline InP nanowire. The nanowires are grown by a self-catalyzed method and exhibit stacking-fault-free zinc blende crystal structure. The nanowire exhibits a typical n-type semiconductor property and shows a low room temperature dark current of several hundred pA at moderate biases. A photoresponsivity of 6.8 A/W is obtained at a laser power density of 0.2 mW/cm2. This work demonstrates that single crystalline InP nanowires are good candidates for future optoelectronic device applications.

  12. Electron Spin Relaxation in Intrinsic Bulk InP Semiconductor

    CERN Document Server

    Ma, Hong; Wang, Lihua; Ma, Guohong

    2010-01-01

    Electron spin dynamics is studied by time resolved pump probe reflectivity (TRPPR) technique using the co- and counter-circularly polarized femtosecond pulses in intrinsic bulk Indium Phosphide (InP) crystal at room temperature and 70 K. The reflectivity change from bleaching into absorption enhancement is observed with increasing pump photon energy. This phenomenon can be explained in terms of the spin sensitive band filling and band gap renormalization effects. Although electron spin relaxation process at room temperature is much faster than that at 70K, carrier density dependence of electron spin relaxation shows similar tendency. With increasing carrier density, the electron spin relaxation time increases initially and then decreases after reaching a maximum value. Our experimental results agree well with the recent theoretical prediction and D'yakonov-Perel' mechanism is considered as a dominating contribution to the electron spin relaxation in intrinsic bulk InP semiconductor.

  13. Simulation of INPE's printed circuit laboratory production line

    Science.gov (United States)

    Torgogomes, Arthur

    1988-05-01

    The development of a tool intended to improve, plan, monitor, and control INPE's Printed Circuit Laboratory Production Line is presented. A manipulatable computer model was developed. The model simulates the behavior of the production line elements, when established demand is given. A discrete simulation model of stochastic nature was created departing from study and comprehension of technical and operational characteristics. The system was modeled encompassing physical and chronological dimensions. The computer model utilizes the GASP 4 language simulation. The source program for this language was worked out to make possible such an application. The model was tested and proved operational in a 6800 Burroughs computer. The major significant results that the model provides information on necessary time between an order placed with the Laboratory and the final product ready for delivery to the client; also statistics of waiting time elapsed and starting time for production. Currently, this program is operational. It is being successfully utilized by INPE's Printed Laboratory Production Line.

  14. Azimuthally polarized cathodoluminescence from InP nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Brenny, B. J. M.; Osorio, C. I.; Polman, A., E-mail: polman@amolf.nl [Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); Dam, D. van [COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Gómez Rivas, J. [COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); FOM Institute DIFFER, P.O. Box 6336, 5600 HH Eindhoven (Netherlands)

    2015-11-16

    We determine the angle and polarization dependent emission from 1.75 µm and 2.50 µm long InP nanowires by using cathodoluminescence polarimetry. We excite the vertical wires using a 5 keV electron beam, and find that the 880 nm bandgap emission shows azimuthally polarized rings, with the number of rings depending on the wire height. The data agree well with a model in which spontaneous emission from the wire emitted into the far field interferes with emission reflected off the substrate. From the model, the depth range from which the emission is generated is found to be up to 400 nm below the top surface of the wires, well beyond the extent of the primary electron cloud. This enables a probe of the carrier diffusion length in the InP nanowires.

  15. Quantum confinement of excitons in wurtzite InP nanowires

    Science.gov (United States)

    Pemasiri, K.; Jackson, H. E.; Smith, L. M.; Wong, B. M.; Paiman, S.; Gao, Q.; Tan, H. H.; Jagadish, C.

    2015-05-01

    Exciton resonances are observed in photocurrent spectra of 80 nm wurtzite InP nanowire devices at low temperatures, which correspond to transitions between the A, B, and C valence bands and the lower conduction band. Photocurrent spectra for 30 nm WZ nanowires exhibit shifts of the exciton resonances to higher energy, which are consistent with finite element calculations of wavefunctions of the confined electrons and holes for the various bands.

  16. Surface processes during purification of InP quantum dots

    OpenAIRE

    2014-01-01

    Recently, a new simple and fast method for the synthesis of InP quantum dots by using phosphine as phosphorous precursor and myristic acid as surface stabilizer was reported. Purification after synthesis is necessary to obtain samples with good optical properties. Two methods of purification were compared and the surface processes which occur during purification were studied. Traditional precipitation with acetone is accompanied by a small increase in photoluminescence. It occurs that during ...

  17. Mechanistic Insights into the Formation of InP Quantum Dots**

    Science.gov (United States)

    Allen, Peter M.; Walker, Brian J.

    2011-01-01

    This paper examines the molecular mechanism of InP colloidal quantum dot (QD) syntheses. Unlike methods for monodisperse PbSe and CdSe we found that existing InP syntheses result in total depletion of molecular phosphorous species following nucleation, so QD growth is due exclusively to non-molecular ripening. We find that amines inhibit precursor depletion via solvation, and these findings may lead to better synthetic methodology for InP QDs. PMID:20025010

  18. Fabrication of ordered arrays of InP microstructures by wet chemical etching with Au masks.

    Science.gov (United States)

    Su, G; Guo, Q; Palmer, R E

    2002-12-01

    Ordered arrays of InP microstructures have been fabricated on InP(001) substrates by wet chemical etching in aqueous HCl with patterned Au masks. The masks were produced by Au deposition through copper grids or a monolayer of polystyrene microspheres. Square InP mesas (20 x 20 microns) and pillars (approximately 100 nm in both diameter and height) were both produced and characterized by scanning electron microscopy and atomic force microscopy.

  19. [Characterizations of InP in terahertz region].

    Science.gov (United States)

    Zhang, Cai-Hong; Wang, Yuan-Yuan; Ma, Jin-Long; Jin, Biao-Bing; Xu, Wei-Wei; Kang, Lin; Chen, Jian; Wu, Pei-Heng

    2009-08-01

    Terahertz time-domain spectroscopy (THz-TDS), which directly measures the THz wave's temporal electric field, can give the amplitude and phase of the THz wave pulse simultaneously. THz-TDS is attracting more attention among scientists. InP with short carrier average collision time and low effective mass is growing up as one of the best photoconductive materials for emitting and detecting THz waves. An n-type InP of 0.35 omega x cm was characterized over the range from 0.2 to 4 THz at room temperature in the present paper with THz time-domain spectroscopy, which was placed in a closed box purged with dry nitrogen gas. Some THz optical properties, such as complex refractive index, dielectric constant, and conductivity, were extracted, based on more exact iterative method with new initial function. Drude model was also applied for simulation, which fitted well with the experimental results. Finally, the carrier average collision time, density and mobility of the InP were also characterized.

  20. Electrical properties of oxygen ion-implanted InP

    Science.gov (United States)

    He, L.; Anderson, W. A.

    1992-10-01

    The effect of oxygen ion implantation on defect levels and the electrical properties of undoped InP ( n-type) and Sn-doped InP have been investigated as a function of postimplant annealing at temperatures of 300 and 400° C. The surface interruption by ion bombardment was studied by a non-invasive optical technique—photoreflectance (PR) spectroscopy. Current-voltage (I-V) characterization and deep level transient spectros-copy (DLTS) were carried out. The free carrier compensation mechanism was studied from the microstructure behavior of defect levels associated with O+ implantation. Free carriers may be trapped in both residual and ion-bombardment-induced defect sites. Rapid thermal annealing (RTA) performed at different temperatures showed that if residual traps were removed by annealing, the compensation efficiency will be enhanced. Post-implant RTA treatment showed that at the higher temperature (400°C), trapped carriers may be re-excited, resulting in a weakened compensation. Comparing the results of undoped and Sn-doped InP indicated that the carrier compensation effect is substrate doping dependent.

  1. InP HEMT Integrated Circuits for Submillimeter Wave Radiometers in Earth Remote Sensing

    Science.gov (United States)

    Deal, William R.; Chattopadhyay, Goutam

    2012-01-01

    The operating frequency of InP integrated circuits has pushed well into the Submillimeter Wave frequency band, with amplification reported as high as 670 GHz. This paper provides an overview of current performance and potential application of InP HEMT to Submillimeter Wave radiometers for earth remote sensing.

  2. Silicon doped InP as an alternative plasmonic material for mid-infrared

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Han, Li; Christensen, Dennis Valbjørn;

    2016-01-01

    Silicon-doped InP is grown on top of semiinsulating iron-doped and sulfur-doped InP substrates by metalorganic vapor phase epitaxy (MOVPE), and the growth parameters are adjusted to obtain various free carrier concentrations from 1.05×1019 cm-3 up to 3.28×1019 cm-3. Midinfrared (IR) reflection sp...

  3. Lasers in InP generic photonic integration technology platforms

    Science.gov (United States)

    Latkowski, Sylwester; Lenstra, Daan

    2015-04-01

    A review is given of a number of lasers in a form of photonic integrated circuits realized on InP substrate using a generic integration approach. The potential of these photonic circuits lies in their compactness, low power consumption, and significant reduction of fabrication cost by realization in generic foundry runs. Generic integration platforms offer the possibility of realizing functionally advanced photonic circuits using combinations of just a few standardized and parameterized building blocks. This vibrant field opens new doors to innovative product development for SMEs as well as curiosity-driven research.

  4. Pembuatan Biodiesel Dari Minyak Kelapa Sawit Dengan Menggunakan Katalis Berpromotor Ganda Berpenyangga γ-Alumina (CaO/KI/γ-Al2O3 Dalam Reaktor Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Sunu R Puspitaningati

    2013-09-01

    Full Text Available Biodiesel merupakan salah satu energi alternatif pengganti bahan bakar fosil dari hasil reaksi transesterifikasi minyak nabati dengan metanol. Proses pembuatan biodiesel selama ini menggunakan katalis homogen NaOH atau KOH yang memiliki kelemahan terbentuknya produk samping berupa sabun dan rumitnya pemisahan produk biodiesel dengan katalis. Maka dari itu, mulai dikembangkan penggunaan katalis heterogen untuk menggantikan penggunaan katalis homogen. Penelitian ini mengembangkan katalis CaO/KIγ-Al2O3­. Pembuatan katalis melalui metode presipitasi CaO pada γ-Al2O3 serta asam asetat sebagai larutan precursor selama 3 jam lalu impregnasi KI selama 3 jam. Kemudian, dioven selama 12 jam pada suhu 110oC dan dikalsinasi pada suhu 650oC selama 4,5 jam. Katalis yang diperoleh digunakan untuk membantu proses transesterifikasi biodiesel dengan variable massa katalis, rasio molar minyak dan metanol, dan suhu. Dari hasil penelitian didapatkan bahwa biodiesel dapat diproduksi melalui reaksi transesterifikasi menggunakan katalis CaO/KI/γ-Al2O3­ dalam reaktor fluidized bed. Kemurnian tertinggi dari biodiesel yang didapatkan yaitu sebesar 99,17%. Yield dan konversi tertinggi sebesar 97,19% dan 96,89%  didapatkan pada penggunaan massa katalis 16 gram dan rasio molar minyak dan metanol 1 : 36 serta kondisi operasi suhu 225oC dan laju alir umpan 6 ml/menit (waktu tinggal 8 jam memiliki densitas sebesar 0,853 gr/ml serta viskositas sebesar 5,53 mm2/s (cSt.

  5. Segregation of antimony in InP in MOVPE

    Energy Technology Data Exchange (ETDEWEB)

    Weeke, Stefan

    2008-07-01

    In this work the segregation of antimony in indium phosphide in metal organic vapour phase epitaxy (MOVPE)was systematically investigated. Therefore phosphine stabilized InP surfaces were treated with tri-methyl-antimony (TMSb) in MOVPE. An antimony rich Sb/InP surface was established, showing a typical spectra for the antimonides observed in reflectance anisotropy spectroscopy (RAS).Adsorption and desorption of antimony are investigated, as well as the incorporation of Sb during overgrowth of the Sb/InP surface with InP. Therefore the growth parameters temperature, TMSb partial pressure and treatment time are varied and their influence investigated. The experiments are monitored in-situ with RAS, the achieved data is correlated with ex-situ characterisation such as X-ray diffraction (XRD) and secondary ion mass spectroscopy (SIMS). It is shown that under treatment with TMSb a stable Sb/InP surface is formed within seconds, which does not change under further TMSb treatment. This process is rarely influenced by the TMSb partial pressure. On the contrary, the desorption of Sb is a very slow process. Two main processes can be distinguished: The desorption of excess Sb from the surface and the formation of the MOVPE prepared InP (2 x 1) surface. The reaction velocity of adsorption and desorption increases with temperature. Above a critical value the increase of TMSb partial pressure has no influence on the time for desorption. During overgrowth of the Sb/InP surface the opposite temperature dependence is observed: with increasing growth temperature the typical spectra for antimonides is observed longer. An analysis of the grown samples with XRD and SIMS showed the formation of an InPSb double quantum well. One layer is formed at the interface, the second one 50 nm-120 nm deep in the InP. The location of the 2nd InPSb layer can be correlated with the vanishing of the Sb signature in RAS. The distance between the quantum wells increases with growth temperature, until it

  6. Undoped semi-insulating indium phosphide (InP) and its applications

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ During the past several years, the research and development of InP material has made great progress due to serving as the substrate for most optoelectronic devices operating at the communications wavelength of 1.31 and 1.55 (m. At present, InP has become an important semiconductor material together with Si and GaAs. When compared to GaAs, InP has higher electron velocity, higher radiation hardness and better heat-conducting property. The advantage of InP crystal material allows higher frequency operation and lower power requirements. Therefore, InPis widely being used for the manufacture of microwave devices, high-frequency devices and optoelectronic integrated circuits (OEICs) which are indispensable for wireless technology, satellite communications[1-3]. Although n-type and p-type InP can meet actual needs, semi-insulating InP substrates remain to be improved due to their poor uniformity and consistency. For this reason, several possible approaches have been reported to the preparation of SI InP by wafer annealing under different conditions[4-9].

  7. Highly doped InP as a low loss plasmonic material for mid-IR region

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Takayama, Osamu; Morozov, S. V.

    2016-01-01

    We study plasmonic properties of highly doped InP in the mid-infrared (IR) range. InP was grown by metal-organic vapor phase epitaxy (MOVPE) with the growth conditions optimized to achieve high free electron concentrations by doping with silicon. The permittivity of the grown material was found...... by the excitation of surface plasmon-polaritons in a periodically structured epilayer. Characterization shows good agreement between the theory and experimental results and confirms that highly doped InP is an effective plasmonic material aiming it for applications in the mid-IR wavelength range....

  8. Systems and methods for advanced ultra-high-performance InP solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wanlass, Mark

    2017-03-07

    Systems and Methods for Advanced Ultra-High-Performance InP Solar Cells are provided. In one embodiment, an InP photovoltaic device comprises: a p-n junction absorber layer comprising at least one InP layer; a front surface confinement layer; and a back surface confinement layer; wherein either the front surface confinement layer or the back surface confinement layer forms part of a High-Low (HL) doping architecture; and wherein either the front surface confinement layer or the back surface confinement layer forms part of a heterointerface system architecture.

  9. [Managment system in safety and health at work organization. An Italian example in public sector: Inps].

    Science.gov (United States)

    Di Loreto, G; Felicioli, G

    2010-01-01

    The Istituto Nazionale della Previdenza Sociale (Inps) is one of the biggest Public Sector organizations in Italy; about 30.000 people work in his structures. Fifteen years ago, Inps launched a long term project with the objective to create a complex and efficient safety and health at work organization. Italian law contemplates a specific kind of physician working on safety and health at work, called "Medico competente", and 85 Inps's physicians work also as "Medico competente". This work describes how IT improved coordination and efficiency in this occupational health's management system.

  10. Preliminary design of the INPE's Solar Vector Magnetograph

    CERN Document Server

    Vieira, L E A; Lago, A Dal; Wrasse, C; Echer, E; Guarnieri, F L; Cardoso, F Reis; Guerrero, G; Costa, J Rezende; Palacios, J; Balmaceda, L; Alves, L Ribeiro; da Silva, L; Costa, L L; Sampaio, M; Soares, M C Rabello; Barbosa, M; Domingues, M; Rigozo, N; Mendes, O; Jauer, P; Dallaqua, R; Branco, R H; Stekel, T; Gonzalez, W; Kabata, W

    2016-01-01

    We describe the preliminary design of a magnetograph and visible-light imager instrument to study the solar dynamo processes through observations of the solar surface magnetic field distribution. The instrument will provide measurements of the vector magnetic field and of the line-of-sight velocity in the solar photosphere. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the heliosphere, the development of this instrument plays an important role in reaching the scientific goals of The Atmospheric and Space Science Coordination (CEA) at the Brazilian National Institute for Space Research (INPE). In particular, the CEA's space weather program will benefit most from the development of this technology. We expect that this project will be the starting point to establish a strong research program on Solar Physics in Brazil. Our main aim is acquiring progressively the know-how to build state-of-art sol...

  11. Photoluminescence of ingaas/inp grown by molecular beam epitaxy

    Directory of Open Access Journals (Sweden)

    Harmand Jean Christophe

    2004-01-01

    Full Text Available Photoluminescence (PL measurements due to temperature and excitation power were carried out in as function of sample containing a In0,53Ga0,47. As layer, grown by Molecular Beam Epitaxy on an InP substrate. The origins of the several luminescence processes observed at low temperature were determined by studying their different behaviors with increasing temperature and excitation power and by comparing the results with the data found in the literature. The following transitions have been identified: one transition involving localized excitons and two transitions involving acceptor impurities. A review of the main works published in the literature related to the optical transitions observed at low temperature in InGaAs/InP is also presented.

  12. Electrical detection of spin hyperpolarization in InP

    Science.gov (United States)

    Caspers, Christian; Ansermet, Jean-Philippe

    2014-09-01

    The electrical detection of surface spin polarization in Indium Phosphide (InP) is demonstrated. Using a planar four-terminal architecture on top of semi-insulating Fe:InP (001) wafers, optical orientation is separated from electrical detection. Spin filter tunnel contacts consisting of InP/oxide/Co reveal significant asymmetries in the differential resistance upon helicity change of the optical pumping. The iron-rich tunnel oxide provides the main spin selection mechanism. A reproducible helicity-dependent asymmetry as high as 18% could be observed at T = 55 K and an external induction field μ0H = 1 T. At room temperature and zero external field, a helicity-dependent asymmetry of 6% suggests the stand-alone applicability of the device either as an electronic spin sensor or as an optical helicity sensor.

  13. Electrical detection of spin hyperpolarization in InP

    Energy Technology Data Exchange (ETDEWEB)

    Caspers, Christian; Ansermet, Jean-Philippe [Laboratoire de Physique des Matériaux Nanostructurés, École Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne (Switzerland)

    2014-09-29

    The electrical detection of surface spin polarization in Indium Phosphide (InP) is demonstrated. Using a planar four-terminal architecture on top of semi-insulating Fe:InP (001) wafers, optical orientation is separated from electrical detection. Spin filter tunnel contacts consisting of InP/oxide/Co reveal significant asymmetries in the differential resistance upon helicity change of the optical pumping. The iron-rich tunnel oxide provides the main spin selection mechanism. A reproducible helicity-dependent asymmetry as high as 18% could be observed at T = 55 K and an external induction field μ{sub 0}H = 1 T. At room temperature and zero external field, a helicity-dependent asymmetry of 6% suggests the stand-alone applicability of the device either as an electronic spin sensor or as an optical helicity sensor.

  14. Extended Wavelength InP Based Avalanche Diodes for MWIR Response Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For this NASA STTR program, we propose to develop a novel superlattice-based near infrared to midwave infrared avalanche photodetector (APD) grown on InP substrates...

  15. Wurtzite-Phased InP Micropillars Grown on Silicon with Low Surface Recombination Velocity.

    Science.gov (United States)

    Li, Kun; Ng, Kar Wei; Tran, Thai-Truong D; Sun, Hao; Lu, Fanglu; Chang-Hasnain, Connie J

    2015-11-11

    The direct growth of III-V nanostructures on silicon has shown great promise in the integration of optoelectronics with silicon-based technologies. Our previous work showed that scaling up nanostructures to microsize while maintaining high quality heterogeneous integration opens a pathway toward a complete photonic integrated circuit and high-efficiency cost-effective solar cells. In this paper, we present a thorough material study of novel metastable InP micropillars monolithically grown on silicon, focusing on two enabling aspects of this technology-the stress relaxation mechanism at the heterogeneous interface and the microstructure surface quality. Aberration-corrected transmission electron microscopy studies show that InP grows directly on silicon without any amorphous layer in between. A set of periodic dislocations was found at the heterointerface, relaxing the 8% lattice mismatch between InP and Si. Single crystalline InP therefore can grow on top of the fully relaxed template, yielding high-quality micropillars with diameters expanding beyond 1 μm. An interesting power-dependence trend of carrier recombination lifetimes was captured for these InP micropillars at room temperature, for the first time for micro/nanostructures. By simply combining internal quantum efficiency with carrier lifetime, we revealed the recombination dynamics of nonradiative and radiative portions separately. A very low surface recombination velocity of 1.1 × 10(3) cm/sec was obtained. In addition, we experimentally estimated the radiative recombination B coefficient of 2.0 × 10(-10) cm(3)/sec for pure wurtzite-phased InP. These values are comparable with those obtained from InP bulk. Exceeding the limits of conventional nanowires, our InP micropillars combine the strengths of both nanostructures and bulk materials and will provide an avenue in heterogeneous integration of III-V semiconductor materials onto silicon platforms.

  16. Ultra-Fast Low Energy Switching Using an InP Photonic Crystal H0 Nanocavity

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel;

    2013-01-01

    Pump-probe measurements on InP photonic crystal H0 nanocavities show large-contrast ultrafast switching at low pulse energy. For large pulse energies, high-frequency carrier density oscillations are induced, leading to pulsesplitting.......Pump-probe measurements on InP photonic crystal H0 nanocavities show large-contrast ultrafast switching at low pulse energy. For large pulse energies, high-frequency carrier density oscillations are induced, leading to pulsesplitting....

  17. Structural analysis of erbium {delta}-doped InP by OMVPE with RBS-channeling

    Energy Technology Data Exchange (ETDEWEB)

    Yuhara, Junji; Takeda, Hitoshi; Matsubara, Naoki; Tabuchi, Masao; Fujiwara, Yasufumi; Morita, Kenji; Takeda, Yoshikazu [Nagoya Univ. (Japan). School of Engineering

    1997-03-01

    We have determined the lattice location of Er in InP {delta}-doped by OMVPE with RBS-channeling. Er concentrations along the <001> and <011> directions are same as random yields, while a significant flux peaking effect is seen for the <111> direction. These data suggest that Er atoms occupy the site equivalent to the hexahedral site in InP lattice. (author)

  18. 6-Mercaptohexanoic acid assisted synthesis of high quality InP quantum dots for optoelectronic applications

    Science.gov (United States)

    Mahmoud, Waleed E.; Chang, Y. C.; Al-Ghamdi, A. A.; Al-Marzouki, F.; Bronstein, Lyudmila M.

    2013-04-01

    Indium phosphide semiconductor quantum dots are of significant heed as their applications encompass a spacious concatenation in LEDs and solar cells technologies. For improving their serviceable prominence, there is a real demand for a fashion that furnishes prompt and large mass production of mightily monodispersed nanoparticles. This study conveys an efficacious and fast recipe of generating substantially monodispersed InP quantum dots via water based route technique using a novel surfactant. Herein, InP QDs have been prepared using 6-mercaptohexanoic acid for achieving an effective surface passivation of monodispersed InP QDs with highly luminescence at temperature 50 °C. The as prepared quantum dots were investigated by transmission electron microscopy, luminescence spectroscopy, and X-ray diffraction. The XRD depicted that the InP quantum dots have a cubic zinc blend structure. TEM image revealed that the prepared quantum dots are monodispersed and their average particle size of about 4 nm. Energy dispersive X-ray spectroscopy confirmed the existence of organic ligand as a shell around InP nanoparticles. Time resolved spectra depicted that the capping agent passivated the InP QDs surface and enhanced the luminescence emission.

  19. Preparation and optical properties of composite thin films with embedded InP nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    InP nanoparticles embedded in SiO2 thin films were prepared by radio-frequency magnetron co-sputtering. We analyzed the structure and growth behavior of the composite films under different preparation conditions. X-ray diffraction and Raman spectroscopy analyses indicate that InP nanoparticles have a polycrystalline structure. The aver-age size of InP nanoparticles is in the range of 3-10 nm. The broadening and red shift of the Raman peaks were observed,which can be interpreted by the phonon confinement model. Optical transmission spectra indicate that the optical absorp-tion edges of the films can be modulated in the visible light range. The marked blue shift of the absorption edge with respect to that of bulk InP is explained by the quantum con-finement effect. The theoretical values of the blue shift pre-dicted by the effective mass approximation model are differ-ent from the experimental results for the InP-SiO2 system. Analyses indicate that the exciton effective mass of the InP nanoparticles is not constant and is inverse relative to the particles radius,which may be the main reason that results in the discrepancy between the theoretical and the experi-mental result. We discussed the possible transition of the direct band gap to the indirect band gap for InP nanoparti-cles embedded in SiO2 thin films.

  20. Wafer-scale self-organized InP nanopillars with controlled orientation for photovoltaic devices.

    Science.gov (United States)

    Sanatinia, Reza; Berrier, Audrey; Dhaka, Veer; Perros, Alexander P; Huhtio, Teppo; Lipsanen, Harri; Anand, Srinivasan

    2015-10-16

    A unique wafer-scale self-organization process for generation of InP nanopillars is demonstrated, which is based on maskless ion-beam etching (IBE) of InP developed to obtain the nanopillars, where the height, shape, and orientation of the nanopillars can be varied by controlling the processing parameters. The fabricated InP nanopillars exhibit broadband suppression of the reflectance, 'black InP,' a property useful for solar cells. The realization of a conformal p-n junction for carrier collection, in the fabricated solar cells, is achieved by a metalorganic vapor phase epitaxy (MOVPE) overgrowth step on the fabricated pillars. The conformal overgrowth retains the broadband anti-reflection property of the InP nanopillars, indicating the feasibility of this technology for solar cells. Surface passivation of the formed InP nanopillars using sulfur-oleylamine solution resulted in improved solar-cell characteristics. An open-circuit voltage of 0.71 V and an increase of 0.13 V compared to the unpassivated device were achieved.

  1. Influence of catalyst droplet diameter on the growth direction of InP nanowires grown on Si(001) substrate

    Science.gov (United States)

    Naji, K.; Saint-Girons, G.; Penuelas, J.; Patriarche, G.; Largeau, L.; Dumont, H.; Rojo-Romeo, P.; Gendry, M.

    2013-06-01

    It is demonstrated that the growth direction of InP nanowires grown on (001)-oriented silicon substrate strongly depends on the diameter of the gold catalyst droplets. Small droplets with diameter less than about 15 nm lead to the formation of nanowires leaning on the {111} planes of the zinc blende InP seeds formed in the early stages of growth. Larger droplets lead to the formation of twins in the InP seeds and to the formation of nanowires leaning on the {111} planes of these twinned InP variants, inducing growth directions corresponding to the directions of the silicon substrate.

  2. Surface processes during purification of InP quantum dots

    Directory of Open Access Journals (Sweden)

    Natalia Mordvinova

    2014-08-01

    Full Text Available Recently, a new simple and fast method for the synthesis of InP quantum dots by using phosphine as phosphorous precursor and myristic acid as surface stabilizer was reported. Purification after synthesis is necessary to obtain samples with good optical properties. Two methods of purification were compared and the surface processes which occur during purification were studied. Traditional precipitation with acetone is accompanied by a small increase in photoluminescence. It occurs that during the purification the hydrolysis of the indium precursor takes place, which leads to a better surface passivation. The electrophoretic purification technique does not increase luminescence efficiency but yields very pure quantum dots in only a few minutes. Additionally, the formation of In(OH3 during the low temperature synthesis was explained. Purification of quantum dots is a very significant part of postsynthetical treatment that determines the properties of the material. But this subject is not sufficiently discussed in the literature. The paper is devoted to the processes that occur at the surface of quantum dots during purification. A new method of purification, electrophoresis, is investigated and described in particular.

  3. Surface processes during purification of InP quantum dots.

    Science.gov (United States)

    Mordvinova, Natalia; Emelin, Pavel; Vinokurov, Alexander; Dorofeev, Sergey; Abakumov, Artem; Kuznetsova, Tatiana

    2014-01-01

    Recently, a new simple and fast method for the synthesis of InP quantum dots by using phosphine as phosphorous precursor and myristic acid as surface stabilizer was reported. Purification after synthesis is necessary to obtain samples with good optical properties. Two methods of purification were compared and the surface processes which occur during purification were studied. Traditional precipitation with acetone is accompanied by a small increase in photoluminescence. It occurs that during the purification the hydrolysis of the indium precursor takes place, which leads to a better surface passivation. The electrophoretic purification technique does not increase luminescence efficiency but yields very pure quantum dots in only a few minutes. Additionally, the formation of In(OH)3 during the low temperature synthesis was explained. Purification of quantum dots is a very significant part of postsynthetical treatment that determines the properties of the material. But this subject is not sufficiently discussed in the literature. The paper is devoted to the processes that occur at the surface of quantum dots during purification. A new method of purification, electrophoresis, is investigated and described in particular.

  4. Single n+-i-n+ InP nanowires for highly sensitive terahertz detection

    Science.gov (United States)

    Peng, Kun; Parkinson, Patrick; Gao, Qian; Boland, Jessica L.; Li, Ziyuan; Wang, Fan; Mokkapati, Sudha; Fu, Lan; Johnston, Michael B.; Tan, Hark Hoe; Jagadish, Chennupati

    2017-03-01

    Developing single-nanowire terahertz (THz) electronics and employing them as sub-wavelength components for highly-integrated THz time-domain spectroscopy (THz-TDS) applications is a promising approach to achieve future low-cost, highly integrable and high-resolution THz tools, which are desirable in many areas spanning from security, industry, environmental monitoring and medical diagnostics to fundamental science. In this work, we present the design and growth of n+-i-n+ InP nanowires. The axial doping profile of the n+-i-n+ InP nanowires has been calibrated and characterized using combined optical and electrical approaches to achieve nanowire devices with low contact resistances, on which the highly-sensitive InP single-nanowire photoconductive THz detectors have been demonstrated. While the n+-i-n+ InP nanowire detector has a only pA-level response current, it has a 2.5 times improved signal-to-noise ratio compared with the undoped InP nanowire detector and is comparable to traditional bulk THz detectors. This performance indicates a promising path to nanowire-based THz electronics for future commercial applications.

  5. The salicylidene acylhydrazide INP0341 attenuates Pseudomonas aeruginosa virulence in vitro and in vivo.

    Science.gov (United States)

    Uusitalo, Pia; Hägglund, Ulrik; Rhöös, Elin; Scherman Norberg, Henrik; Elofsson, Mikael; Sundin, Charlotta

    2017-08-01

    Pseudomonas aeruginosa is an opportunistic pathogen that can be very hard to treat because of high resistance to different antibiotics and alternative treatment regimens are greatly needed. An alternative or a complement to traditional antibiotic is to inhibit virulence of the bacteria. The salicylidene acylhydrazide, INP0341, belongs to a class of compounds that has previously been shown to inhibit virulence in a number of Gram-negative bacteria. In this study, the virulence blocking effect of INP0341 on P. aeruginosa was studied in vitro and in vivo. Two important and closely related virulence system were examined, the type III secretion system (T3SS) that translocates virulence effectors into the cytosol of the host cell to evade immune defense and facilitate colonization and the flagella system, needed for motility and biofilm formation. INP0341 was shown to inhibit expression and secretion of the T3SS toxin exoenzyme S (ExoS) and to prevent bacterial motility on agar plates and biofilm formation. In addition, INP0341 showed an increased survival of P. aeruginosa-infected mice. In conclusion, INP0341 attenuates P. aeruginosa virulence.

  6. Photoluminescence study of as-grown vertically standing wurtzite InP nanowire ensembles.

    Science.gov (United States)

    Iqbal, Azhar; Beech, Jason P; Anttu, Nicklas; Pistol, Mats-Erik; Samuelson, Lars; Borgström, Magnus T; Yartsev, Arkady

    2013-03-22

    We demonstrate a method that enables the study of photoluminescence of as-grown nanowires on a native substrate by non-destructively suppressing the contribution of substrate photoluminescence. This is achieved by using polarized photo-excitation and photoluminescence and by making an appropriate choice of incident angle of both excitation beam and photoluminescence collection direction. Using TE-polarized excitation at a wavelength of 488 nm at an incident angle of ∼70° we suppress the InP substrate photoluminescence relative to that of the InP nanowires by about 80 times. Consequently, the photoluminescence originating from the nanowires becomes comparable to and easily distinguishable from the substrate photoluminescence. The measured photoluminescence, which peaks at photon energies of ∼1.35 eV and ∼1.49 eV, corresponds to the InP substrate with zinc-blende crystal structure and to the InP nanowires with wurtzite crystal structure, respectively. The photoluminescence quantum yield of the nanowires was found to be ∼20 times lower than that of the InP substrate. The nanowires, grown vertically in a random ensemble, neither exhibit substantial emission polarization selectivity to the axis of the nanowires nor follow excitation polarization preferences observed previously for a single nanowire.

  7. Differential InP HEMT MMIC Amplifiers Embedded in Waveguides

    Science.gov (United States)

    Kangaslahti, Pekka; Schlecht, Erich; Samoska, Lorene

    2009-01-01

    Monolithic microwave integrated-circuit (MMIC) amplifiers of a type now being developed for operation at frequencies of hundreds of gigahertz contain InP high-electron-mobility transistors (HEMTs) in a differential configuration. The differential configuration makes it possible to obtain gains greater than those of amplifiers having the single-ended configuration. To reduce losses associated with packaging, the MMIC chips are designed integrally with, and embedded in, waveguide packages, with the additional benefit that the packages are compact enough to fit into phased transmitting and/or receiving antenna arrays. Differential configurations (which are inherently balanced) have been used to extend the upper limits of operating frequencies of complementary metal oxide/semiconductor (CMOS) amplifiers to the microwave range but, until now, have not been applied in millimeter- wave amplifier circuits. Baluns have traditionally been used to transform from single-ended to balanced configurations, but baluns tend to be lossy. Instead of baluns, finlines are used to effect this transformation in the present line of development. Finlines have been used extensively to drive millimeter- wave mixers in balanced configurations. In the present extension of the finline balancing concept, finline transitions are integrated onto the affected MMICs (see figure). The differential configuration creates a virtual ground within each pair of InP HEMT gate fingers, eliminating the need for inductive vias to ground. Elimination of these vias greatly reduces parasitic components of current and the associated losses within an amplifier, thereby enabling more nearly complete utilization of the full performance of each transistor. The differential configuration offers the additional benefit of multiplying (relative to the single-ended configuration) the input and output impedances of each transistor by a factor of four, so that it is possible to use large transistors that would otherwise have

  8. Comparison of low-temperature oxides on polycrystalline InP by AES, SIMS and XPS

    Science.gov (United States)

    Kazmerski, L. L.; Ireland, P. J.; Sheldon, P.; Chu, T. L.; Chu, S. S.; Lin, C. L.

    1980-10-01

    Oxides and their interfaces with polycrystalline InP are examined using complementary high-resolution AES, SIMS and XPS. The oxides, grown by low-temperature dry and wet processes, are compared for composition and phase content. SIMS and AES depth-composition data are used to compare the uniformity of the oxide layers and the composition of the interfacial region. Confirmation of impurity accumulation at the oxide-InP interfaces is presented, including buildup of elemental P and InP dopant, S. Other impurities associated with the growth of the wet oxide are found to be localized at the interface. Some evidence of impurity accumulation at grain boundaries at the wet oxide-polycrystalline InP interface is provided by SIMS and EBIC.

  9. Twin and grain boundary in InP: A synchrotron radiation study

    Energy Technology Data Exchange (ETDEWEB)

    Han, Y.; Liu, X.; Jiao, J.; Lin, L. [Chinese Academy of Sciences, Beijing (China). Inst. of Semiconductors; Jiang, J.; Wang, Z.; Tian, Y. [Chinese Academy of Sciences, Beijing (China). Beijing Synchrotron Radiation Lab.

    1998-12-31

    Experimentally observed X-ray reflectivity curves show bi-crystal(twin) characteristics. The study revealed that there was defect segregation at the twin boundary. Stress was relaxed at the edge of the boundary. Relaxation of the stress resulted in formation of twin and other defects. As a result of formation of such defects, a defect-free and stress-free zone or low defect density and small stress zone is created around the defects. So a twin model was proposed to explain the experimental results. Stress(mainly thermal stress), chemical stoichiometry deviation and impurities nonhomogeneous distributions are the key factors that cause twins in LEC InP crystal growth. Twins on (111) face in LEC InP crystal were studied. Experimental evidence of above mentioned twin model and suggestions on how to get twin-free LEC InP single crystals will be discussed.

  10. Excitonic properties of wurtzite InP nanowires grown on silicon substrate

    Science.gov (United States)

    Alouane, M. H. Hadj; Chauvin, N.; Khmissi, H.; Naji, K.; Ilahi, B.; Maaref, H.; Patriarche, G.; Gendry, M.; Bru-Chevallier, C.

    2013-01-01

    In order to investigate the optical properties of wurtzite (Wz) InP nanowires grown on Si(001) by solid source molecular beam epitaxy with the vapour-liquid-solid method, the growth temperature and V/III pressure ratio have been optimized to remove any zinc-blende insertion. These pure Wz InP nanowires have been investigated by photoluminescence (PL), time-resolved PL and PL excitation. Direct observation of the second and third valence band in Wz InP nanowires using PL spectroscopy at high excitation power have been reported and, from these measurements, a crystal field splitting of 74 meV and a spin-orbit interaction energy of 145 meV were extracted. Based on the study of temperature-dependent optical properties, we have performed an investigation of the thermal escape processes of carriers and the electron-phonon coupling strength.

  11. Comparative Monte Carlo analysis of InP- and GaN-based Gunn diodes

    Science.gov (United States)

    García, S.; Pérez, S.; Íñiguez-de-la-Torre, I.; Mateos, J.; González, T.

    2014-01-01

    In this work, we report on Monte Carlo simulations to study the capability to generate Gunn oscillations of diodes based on InP and GaN with around 1 μm active region length. We compare the power spectral density of current sequences in diodes with and without notch for different lengths and two doping profiles. It is found that InP structures provide 400 GHz current oscillations for the fundamental harmonic in structures without notch and around 140 GHz in notched diodes. On the other hand, GaN diodes can operate up to 300 GHz for the fundamental harmonic, and when the notch is effective, a larger number of harmonics, reaching the Terahertz range, with higher spectral purity than in InP diodes are generated. Therefore, GaN-based diodes offer a high power alternative for sub-millimeter wave Gunn oscillations.

  12. Design and modeling of InP DHBT power amplifiers at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Yan, Lei; Johansen, Tom K.

    2012-01-01

    In this paper, the design and modeling of InP DHBT based millimeter-wave(mm-wave) power amplifiers is described. This includes the modeling of InP DHBT devices and layout parasitics. An EM-circuit co-simulation approach is described to allow all parasitics to be modeled for accurate circuit...... performance evaluation. A single-branch cascode based PA using single-finger InP DHBT devices shows a measured power gain of 9.2dB and a saturated output power of 12.3dBm at 67.2GHz. The output power at 1dB compression is 9.0dBm. A similar two-way combined cascode based PA using three-finger devices...

  13. Temperature and Thickness Effects on Electrical Properties of InP Films Deposited by Spray Pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Rcfik Kayah; Mehmet Ari; Mustafa Oztas; Metin Bedir; Funda Aksoy

    2009-01-01

    InP film samples are prepared by spray pyrolysis technique using aqueous solutions of InCl3 and Na2HPO4, which are atomized with compressed air as carrier gas onto glass substrates at 500 ℃ with different thicknesses of the films. The structural properties of the samples are determined by x-ray diffraction (XRD). It is found that the crystal structure of the InP films is polycrystailine hexagonal. The orientations of all the obtained films are along the c-axis perpendicular to the substrate. The electrical measurements of the samples are obtained by dc four-probe technique on rectangular-shape samples. The effects of temperature on the electrical properties of the InP films are studied in detail.

  14. InP on SOI devices for optical communication and optical network on chip

    Science.gov (United States)

    Fedeli, J.-M.; Ben Bakir, B.; Olivier, N.; Grosse, Ph.; Grenouillet, L.; Augendre, E.; Phillippe, P.; Gilbert, K.; Bordel, D.; Harduin, J.

    2011-01-01

    For about ten years, we have been developing InP on Si devices under different projects focusing first on μlasers then on semicompact lasers. For aiming the integration on a CMOS circuit and for thermal issue, we relied on SiO2 direct bonding of InP unpatterned materials. After the chemical removal of the InP substrate, the heterostructures lie on top of silicon waveguides of an SOI wafer with a separation of about 100nm. Different lasers or photodetectors have been achieved for off-chip optical communication and for intra-chip optical communication within an optical network. For high performance computing with high speed communication between cores, we developed InP microdisk lasers that are coupled to silicon waveguide and produced 100μW of optical power and that can be directly modulated up to 5G at different wavelengths. The optical network is based on wavelength selective circuits with ring resonators. InGaAs photodetectors are evanescently coupled to the silicon waveguide with an efficiency of 0.8A/W. The fabrication has been demonstrated at 200mm wafer scale in a microelectronics clean room for CMOS compatibility. For off-chip communication, silicon on InP evanescent laser have been realized with an innovative design where the cavity is defined in silicon and the gain localized in the QW of bonded InP hererostructure. The investigated devices operate at continuous wave regime with room temperature threshold current below 100 mA, the side mode suppression ratio is as high as 20dB, and the fibercoupled output power is {7mW. Direct modulation can be achieved with already 6G operation.

  15. Estimating the background covariance error for the Global Data Assimilation System of CPTEC/INPE

    Science.gov (United States)

    Bastarz, C. F.; Goncalves, L.

    2013-05-01

    The global data assimilation system at CPTEC/INPE, named G3Dvar is based in the Gridoint Statistical Interpolation (GSI/NCEP/GMAO) and in the general circulation model from that same center (GCM/CPTEC/INPE). The G3Dvar is a tri-dimensional variational data assimilation system that uses a Background Error Covariance Matrix (BE) fixed (in its current implementation, it uses the matrix from Global Forecast System - GFS/NCEP). The goal of this work is to present the preliminary results of the calculation of the new BE based on the GCM/CPTEC/INPE using a methodology similar to the one used for the GSI/WRFDA, called gen_be. The calculation is done in 5 distinct steps in the analysis increment space. (a) stream function and potential velocity are determined from the wind fields; (b) the mean of the stream function and potential velocity are calculated in order to obtain the perturbation fields for the remaing variables (streamfunction, potencial velocity, temperature, relative humidity and surface pressure); (c) the covariances of the perturbation fields, regression coeficients and balance between streamfunction, temperature and surface pressure are estimated. For this particular system, i.e. GCM/CPTEC/INPE, the necessity for constrains towards the statistical balance between streamfuncion and potential velocity, temperature and surface pressure will be evaluated as well as the how it affects the BE matrix calculation. Hence, this work will investigate the necessary procedures for calculating BE and show how does that differs from the standard calculation and how it is calibrated/adjusted based on the GCM/CPTEC/INPE. Results from a comparison between the main differences between the GFS BE and the newly calculated GCM/CPTEC/INPE BE are discussed in addition to an impact study using the different background error covariance matrices.

  16. InP based lasers and optical amplifiers with wire-/dot-like active regions

    DEFF Research Database (Denmark)

    Reithmaier, J. P.; Somers, A.; Deubert, S.

    2005-01-01

    Long wavelength lasers and semiconductor optical amplifiers based on InAs quantum wire/dot-like active regions were developed on InP substrates dedicated to cover the extended telecommunication wavelength range between 1.4 - 1.65 mm. In a brief overview different technological approaches will be ......Long wavelength lasers and semiconductor optical amplifiers based on InAs quantum wire/dot-like active regions were developed on InP substrates dedicated to cover the extended telecommunication wavelength range between 1.4 - 1.65 mm. In a brief overview different technological approaches...

  17. Design and fabrication of InP micro-ring resonant detectors

    Institute of Scientific and Technical Information of China (English)

    辛海明; 黄永清; 陈海波; 黄辉; 任晓敏; 周星光

    2009-01-01

    The quantum efficiency and the transient response of the InP semiconductor micro-ring resonant detector are analyzed to get the optimum design parameters.Then the side coupling micro-ring resonant is fabricated using the InP semiconductor material based on the parameters.The micro-ring resonant cavity has the raius of 80 μm,waveguide width of 3 μm and the coupler gap of 1 μm.The test results show that the FSR is 0.75 nm,and the FWHM is 0.5 nm,which are consistent with the theoretical calculation results.

  18. ANISOTROPIC RADIATIVE DECAY OF InP SELF-ASSEMBLED QUANTUM DOTS

    OpenAIRE

    1998-01-01

    Strong optical anisotropy of the photoluminescence (PL) spectra and time resolvedPL spectra is observed in InP self-assembled quantum dots (SADs) embedded inGaInP matrix. From the TEM study, the origin of the optical anisotropy appearsto be due to the formation of composition modulation planes in GaInP matrix.We also studied the size dependence of the radiative decay time. In the vicinityof the PL peak from InP SADs, slowdown of the PL decay time was observed ondecreasing the detection energy...

  19. Electronic and Vibrational Spectra of InP Quantum Dots Formed by Sequential Ion Implantation

    Science.gov (United States)

    Hall, C.; Mu, R.; Tung, Y. S.; Ueda, A.; Henderson, D. O.; White, C. W.

    1997-01-01

    We have performed sequential ion implantation of indium and phosphorus into silica combined with controlled thermal annealing to fabricate InP quantum dots in a dielectric host. Electronic and vibrational spectra were measured for the as-implanted and annealed samples. The annealed samples show a peak in the infrared spectra near 320/cm which is attributed to a surface phonon mode and is in good agreement with the value calculated from Frolich's theory of surface phonon polaritons. The electronic spectra show the development of a band near 390 nm that is attributed to quantum confined InP.

  20. Spin Quantum Beats in InP Quantum Dots in a Magnetic Field

    Science.gov (United States)

    2001-06-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP013252 TITLE: Spin Quantum Beats in InP Quantum Dots in a Magnetic Field...Technology" SRPN.05 St Petersburg, Russia, June 18-22, 2001 (0 2001 loffe Institute Spin quantum beats in InP quantum dots in a magnetic field L A... quantum dots . A detailed description of the structure is given in [ ]. The luminescence was excited by 3 ps pulses of a Ti:sapphire laser, 40 meV above

  1. Modeling on the size dependent properties of InP quantum dots: a hybrid functional study

    Science.gov (United States)

    Cho, Eunseog; Jang, Hyosook; Lee, Junho; Jang, Eunjoo

    2013-05-01

    Theoretical calculations based on density functional theory were performed to provide better understanding of the size dependent electronic properties of InP quantum dots (QDs). Using a hybrid functional approach, we suggest a reliable analytical equation to describe the change of energy band gap as a function of size. Synthesizing colloidal InP QDs with 2-4 nm diameter and measuring their optical properties was also carried out. It was found that the theoretical band gaps showed a linear dependence on the inverse size of QDs and gave energy band gaps almost identical to the experimental values.

  2. InP Gunn Diodes with Current Limiting Contact for High Efficiency Gunn Oscillators

    Science.gov (United States)

    Kim, Mi-Ra; Rhee, Jin-Koo; Lee, Chang-Woo; Chae, Yeon-Sik; Choi, Jae-Hyun; Kim, Wan-Joo

    We fabricated and examined current limiting effect for InP Gunn diodes with stable depletion layer mode operation of diodes for high efficiency Gunn oscillators. Current limiting at the cathode was achieved by a shallow Schottky barrier at the interface. We discussed fabrication procedure, the results for negative differential resistance and rf tests for InP Gunn diodes. It was shown that the fabricated Gunn diodes have the output power of 10.22dBm at a frequency of 90.13GHz. Its input voltage and corresponding current were 8.55V and 252mA, respectively.

  3. Self-assembly structure formation on patterned InP surfaces

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Self-assembly of polystyrene spheres guided by patterned n-type InP substrates has been investigated. InP surfaces were patterned using a variety of methods including wet chemical etching,sputter coating,thermal evaporation,and photo lithography. The self-assembly of polystyrene spheres depended on the appearance of patterns and was affected by the deposition techniques (sputter coating and thermal evaporation) of Au micro-squares. SEM and AFM were used to characterize the surface morphologies.

  4. AFM observation of OMVPE-grown ErP on InP substrates using a new organometal tris(ethylcyclopentadienyl)erbium (Er(EtCp){sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Akane, T.; Jinno, S.; Yang, Y.; Kuno, T.; Hirata, T.; Isogai, Y.; Watanabe, N.; Fujiwara, Y.; Nakamura, A.; Takeda, Y

    2003-06-30

    ErP has been grown on InP(0 0 1) substrates by organometallic vapor phase epitaxy (OMVPE) using a new liquid organic Er source: tris(ethylcyclopentadienyl)erbium (Er(EtCp){sub 3}). Morphological change of an ErP layer on InP(0 0 1) is investigated together with that of an overgrown capping InP layer. Optimum growth condition of InP causes islanding on over-monolayer-ErP. A relatively low overgrowth temperature of InP is a key factor for attaining complete capping coverage on ErP.

  5. Absence of tumor suppressor tumor protein 53-induced nuclear protein 1 (TP53INP1) sensitizes mouse thymocytes and embryonic fibroblasts to redox-driven apoptosis.

    Science.gov (United States)

    N'guessan, Prudence; Pouyet, Laurent; Gosset, Gaëlle; Hamlaoui, Sonia; Seillier, Marion; Cano, Carla E; Seux, Mylène; Stocker, Pierre; Culcasi, Marcel; Iovanna, Juan L; Dusetti, Nelson J; Pietri, Sylvia; Carrier, Alice

    2011-09-15

    The p53-transcriptional target TP53INP1 is a potent stress-response protein promoting p53 activity. We previously showed that ectopic overexpression of TP53INP1 facilitates cell cycle arrest as well as cell death. Here we report a study investigating cell death in mice deficient for TP53INP1. Surprisingly, we found enhanced stress-induced apoptosis in TP53INP1-deficient cells. This observation is underpinned in different cell types in vivo (thymocytes) and in vitro (thymocytes and MEFs), following different types of injury inducing either p53-dependent or -independent cell death. Nevertheless, absence of TP53INP1 is unable to overcome impaired cell death of p53-deficient thymocytes. Stress-induced ROS production is enhanced in the absence of TP53INP1, and antioxidant NAC complementation abolishes increased sensitivity to apoptosis of TP53INP1-deficient cells. Furthermore, antioxidant defenses are defective in TP53INP1-deficient mice in correlation with ROS dysregulation. Finally, we show that autophagy is reduced in TP53INP1-deficient cells both at the basal level and upon stress. Altogether, these data show that impaired ROS regulation in TP53INP1-deficient cells is responsible for their sensitivity to induced apoptosis. In addition, they suggest that this sensitivity could rely on a defect of autophagy. Therefore, these data emphasize the role of TP53INP1 in protection against cell injury.

  6. Voc Degradation in TF-VLS Grown InP Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yubo; Sun, Xingshu; Johnston, Steve; Sutter-Fella, Carolin M.; Hettick, Mark; Javey, Ali; Bermel, Peter

    2016-11-21

    Here we consider two hypotheses to explain the open-circuit voltage (VOC) degradation observed in thin-film vapor-liquid-solid (TF-VLS) grown p-type InP photovoltaic cells: bandgap narrowing and local shunting. First, a bandgap (Eg) narrowing effect is hypothesized, based on the surface inhomogeneity of VLS InP captured by the photoluminescence (PL) image. The PL data was used to estimate a spatially-resolved active VOC across surface of the InP sample. Combining this data with the effective Jsc allowed an assessment of the I-V characteristics of individual unit cells. Next, an H-SPICE diode compact model was utilized to reproduce the I-V characteristics of the whole sample. We find a good fit to the I-V performance of TF-VLS grown InP solar cell. Second, a local shunting effect was also considered as an alternative explanation of the VOC degradation effect. Again, PL image data was used, and small local shunt resistance was added in arbitrary elementary unit cells to represent certain dark spots seen in the PL image and dictate the VOC degradation occurred in the sample.

  7. The 3DVar Gridpoint Statistical Interpolation Impacts in the CPTEC/INPE Global Operational System

    Science.gov (United States)

    de Goncalves, L.

    2013-05-01

    A Global 3DVar (G3DVar) analysis cycle has become operacional since January 1st, 2013 at the Center for Weather Forecast and Climate Studies (CPTEC - Centro de Previsão de Tempo e Estudos Climáticos) from the Brazilian National Institute for Space Research (INPE - Instituto Nacional de Pesquisas Espaciais). The G3DVar, based upon the Gridpoint Statistical Interpolation (GSI) system produces every 6 hours analysis for the spectral T299L64 Atmospheric Global Circulation Model (AGCM/CPTEC/INPE) that runs at CPTEC/INPE to provide up to 168 hours forecasts. These analyses and forecasts were intercompared against the previous operational data assimilation scheme based on the Physical Space Assimilation System (PSAS) during two case studies for a typical South American summer meteorological system: the South Atlantic Convergence Zone (SACZ). This work presents the formal implementation of the G3DVar at CPTEC/INPE with a review of the satellite, conventional data and model background configurations along with the major improvements in the model skill when compared with the previous PSAS data assimilation system. Preliminary results show improvements in systematic errors for 850 and 250 hPa temperature, umididty and wind fields in the G3DVar compared to that in PSAS.

  8. Switching characteristics of an InP photonic crystal nanocavity: Experiment and theory

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel

    2013-01-01

    The dynamical properties of an InP photonic crystal nanocavity are experimentally investigated using pump-probe techniques and compared to simulations based on coupled-mode theory. Excellent agreement between experimental results and simulations is obtained when employing a rate equation model co...

  9. Surface chemistry of InP quantum dots: a comprehensive study.

    Science.gov (United States)

    Cros-Gagneux, Arnaud; Delpech, Fabien; Nayral, Céline; Cornejo, Alfonso; Coppel, Yannick; Chaudret, Bruno

    2010-12-29

    Advanced (1)H, (13)C, and (31)P solution and solid-state NMR studies combined with IR spectroscopy were used to probe, at the molecular scale, the composition and the surface chemistry of indium phosphide (InP) quantum dots (QDs) prepared via a non-coordinating solvent strategy. This nanomaterial can be described as a core-multishell object: an InP core, with a zinc blende bulk structure, is surrounded first by a partially oxidized surface shell, which is itself surrounded by an organic coating. This organic passivating layer is composed, in the first coordination sphere, of tightly bound palmitate ligands which display two different bonding modes. A second coordination sphere includes an unexpected dialkyl ketone and residual long-chain non-coordinating solvents (ODE and its isomers) which interact through weak intermolecular bonds with the alkyl chains of the carboxylate ligands. We show that this ketone is formed during the synthesis process via a decarboxylative coupling route and provides oxidative conditions which are responsible for the oxidation of the InP core surface. This phenomenon has a significant impact on the photoluminescence properties of the as-synthesized QDs and probably accounts for the failure of further growth of the InP core.

  10. Design procedure for millimeter-wave InP DHBT stacked power amplifiers

    DEFF Research Database (Denmark)

    Squartecchia, Michele; Johansen, Tom Keinicke; Midili, Virginio

    2015-01-01

    The stacked-transistor concept for power amplifiers (PA) has been investigated in this work. Specifically, this architecture has been applied in the design of millimeter-wave monolithic microwave integrated circuits (MMICs) using indium phosphide (InP) double heterojunction bipolar transistors...

  11. InP DHBT MMICs for millimeter-wave front-ends

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Hadziabdic, Dzenan; Krozer, Viktor

    2009-01-01

    In this paper, we show advanced MMIC's using InP DHBT technology. In particular, we demonstrate front-end circuits covering a broad frequency range from Q-band to E-band. Realizations of power amplifiers, quadrature VCOs, and sub-harmonic mixers, are presented and experimental results are discussed....

  12. Small- and large-signal modeling of InP HBTs in transferred-substrate technology

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Rudolph, Matthias; Jensen, Thomas

    2014-01-01

    In this paper, the small- and large-signal modeling of InP heterojunction bipolar transistors (HBTs) in transferred substrate (TS) technology is investigated. The small-signal equivalent circuit parameters for TS-HBTs in two-terminal and three-terminal configurations are determined by employing...

  13. X-Ray Photoelectron Spectroscopic Study of Oxidation of InP

    Science.gov (United States)

    Shibata, Noboru; Ikoma, Hideaki

    1992-12-01

    InP was oxidized chemically (in boiling deionized water), thermally (dry oxygen, 260°C, 30 min) and chemically under light illumination from a xenon arc lamp. The chemical compositions and their depth distributions from the surface of these oxides as well as the InP native oxide (naturally grown) were studied by angle-resolved X-ray photoelectron spectroscopy (XPS) and XPS combined with in situ Ar+ ion etching. In any oxide, indium is first oxidized to form In2O3 perhaps due to depletion of phosphorus from the InP surface induced by contact annealing, etc. InPO3 and/or InPO4 are then successively grown on an In2O3 or In2O3 rich layer. In and P atoms diffuse through the already grown In2O3 layer and react with oxidant at the surface to form InPO3 and/or InPO4. Light illumination was found to strongly enhance oxidation of InP, and substantially increase InPO3 and InPO4.

  14. An InP HBT sub-harmonic mixer for E-band wireless communication

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Krozer, Viktor

    2010-01-01

    This paper reports on a novel balanced HBT subharmonic mixer (SHM) for E-band wireless communication. An LO spiral type Marchand balun is integrated with the SHM. The SHM has been fabricated in a InP double heterojunction bipolar transistor (DHBT) circuit-oriented technology with fT /fmax = 180GHz...

  15. Investigation of High Speed ICs in InP Using MIS Structures.

    Science.gov (United States)

    1984-10-01

    3x3 digital multiplier for demonstration of the InP MISFET technolgy provides MSI levels of circuit integration as well as a self test mode of circuit...variables such as doping levels, oxide capacitance, mobility , transconductance, and even velocity saturation effects for short channel lengths. The end

  16. Fabrication and magnetic properties of granular Co/porous InP nanocomposite materials

    Directory of Open Access Journals (Sweden)

    Ma Li

    2011-01-01

    Full Text Available Abstract A novel Co/InP magnetic semiconductor nanocomposite was fabricated by electrodeposition magnetic Co nanoparticles into n-type porous InP templates in ethanol solution of cobalt chloride. The content or particle size of Co particles embedded in porous InP increased with increasing deposition time. Co particles had uniform distribution over pore sidewall surface of InP template, which was different from that of ceramic template and may open up new branch of fabrication of nanocomposites. The magnetism of such Co/InP nanocomposites can be gradually tuned from diamagnetism to ferromagnetism by increasing the deposition time of Co. Magnetic anisotropy of this Co/InP nanocomposite with magnetization easy axis along the axis of InP square channel was well realized by the competition between shape anisotropy and magnetocrystalline anisotropy. Such Co/InP nanocomposites with adjustable magnetism may have potential applications in future in the field of spin electronics. PACS: 61.46. +w · 72.80.Tm · 81.05.Rm · 75.75. +a · 82.45.Aa

  17. Reverse Current Characteristics of InP Gunn Diodes for W-Band Waveguide Applications.

    Science.gov (United States)

    Kim, Hyun-Seok; Heo, Jun-Woo; Chol, Seok-Gyu; Ko, Dong-Sik; Rhee, Jin-Koo

    2015-07-01

    InP is considered as the most promising material for millimeter-wave laser-diode applications owing to its superior noise performance and wide operating frequency range of 75-110 GHz. In this study, we demonstrate the fabrication of InP Gunn diodes with a current-limiting structure using rapid thermal annealing to modulate the potential height formed between an n-type InP active layer and a cathode contact. We also explore the reverse current characteristics of the InP Gunn diodes. Experimental results indicate a maximum anode current and an oscillation frequency of 200 mA and 93.53 GHz, respectively. The current-voltage characteristics are modeled by considering the Schottky and ohmic contacts, work function variations, negative differential resistance (NDR), and tunneling effect. Although no direct indication of the NDR is observed, the simulation results match the measured data well. The modeling results show that the NDR effect is always present but is masked because of electron emission across the shallow Schottky barrier.

  18. Millimeter‐wave INP DHBT power amplifier based on power‐optimized cascode configuration

    DEFF Research Database (Denmark)

    Johansen, Tom K.; Yan, Lei; Dupuy, Jean‐Yves

    2013-01-01

    This letter describes the use of a power‐optimized cascode configuration for obtaining maximum output power at millimeter‐wave (mm‐wave) frequencies for a two‐way combined power amplifier (PA). The PA has been fabricated in a high‐speed InP double heterojunction bipolar transistor technology...

  19. Design of mm-wave InP DHBT power amplifiers

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Yan, Lei

    2011-01-01

    power, gain, and efficiency. The design issues associated with cascode based power amplifiers at mm-wave frequencies is described. The experimental results on a two-way combined single-stage cascode based InP DHBT power amplifier demonstrate 13.4dB linear power gain and 12.5dBm saturated output power...

  20. Modeling of InP HBTs in Transferred-Substrate Technology for Millimeter-Wave Applications

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Rudolph, Matthias; Jensen, Thomas;

    2013-01-01

    In this paper, the modeling of InP heterojunction bipolar transistors (HBTs) in transferred substrate (TS) technology is investigated. At first, a direct parameter extraction methodology dedicated to III-V based HBTs is employed to determine the small-signal equivalent circuit parameters from...

  1. Saturation broadening effect in an InP photonic-crystal nanocavity switch

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel;

    2014-01-01

    Pump-probe measurements on InP photonic-crystal nanocavities show large-contrast fast switching at low pulse energy. For large pulse energies, large resonance shifts passing across the probe lead to switching contrast saturation and switching time-window broadening. © 2014 OSA....

  2. Potential of polarization lidar to provide profiles of CCN- and INP-relevant aerosol parameters

    Directory of Open Access Journals (Sweden)

    R. E. Mamouri

    2015-12-01

    Full Text Available We investigate the potential of polarization lidar to provide vertical profiles of aerosol parameters from which cloud condensation nucleus (CCN and ice nucleating particle (INP number concentrations can be estimated. We show that height profiles of number concentrations of aerosol particles with radius > 50 nm (APC50, reservoir of favorable CCN and with radius > 250 nm (APC250, reservoir of favorable INP, as well as profiles of the aerosol particle surface area concentration (ASC, used in INP parameterization can be retrieved from lidar-derived aerosol extinction coefficients (AEC with relative uncertainties of a factor of around 2 (APC50, and of about 25–50 % (APC250, ASC. Of key importance is the potential of polarization lidar to identify mineral dust particles and to distinguish and separate the aerosol properties of basic aerosol types such as mineral dust and continental pollution (haze, smoke. We investigate the relationship between AEC and APC50, APC250, and ASC for the main lidar wavelengths of 355, 532 and 1064 nm and main aerosol types (dust, pollution, marine. Our study is based on multiyear Aerosol Robotic Network (AERONET photometer observations of aerosol optical thickness and column-integrated particle size distribution at Leipzig, Germany, and Limassol, Cyprus, which cover all realistic aerosol mixtures of continental pollution, mineral dust, and marine aerosol. We further include AERONET data from field campaigns in Morocco, Cabo Verde, and Barbados, which provide pure dust and pure marine aerosol scenarios. By means of a simple relationship between APC50 and the CCN-reservoir particles (APCCCN and published INP parameterization schemes (with APC250 and ASC as input we finally compute APCCCN and INP concentration profiles. We apply the full methodology to a lidar observation of a heavy dust outbreak crossing Cyprus with dust up to 8 km height and to a case during which anthropogenic pollution dominated.

  3. Optical and structural properties of 100 MeV Fe{sup 9+} ion irradiated InP

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, R. L., E-mail: radhekrishna.dubey@xaviers.edu [Department of Physics, St. Xavier’s College-Autonomous, Mumbai-400 001 (India); Department of Physics, University of Mumbai, Mumbai-400 032 (India); Dubey, S. K. [Department of Physics, University of Mumbai, Mumbai-400 032 (India); Bodhane, S. P. [Department of Physics, St. Xavier’s College-Autonomous, Mumbai-400 001 (India); Kanjilal, D. [Inter University Accelerator Centre, ArunaAsaf Ali, Marg,New Delhi-110 067 (India)

    2016-05-06

    Single crystal InP samples were irradiated with 100 MeV Fe{sup 9+} ions for ion fluences 1x10{sup 12} and 1x10{sup 13} cm{sup −2}. Optical properties of irradiated InP was investigated by Spectroscopic Ellipsometry and UV-VIS-NIR spectroscopy. The optical parameters like, refractive index, extinction coefficient, absorption coefficient is found to be fluence dependent near the surface as well as near the projected range. Small change in the optical parameters near the surface region as investigated by Spectroscopic Ellipsometry indicatesthat the surfaces of irradiated InP are similar to non-irradiated InP. This is also supported by RBS/C measurements. The UV-VIS-NIR study revealed the decrease in the band gap and increase in the defect concentration in the irradiated sample as a result of nuclear energy loss.

  4. Voltammetric Study and Determination of Phenylephrine Hydrochloride at INP-Nafion-Modified CPE Sensor Employing Differential Pulse Voltammetry

    Directory of Open Access Journals (Sweden)

    Zeinab Pourghobadi

    2014-03-01

    Full Text Available In this study, describes the voltammetric oxidation and determination of phenylephrine (PHE hydrochloride at a new chemically modified electrode. Iron nanoparticle (INPs was dispersed in Nafion solution to obtain a INP-Nafion-modified CPE for the voltammetric analysis of PHE .The electrochemical behaviour of PHE on INP-Nafion-modified CPE was studied, using cyclic voltammetry as a diagnostic technique. The effects of amount of INPs-Nafion dispersion, pH, and scan rate on the response of modified electrode for the oxidation of PHE were investigated. Using differential pulse voltammetry (DPV, the modified electrode indicated a dynamic linear range for quantitative determination of PHE in the range of 5 μM−130 μM, and the detection limit was estimated to be 0.76 μM. The method was developed for the determination of PHE in pharmaceutical samples with satisfactory results.

  5. Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells

    Science.gov (United States)

    Walters, Robert J.; Statler, Richard L.; Summers, Geoffrey P.

    1991-01-01

    The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation.

  6. Potential of polarization lidar to provide profiles of CCN- and INP-relevant aerosol parameters

    Science.gov (United States)

    Mamouri, Rodanthi-Elisavet; Ansmann, Albert

    2016-05-01

    We investigate the potential of polarization lidar to provide vertical profiles of aerosol parameters from which cloud condensation nucleus (CCN) and ice nucleating particle (INP) number concentrations can be estimated. We show that height profiles of particle number concentrations n50, dry considering dry aerosol particles with radius > 50 nm (reservoir of CCN in the case of marine and continental non-desert aerosols), n100, dry (particles with dry radius > 100 nm, reservoir of desert dust CCN), and of n250, dry (particles with dry radius > 250 nm, reservoir of favorable INP), as well as profiles of the particle surface area concentration sdry (used in INP parameterizations) can be retrieved from lidar-derived aerosol extinction coefficients σ with relative uncertainties of a factor of 1.5-2 in the case of n50, dry and n100, dry and of about 25-50 % in the case of n250, dry and sdry. Of key importance is the potential of polarization lidar to distinguish and separate the optical properties of desert aerosols from non-desert aerosol such as continental and marine particles. We investigate the relationship between σ, measured at ambient atmospheric conditions, and n50, dry for marine and continental aerosols, n100, dry for desert dust particles, and n250, dry and sdry for three aerosol types (desert, non-desert continental, marine) and for the main lidar wavelengths of 355, 532, and 1064 nm. Our study is based on multiyear Aerosol Robotic Network (AERONET) photometer observations of aerosol optical thickness and column-integrated particle size distribution at Leipzig, Germany, and Limassol, Cyprus, which cover all realistic aerosol mixtures. We further include AERONET data from field campaigns in Morocco, Cabo Verde, and Barbados, which provide pure dust and pure marine aerosol scenarios. By means of a simple CCN parameterization (with n50, dry or n100, dry as input) and available INP parameterization schemes (with n250, dry and sdry as input) we finally compute

  7. On the usage of classical nucleation theory in quantification of the impact of bacterial INP on weather and climate

    Science.gov (United States)

    Sahyoun, Maher; Wex, Heike; Gosewinkel, Ulrich; Šantl-Temkiv, Tina; Nielsen, Niels W.; Finster, Kai; Sørensen, Jens H.; Stratmann, Frank; Korsholm, Ulrik S.

    2016-08-01

    Bacterial ice-nucleating particles (INP) are present in the atmosphere and efficient in heterogeneous ice-nucleation at temperatures up to -2 °C in mixed-phase clouds. However, due to their low emission rates, their climatic impact was considered insignificant in previous modeling studies. In view of uncertainties about the actual atmospheric emission rates and concentrations of bacterial INP, it is important to re-investigate the threshold fraction of cloud droplets containing bacterial INP for a pronounced effect on ice-nucleation, by using a suitable parameterization that describes the ice-nucleation process by bacterial INP properly. Therefore, we compared two heterogeneous ice-nucleation rate parameterizations, denoted CH08 and HOO10 herein, both of which are based on classical-nucleation-theory and measurements, and use similar equations, but different parameters, to an empirical parameterization, denoted HAR13 herein, which considers implicitly the number of bacterial INP. All parameterizations were used to calculate the ice-nucleation probability offline. HAR13 and HOO10 were implemented and tested in a one-dimensional version of a weather-forecast-model in two meteorological cases. Ice-nucleation-probabilities based on HAR13 and CH08 were similar, in spite of their different derivation, and were higher than those based on HOO10. This study shows the importance of the method of parameterization and of the input variable, number of bacterial INP, for accurately assessing their role in meteorological and climatic processes.

  8. Growth and characterization of InP ringlike quantum-dot molecules grown by solid-source molecular beam epitaxy.

    Science.gov (United States)

    Jevasuwan, Wipakorn; Boonpeng, Poonyasiri; Panyakeow, Somsak; Ratanathammaphan, Somchai

    2010-11-01

    In this paper, we have studied the fabrication of InP ringlike quantum-dot molecules on GaAs(001) substrate grown by solid-source molecular beam epitaxy using droplet epitaxy technique and the effect of In deposition rate on the physical and optical properties of InP ringlike quantum-dot molecules. The In deposition rate is varied from 0.2 ML/s to 0.4, 0.8 and 1.6 ML/s. The surface morphology and cross-section were examined by ex-situ atomic force microscope and transmission electron microscope, respectively. The increasing of In deposition rate results in the decreasing of outer and inner diameters of InP ringlike quantum-dot molecules and height of InP quantum dots but increases the InP quantum dot and ringlike quantum-dot molecule densities. The photoluminescence peaks of InP ringlike quantum-dot molecules are blue-shifted and FWHM is narrower when In deposition rate is bigger.

  9. Electrostatic Stabilized InP Colloidal Quantum Dots with High Photoluminescence Efficiency.

    Science.gov (United States)

    Mnoyan, Anush N; Kirakosyan, Artavazd Gh; Kim, Hyunki; Jang, Ho Seong; Jeon, Duk Young

    2015-06-30

    Electrostatically stabilized InP quantum dots (QDs) showing a high luminescence yield of 16% without any long alkyl chain coordinating ligands on their surface are demonstrated. This is achieved by UV-etching the QDs in the presence of fluoric and sulfuric acids. Fluoric acid plays a critical role in selectively etching nonradiative sites during the ligand-exchange process and in relieving the acidity of the solution to prevent destruction of the QDs. Given that the InP QDs show high luminescence without any electrical barriers, such as long alkyl ligands or inorganic shells, this method can be applied for QD treatment for application to highly efficient QD-based optoelectronic devices.

  10. Influence of growth conditions on the performance of InP nanowire solar cells

    Science.gov (United States)

    Cavalli, Alessandro; Cui, Yingchao; Kölling, Sebastian; Verheijen, Marcel A.; Plissard, Sebastien R.; Wang, Jia; Koenraad, Paul M.; Haverkort, Jos E. M.; Bakkers, Erik P. A. M.

    2016-11-01

    Nanowire based solar cells have attracted great attention due to their potential for high efficiency and low device cost. Photovoltaic devices based on InP nanowires now have characteristics comparable to InP bulk solar cells. A detailed and direct correlation of the influence of growth conditions on performance is necessary to improve efficiency further. We explored the effects of the growth temperature, and of the addition of HCl during growth, on the efficiency of nanowire array based solar cell devices. By increasing HCl, the saturation dark current was reduced, and thereby the nanowire solar cell efficiency was enhanced from less than 1% to 7.6% under AM 1.5 illumination at 1 sun. At the same time, we observed that the solar cell efficiency decreased by increasing the tri-methyl-indium content, strongly suggesting that these effects are carbon related.

  11. Low-Threshold Conjugated Polymer Distributed Feedback Lasers on InP Substrate

    Institute of Scientific and Technical Information of China (English)

    ZHANG Su-Mei; ZHANG Ding-Ke; MA Dong-Ge

    2008-01-01

    We demonstrate a low threshold polymer sofid state thin-film distributed feedback (DFB) laser on an InP substrate with the DFB structure.The used gain medium is conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene](MEH-PPV) doped polystyrene (PS) and formed by drop-coating method.The second order Bragg scattering region on the InP substrate gave rise to strong feedback,thus a lazing emission at 638.9nm with a line width of 1.2nm is realized when pumped by a 532nm frequency-doubled Nd:YAG pulsed laser.The devices show a laser threshold as low as 7n J/pulse.

  12. Far field emission profile of pure wurtzite InP nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Bulgarini, Gabriele, E-mail: g.bulgarini@tudelft.nl; Reimer, Michael E.; Zwiller, Val [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Dalacu, Dan; Poole, Philip J.; Lapointe, Jean [National Research Council, Ottawa, Ontario, K1A 0R6 (Canada)

    2014-11-10

    We report on the far field emission profile of pure wurtzite InP nanowires in comparison to InP nanowires with predominantly zincblende crystal structure. The emission profile is measured on individual nanowires using Fourier microscopy. The most intense photoluminescence of wurtzite nanowires is collected at small angles with respect to the nanowire growth axis. In contrast, zincblende nanowires present a minimum of the collected light intensity in the direction of the nanowire growth. Results are explained by the orientation of electric dipoles responsible for the photoluminescence, which is different from wurtzite to zincblende. Wurtzite nanowires have dipoles oriented perpendicular to the nanowire growth direction, whereas zincblende nanowires have dipoles oriented along the nanowire axis. This interpretation is confirmed by both numerical simulations and polarization dependent photoluminescence spectroscopy. Knowledge of the dipole orientation in nanostructures is crucial for developing a wide range of photonic devices such as light-emitting diodes, photodetectors, and solar cells.

  13. Influence of growth conditions on the performance of InP nanowire solar cells.

    Science.gov (United States)

    Cavalli, Alessandro; Cui, Yingchao; Kölling, Sebastian; Verheijen, Marcel A; Plissard, Sebastien R; Wang, Jia; Koenraad, Paul M; Haverkort, Jos E M; Bakkers, Erik P A M

    2016-11-11

    Nanowire based solar cells have attracted great attention due to their potential for high efficiency and low device cost. Photovoltaic devices based on InP nanowires now have characteristics comparable to InP bulk solar cells. A detailed and direct correlation of the influence of growth conditions on performance is necessary to improve efficiency further. We explored the effects of the growth temperature, and of the addition of HCl during growth, on the efficiency of nanowire array based solar cell devices. By increasing HCl, the saturation dark current was reduced, and thereby the nanowire solar cell efficiency was enhanced from less than 1% to 7.6% under AM 1.5 illumination at 1 sun. At the same time, we observed that the solar cell efficiency decreased by increasing the tri-methyl-indium content, strongly suggesting that these effects are carbon related.

  14. Monte Carlo investigation of avalanche multiplication process in thin InP avalanche photodiodes

    Institute of Scientific and Technical Information of China (English)

    WANG Gang; MA YuXiang

    2009-01-01

    An ensemble Monte Carlo simulation is presented to investigate the avalanche multiplication process in thin InP avalanche photodiodes (APDs). Analytical band structures are applied to the description of the conduction and valence band, and impact ionization is treated as an additional scattering mecha-nism with the Keldysh formula. Multiplication gain and excess noise factor of InP p~+-i-n~+ APDs aresimulated and obvious excess noise reduction is found in the thinner devices. The effect of dead space on excess noise in thin APD structures is investigated by the distribution of impact ionization events within the multiplication region. It is found that the dead space can suppress the feedback ionization events resulting in a more deterministic avalanche multiplication process and reduce the excess noise in thinner APDs.

  15. InP solid state detector for measurement of low energy solar neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Yoshiyuki, E-mail: fukuda@staff.miyakyo-u.ac.j [Faculty of Education, Miyagi University of Education, 149, Aobaku-aza-aoba, Sendai, Miyagi 980-0845 (Japan); Izawa, Toshiyuki [Solid State Division, Hamamatsu Photonics K.K. 1126-1, Ichino-cho, Hamamatsu, Shizuoka 435-8558 (Japan); Koshio, Yusuke; Moriyama, Shigetaka [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Higashi-Mozumi, Kamioka-cho, Hida, Gifu 506-1205 (Japan); Namba, Toshio [ICEPP, International Center for Elementary Particle Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Shiozawa, Masato [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Higashi-Mozumi, Kamioka-cho, Hida, Gifu 506-1205 (Japan)

    2010-11-01

    A large volume radiation detector using a semi-insulating Indium Phosphide (InP) wafer has been developed for Indium Project on Neutrino Observation for Solar interior (IPNOS) experiment. We have achieved the volume of 20 mm{sup 3}, and this is world largest one among InP detectors which observed {gamma}'s at hundred keV region. In spite of the depletion layer, most of charge generated by electron hole pair production are collected by an induction, and the charge collection efficiency and the energy resolution are obtained by 60% and 25%, respectively. We measured actual backgrounds related to {sup 115}In {beta} decay, and no significant background was found.

  16. Surface characterization of InP trenches embedded in oxide using scanning probe microscopy

    Science.gov (United States)

    Mannarino, Manuel; Chintala, Ravi; Moussa, Alain; Merckling, Clement; Eyben, Pierre; Paredis, Kristof; Vandervorst, Wilfried

    2015-12-01

    Metrology for structural and electrical analyses at device level has been identified as one of the major challenges to be resolved for the sub-14 nm technology nodes. In these advanced nodes, new high mobility semiconductors, such as III-V compounds, are grown in narrow trenches on a Si substrate. Probing the nature of the defects, the defect density, and the role of processing steps on the surface of such structures are prime metrology requirements. In order to enable defect analysis on a (III-V) surface, a proper sample preparation for oxide removal is of primary importance. In this work, the effectiveness of different chemical cleanings and thermal annealing procedures is investigated on both blanket InP and oxide embedded InP trenches by means of scanning probe microscopy techniques. It is found that the most effective approach is a combination of an HCl-based chemical cleaning combined with a low-temperature thermal annealing leading to an oxide free surface with atomically flat areas. Scanning tunneling microscopy (STM) has been the preferred method for such investigations on blanket films due to its intrinsic sub-nm spatial resolution. However, its application on oxide embedded structures is non-trivial. To perform STM on the trenches of interest (generally <20 nm wide), we propose a combination of non-contact atomic force microscopy and STM using the same conductive atomic force microscopy tip Our results prove that with these procedures, it is possible to perform STM in narrow InP trenches showing stacking faults and surface reconstruction. Significant differences in terms of roughness and terrace formation are also observed between the blanket and the oxide embedded InP.

  17. Electrical and thermal characterization of single and multi-finger InP DHBTs

    DEFF Research Database (Denmark)

    Midili, Virginio; Nodjiadjim, V.; Johansen, Tom Keinicke

    2015-01-01

    This paper presents the characterization of single and multi-finger Indium Phosphide Double Heterojunction Bipolar transistors (InP DHBTs). It is used as the starting point for technology optimization. Safe Operating Area (SOA) and small signal AC parameters are investigated along with thermal...... characteristics. The results are presented comparing different device dimensions and number of fingers. This work gives directions towards further optimization of geometrical parameters and reduction of thermal effects....

  18. Bandgap Engineering of InP QDs Through Shell Thickness and Composition

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, Allison M. [Los Alamos National Laboratory; Mangum, Benjamin D. [Los Alamos National Laboratory; Piryatinski, Andrei [Los Alamos National Laboratory; Park, Young-Shin [Los Alamos National Laboratory; Htoon, Han [Los Alamos National Laboratory; Hollingsworth, Jennifer A. [Los Alamos National Laboratory

    2012-06-21

    Fields as diverse as biological imaging and telecommunications utilize the unique photophysical and electronic properties of nanocrystal quantum dots (NQDs). The development of new NQD compositions promises material properties optimized for specific applications, while addressing material toxicity. Indium phosphide (InP) offers a 'green' alternative to the traditional cadmium-based NQDs, but suffers from extreme susceptibility to oxidation. Coating InP cores with more stable shell materials significantly improves nanocrystal resistance to oxidation and photostability. We have investigated several new InP-based core-shell compositions, correlating our results with theoretical predictions of their optical and electronic properties. Specifically, we can tailor the InP core-shell QDs to a type-I, quasi-type-II, or type-II bandgap structure with emission wavelengths ranging from 500-1300 nm depending on the shell material used (ZnS, ZnSe, CdS, or CdSe) and the thickness of the shell. Single molecule microscopy assessments of photobleaching and blinking are used to correlate NQD properties with shell thickness.

  19. Enhanced luminescence of near-surface quantum wells passivated in situ by InP

    Energy Technology Data Exchange (ETDEWEB)

    Lipsanen, H.; Sopanen, M.; Taskinen, M.; Tulkki, J. [Helsinki Univ. of Technology, Espoo (Finland). Optoelectronics Lab.; Ahopelto, J. [VTT Electronics, Espoo (Finland)

    1996-12-31

    The authors have studied the optical properties of MOVPE grown Al{sub x}Ga{sub 1{minus}x}As/GaAs structures passivated by in situ deposition of InP on the surface. One monolayer of InP was used for the passivation. The surface recombination was studied by photoluminescence measurements of near-surface Al{sub 0.22}Ga{sub 0.78}As/GaAs quantum wells. The luminescence intensity of the passivated samples increased by about five orders of magnitude for quantum wells located at less than 5 nm from the surface as compared to unpassivated samples. Furthermore, the authors observed a blueshift of 15 meV for a passivated surface quantum well. The effect of the thin InP layer on the Fermi level pinning on the surface was studied by photoreflectance of a surface-i-n{sup +} sample. The pinning position was reduced by 0.3 eV from the mid-bandgap value.

  20. High performance photodetectors based on high quality InP nanowires

    Science.gov (United States)

    Yang, Yan-Kun; Yang, Tie-Feng; Li, Hong-Lai; Qi, Zhao-Yang; Chen, Xin-Liang; Wu, Wen-Qiang; Hu, Xue-Lu; He, Peng-Bin; Jiang, Ying; Hu, Wei; Zhang, Qing-Lin; Zhuang, Xiu-Juan; Zhu, Xiao-Li; Pan, An-Lian

    2016-11-01

    In this paper, small diameter InP nanowires with high crystal quality were synthesized through a chemical vapor deposition method. Benefitting from the high crystallinity and large specific surface area of InP nanowires, the simply constructed photodetector demonstrates a high responsivity of up to 1170 A·W-1 and an external quantum efficiency of 2.8×105% with a fast rise time of 110 ms and a fall time of 130 ms, even at low bias of 0.1 V. The effect of back-gate voltage on photoresponse of the device was systematically investigated, confirming that the photocurrent dominates over thermionic and tunneling currents in the whole operation. A mechanism based on energy band theory at the junction between metal and semiconductor was proposed to explain the back-gate voltage dependent performance of the photodetectors. These convincing results indicate that fine InP nanowires will have a brilliant future in smart optoelectronics. Project supported by the National Natural Science Foundation of China (Grant Nos. 51525202, 61574054, 61505051, and 61474040), the Science and Technology Plan of Hunan Province, China (Grant Nos. 2014FJ2001 and 2014TT1004), and the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China.

  1. Optical reflectance studies of highly specular anisotropic nanoporous (111) InP membrane

    Science.gov (United States)

    Steele, J. A.; Lewis, R. A.; Sirbu, L.; Enachi, M.; Tiginyanu, I. M.; Skuratov, V. A.

    2015-04-01

    High-precision optical angular reflectance measurements are reported for a specular anisotropic nanoporous (111) InP membrane prepared by doping-assisted wet-electrochemical etching. The membrane surface morphology was investigated using scanning electron microscope imaging and revealed a quasi-uniform and self-organized nanoporous network consisting of semiconductor ‘islands’ in the sub-wavelength regime. The optical response of the nanoporous InP surface was studied at 405 nm (740 THz; UV), 633 nm (474 THz; VIS) and 1064 nm (282 THz; NIR), and exhibited a retention of basic macro-dielectric properties. Refractive index determinations demonstrate an optical anisotropy for the membrane which is strongly dependent on the wavelength of incident light, and exhibits an interesting inversion (positive anisotropy to negative) between 405 and 633 nm. The inversion of optical anisotropy is attributed to a strongly reduced ‘metallic’ behaviour in the membrane when subject to above-bandgap illumination. For the simplest case of sub-bandgap incident irradiation, the optical properties of the nanoporous InP sample are analysed in terms of an effective refractive index neff and compared to effective media approximations.

  2. Weakly doped InP layers prepared by liquid phase epitaxy using a modulated cooling rate

    Science.gov (United States)

    Krukovskyi, R.; Mykhashchuk, Y.; Kost, Y.; Krukovskyi, S.; Saldan, I.

    2017-04-01

    Epitaxial structures based on InP are widely used to manufacture a number of devices such as microwave transistors, light-emitting diodes, lasers and Gunn diodes. However, their temporary instability caused by heterogeneity of resistivity along the layer thickness and the influence of various external or internal factors prompts the need for the development of a new reliable technology for their preparation. Weak doping by Yb, Al and Sn together with modulation of the cooling rate applied to prepare InP epitaxial layers is suggested to be adopted within the liquid phase epitaxy (LPE) method. The experimental results confirm the optimized conditions created to get a uniform electron concentration in the active n-InP layer. A sharp profile of electron concentration in the n+-InP(substrate)/n-InP/n+-InP epitaxial structure was observed experimentally at the proposed modulated cooling rate of 0.3 °С-1.5 °С min-1. The proposed technological method can be used to control the electrical and physical properties of InP epitaxial layers to be used in Gunn diodes.

  3. Aqueous bromine etching of InP: a specific surface chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Causier, A.; Bouttemy, M.; Gerard, I.; Aureau, D.; Vigneron, J.; Etcheberry, A. [Institut Lavoisier de Versailles, Versailles-Saint-Quentin University, UMR CNRS 8180, 45 Av. des Etats-Unis, 78035 Versailles (France)

    2012-06-15

    The n -InP behaviour in HBr (0.1-1.0 M)/Br{sub 2} (1.25 x 10{sup -2}M) aqueous solutions is studied by AAS, XPS and SEM-FEG. Indium AAS-titrations of the HBr/Br{sub 2} solutions demonstrate that InP undergoes an etching mechanism whatever the HBr/Br{sub 2} formulation. The etching process is always linear with time but its rate depends on the HBr concentration. XPS analyses permit to link the apparent slow-down of the dissolution process when decreasing the HBr molarity from 1.0 M to 0.1 M to the presence of a mixed (In,P){sub ox} oxide layer on the surface. Therefore, the dissolution process of InP in HBr/Br{sub 2} solution appears to be ruled by the surface chemical state (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Thin films of InP for photovoltaic energy conversion. Final report, July 5, 1979-July 4, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Manasevit, H. M.; Ruth, R. P.; Moudy, L. A.; Yang, J. J.J.; Johnson, R. E.

    1980-08-01

    Research to develop a low-cost high-efficiency thin-film InP heterojunction solar cell, using the metalorganic chemical vapor deposition (MO-CVD) technique for InP film growth on suitable substrates is reported. Heterostructure devices of CdS/InP, using InP films prepared by CO-CVD, were prepared and characterized. The research effort involved three major technical tasks: (1) materials growth; (2) materials characterization; and (3) device fabrication and characterization. The principal results achieved in the investigations are as follows: (1) temperature-activated orientation-dependent background donor doping was observed in undoped epitaxial InP films; (2) p-type epitaxial InP films were prepared by Zn and by Cd doping during growth; (3) the efficacy of Cd doping was found to vary exponentially with the reciprocal of the deposition temperature in the range 650 to 730/sup 0/C; (4) Cd doping appeared to offer no clear advantages over Zn doping for preparation of p-type InP by the MO-CVD process; (5) GaP grown by MO-CVD was investigated as a possible intermediate-layer material for growth of InP films on low-cost substrates; (6) p/sup +/GaAs polycrystalline layers (p > /sup 19/ cm/sup -3/) were successfully prepared by Zn doping during MO-CVD growth on various low-cost substrates and used as surfaces for growth of p-type polycrystalline InP:Zn layers; (7) nCdS/pInP heterojunction solar cells were prepared by vacuum deposition of CdS onto p-type InP films grown by MO-CVD as well as on InP single-crystal wafers; (8) the best polycrystalline CdS/InP cells were obtained in structures on P/sup +/GaAs:Zn layers on both Mo sheet and Corning Code 0317 Glass; and (9) structure analyses of the Cds films used in the heterojunction cells indicated the presence of polycrystalline hexagonal CdS even in films grown on single-crystal InP films or bulk-wafer substrates. (WHK)

  5. Pembuatan Biodiesel Dari Minyak Kelapa Sawit RBD Dengan Menggunakan Katalis Berpromotor Ganda Berpenyangga γ-Alumina (CaO/MgO/ γ-Al2O3 Dalam Reaktor Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Niar Kurnia Julianti

    2014-09-01

    Full Text Available Biodiesel merupakan salah satu energi alternatif pengganti bahan bakar fosil dari hasil reaksi transesterifikasi minyak nabati dengan metanol. Proses pembuatan biodiesel selama ini menggunakan katalis homogen NaOH atau KOH yang memiliki kelemahan terbentuknya produk samping berupa sabun dan rumitnya pemisahan produk biodiesel dengan katalis. Maka dari itu, mulai dikembangkan katalis heterogen. Penelitian ini mengembangkan katalis berpromotor ganda berpenyangga y-alumina (CaO/MgO/y-Al2O3 dalam reaktor fluidized bed. Pembuatan katalis melalui metode presipitasi CaO dan MgO pada y-Al2O3 serta asam asetat sebagai larutan precursor. Kemudian, katalis dioven selama 12 jam pada suhu 110C dan dikalsinasi pada suhu 700 C selama 5 jam. Katalis yang diperoleh digunakan untuk proses transesterifikasi dengan ratio molar minyak metanol 1:36; variabel massa katalis 4, 7, 10, 13, 16 gram; laju alir reaktan 4, 7, 10, 13, 16 ml/menit; dan suhu 125, 150, 175, 200, 225 C. Dimana yield dan % konversi terbaik dari penelitian diperoleh sebesar 0,642 gr biodiesel/gr minyak dan 63,975% pada massa katalis 16 gram, suhu 225 C dan laju alir reaktan 4 ml/menit.

  6. Defects in mitophagy promote redox-driven metabolic syndrome in the absence of TP53INP1.

    Science.gov (United States)

    Seillier, Marion; Pouyet, Laurent; N'Guessan, Prudence; Nollet, Marie; Capo, Florence; Guillaumond, Fabienne; Peyta, Laure; Dumas, Jean-François; Varrault, Annie; Bertrand, Gyslaine; Bonnafous, Stéphanie; Tran, Albert; Meur, Gargi; Marchetti, Piero; Ravier, Magalie A; Dalle, Stéphane; Gual, Philippe; Muller, Dany; Rutter, Guy A; Servais, Stéphane; Iovanna, Juan L; Carrier, Alice

    2015-03-30

    The metabolic syndrome covers metabolic abnormalities including obesity and type 2 diabetes (T2D). T2D is characterized by insulin resistance resulting from both environmental and genetic factors. A genome-wide association study (GWAS) published in 2010 identified TP53INP1 as a new T2D susceptibility locus, but a pathological mechanism was not identified. In this work, we show that mice lacking TP53INP1 are prone to redox-driven obesity and insulin resistance. Furthermore, we demonstrate that the reactive oxygen species increase in TP53INP1-deficient cells results from accumulation of defective mitochondria associated with impaired PINK/PARKIN mitophagy. This chronic oxidative stress also favors accumulation of lipid droplets. Taken together, our data provide evidence that the GWAS-identified TP53INP1 gene prevents metabolic syndrome, through a mechanism involving prevention of oxidative stress by mitochondrial homeostasis regulation. In conclusion, this study highlights TP53INP1 as a molecular regulator of redox-driven metabolic syndrome and provides a new preclinical mouse model for metabolic syndrome clinical research.

  7. Studies on semiconductors based on InP with sub-ps response times; Untersuchungen an auf InP basierenden Halbleitern mit sub-ps Responsezeiten

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, K.

    2007-06-28

    The present work describes investigation of new material concepts accomplished using molecular-beam-epitaxy (MBE) growth for application in ultra-fast photonic components. Nominally undoped and Be doped GaInAs/AlInAs multiple-quantumwell structures (MQW) were grown by MBE at growth temperatures down to 100 C (LT-MBE) on semi-insulating InP substrates. Crystalline, electric and optical properties of as-grown and annealed structures were investigated. Energy states near the conduction band of GaInAs determine the electrical and optical properties of LT-MQWs. The dynamics of charge carrier relaxation was studied by means of pump and probe experiments. Measurements of the differential transmission when excited by an additional cw laser and measurements utilizing two closely sequenced pump pulses support the capability of Be doped as-grown (annealed) LT GaInAs/AlInAs MQW structures for use in optical switches at switching frequencies in the 1 Tbit/s (250 Gbit/s) range. The voltage-induced change of interband transmission of InP based quantumcascade-lasers (QCL) during pulsed mode operation was analyzed by means of 8 band k.p calculations. The impacts of varying charge carrier distributions and of electrically heated samples can be neglected compared to the dominating effect of the electrical field on the interband transmission. The impact of MBE growth parameters on the interface quality of AlAsSb/ GaInAs heterostructures were determined by means of Hall measurements, temperature- and intensity-dependent PL measurements and spectral measurements of the interband- and intersubband-absorption. The impact of In segregation and Sb diffusion on the intersubband absorption was analyzed on the basis of bandstructure calculations. Intersubband transitions at wavelengths of about 1.8 {mu}m (1.55 {mu}m) were successfully achieved in MQW (coupled QW) structures. (orig.)

  8. InP by Planar Reactive Deposition and GaAs by Low Pressure Metal Organic Chemical Vapor Deposition.

    Science.gov (United States)

    1981-02-01

    This inter- pretation is consistent with the fact that In2S3 is quite stable,(L7,18) whereas Cd2P 3 is quite volatile. (19) InP did not form until the...hypothesis regarding InP grain boundary passivation. Besides InP and CdS, the compounds Cd 2P3 , CdIn 2 S4 (Ref. 20) and (CdS)3x - ( In2S3 ).x (Ref. 18...PROCESSING: 2HRSAT425 C CdS +,(BARS) 1 GLASS SIDE VIEW I n (S)~,I (DOTS)~ (BARS) In2S3 (DOTS) (Cd) Figure 6. Scanning electron microscope (left) and

  9. Synthesis and properties of ultra-long InP nanowires on glass

    Science.gov (United States)

    Dhaka, Veer; Pale, Ville; Khayrudinov, Vladislav; Kakko, Joona-Pekko; Haggren, Tuomas; Jiang, Hua; Kauppinen, Esko; Lipsanen, Harri

    2016-12-01

    We report on the synthesis of Au-catalyzed InP nanowires (NWs) on low-cost glass substrates. Ultra-dense and ultra-long (up to ˜250 μm) InP NWs, with an exceptionally high growth rate of ˜25 μm min-1, were grown directly on glass using metal organic vapor phase epitaxy (MOVPE). Structural properties of InP NWs grown on glass were similar to the ones grown typically on Si substrates showing many structural twin faults but the NWs on glass always exhibited a stronger photoluminescence (PL) intensity at room temperature. The PL measurements of NWs grown on glass reveal two additional prominent impurity related emission peaks at low temperature (10 K). In particular, the strongest unusual emission peak with an activation energy of 23.8 ± 2 meV was observed at 928 nm. Different possibilities including the role of native defects (phosphorus and/or indium vacancies) are discussed but most likely the origin of this PL peak is related to the impurity incorporation from the glass substrate. Furthermore, despite the presence of suspected impurities, the NWs on glass show outstanding light absorption in a wide spectral range (60%-95% for λ = 300-1600 nm). The optical properties and the NW growth mechanism on glass is discussed qualitatively. We attribute the exceptionally high growth rate mostly to the atmospheric pressure growth conditions of our MOVPE reactor and stronger PL intensity on glass due to the impurity doping. Overall, the III-V NWs grown on glass are similar to the ones grown on semiconductor substrates but offer additional advantages such as low-cost and light transparency.

  10. Tunnel diode collector contact in InP based PNP heterojunction bipolar transistors

    Science.gov (United States)

    Shamir, N.; Ritter, D.; Cytermann, C.

    2002-06-01

    A tunnel diode collector contact to InP based PNP heterojunction bipolar transistors (HBTs) is suggested and demonstrated. The additional heavily doped n-type contact layer replaces the thick p-type contact layer required in conventional structures. The thermal and electrical properties of the collector contact layer thus become similar to those of NPN HBTs. A secondary ion mass spectroscopy study explores the maximum tin doping level that can be obtained in the base. Finally, the temperature dependence of the current gain is presented and interpreted.

  11. Confinement effect in a quantum well dot induced by an InP stressor

    Science.gov (United States)

    Tulkki, J.; Heinämäki, A.

    1995-09-01

    We have calculated the confinement effect in an In1-xGaxAs/GaAs quantum well dot induced by a dislocation-free InP stressor island. The energy levels were calculated by including the strain interaction and the band-edge confinement in the Luttinger-Kohn Hamiltonian. The maximum level spacing for the dipole-allowed interband E1-->HH1 line spectrum was 20 meV. Our calculation also gives excellent agreement with recent measurements [H. Lipsanen, M. Sopanen, and J. Ahopelto, Phys. Rev. B 51, 13 868 (1995)] and provides indirect evidence of screened Coulomb interaction, tentatively addressed to slow carrier relaxation.

  12. Implantación iónica en InP para aplicaciones en dispositivos

    OpenAIRE

    Martín Pacheco, Jaime Miguel

    1995-01-01

    La presente tesis muestra en primer lugar los sistemas de control diseñados y desarrollados para conseguir el perfecto funcionamiento del implantador de la facultad de físicas. Se presenta luego un completo estudio de la obtención por implantación de capas tipo n (por implantaciones de si y si/p), tipo p (con mg, mg/p o mg/ar) y capas de alta resistividad (por he y ti) en inp, tanto desde el punto de vista eléctrico (medidas de resistividad y efecto hall y de sims) como óptico (por fotolumini...

  13. Surface organization of homoepitaxial InP films grown by metalorganic vapor-phase epitaxy

    OpenAIRE

    Gocalinska, A.; Manganaro, M.; Vvedensky, D. D.; Pelucchi, E.

    2012-01-01

    We present a systematic study of the morphology of homoepitaxial InP films grown by metalorganic vapor-phase epitaxy which are imaged with ex situ atomic force microscopy. These films show a dramatic range of different surface morphologies as a function of the growth conditions and substrate (growth temperature, V/III ratio, and miscut angle < 0.6deg and orientation toward A or B sites), ranging from stable step flow to previously unreported strong step bunching, over 10 nm in height. These o...

  14. Growth temperature dependence of exciton lifetime in wurtzite InP nanowires grown on silicon substrates

    Science.gov (United States)

    Chauvin, N.; Hadj Alouane, M. H.; Anufriev, R.; Khmissi, H.; Naji, K.; Patriarche, G.; Bru-Chevallier, C.; Gendry, M.

    2012-01-01

    InP nanowires grown on silicon substrate are investigated using time-resolved spectroscopy. A strong modification of the exciton lifetime is observed (from 0.11 to 1.2 ns) when the growth temperature is increased from 340 °C to 460 °C. This strong dependence is not related to the density of zinc-blende insertions in the wurtzite nanowires or to the wurtzite exciton linewidth. The excitation power dependence of the lifetime and linewidth is investigated, and these results allow us to interpret the growth temperature dependence on the lifetime as a consequence of the reduction of the surface recombination velocity with the growth temperature.

  15. Optical anisotropy in InP string-like aligned quantum dots

    Science.gov (United States)

    Kim, Yongmin; Song, J. D.; Han, I. K.

    2014-06-01

    InP quantum dots were grown by using the molecular beam epitaxy technique. The quantum dots were connected and composed a string-like one-dimensional structure in the [1-10] crystal direction due to the strain field along the [110] direction. Two prominent photoluminescence transitions from normal quantum dots and string-like one-dimensional structures were observed and showed strong optical emission anisotropy. Both peaks also showed blue-shifts while rotating the emission polarization from the [1-10] to the [110] direction. Such optical transition behaviors are the consequence of valence band mixing caused by the strain field along the [110] crystal direction.

  16. Langmuir-Blodgett monolayers of InP quantum dots with short chain ligands.

    Science.gov (United States)

    Lambert, K; Wittebrood, L; Moreels, I; Deresmes, D; Grandidier, B; Hens, Z

    2006-08-15

    We demonstrate the organization of nearly monodisperse colloidal InP quantum dots at the air/water interface in Langmuir monolayers. The organization of the particles is monitored in situ by surface pressure-surface area measurements and ex situ by AFM measurements on films transferred to mica by Langmuir-Blodgett deposition. The influence of different ligands on the quality of the monolayer formed has been studied. We show that densely packed monolayers with little holes can be formed using short chain ligands like pyridine and pentamethylene sulfide. The advantage of using short chain ligands for electron tunneling to or from the quantum dots is demonstrated using scanning tunneling spectroscopy.

  17. Influence of Grain Size on Electrical and Optical Properties of InP Films

    Institute of Scientific and Technical Information of China (English)

    Mustafa (O)ztas

    2008-01-01

    InP film samples were prepared by spray pyrolysis technique using aqueous solutions of lnCl3 and Na2HPO4,which were atomized with compressed air as carrier gas onto glass substrates at 500℃ with different thicknesses of the films. It is found that the resistivity of the polycrystalline films strongly depends on the grain size. It is observed that the grain size of the films increase with the decrease of the energy band gap and strain of the film.The changes observed in the energy band gap and strain related to the film grain size of the films are discussed in detail.

  18. Hydrogen passivation of N(+)-P and P(+)-N heteroepitaxial InP solar cell structures

    Science.gov (United States)

    Chatterjee, Basab; Davis, William C.; Ringel, Steve A.; Hoffman, Richard, Jr.

    1996-01-01

    Dislocations and related point defect complexes caused by lattice mismatch currently limit the performance of heteroepitaxial InP cells by introducing shunting paths across the active junction and by the formation of deep traps within the base region. We have previously demonstrated that plasma hydrogenation is an effective and stable means to passivate the electrical activity of such defects in specially designed heteroepitaxial InP test structures to probe hydrogen passivation at typical base depths within a cell structure. In this work, we present our results on the hydrogen passivation of actual heteroepitaxial n-p and p-n InP cell structures grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD). We have found that a 2 hour exposure to a 13.56 MHz hydrogen plasma at 275 C reduces the deep level concentration in the base regions of both n(+)-p and p(+)-n heteroepitaxial InP cell structures from as-grown values of 5-7 x 10(exp 14) cm(exp -3), down to 3-5 x 10(exp 12) cm(exp -3). All dopants were successfully reactivated by a 400 C, 5 minute anneal with no detectable activation of deep levels. One to five analysis indicated a subsequent approximately 100 fold decrease in reverse leakage current at -1 volt reverse bias, and an improved built in voltage for the p(+)-n structures. In addition to being passivated, dislocations are also shown to participate in secondary interactions during hydrogenation. We find that the presence of dislocations enhances hydrogen diffusion into the cell structure, and lowers the apparent dissociation energy of Zn-H complexes from 1.19 eV for homoepitaxial Zn-doped InP to 1.12 eV for heteroepitaxial Zn-doped InP. This is explained by additional hydrogen trapping at dislocations subsequent to the reactivation of Zn dopants after hydrogenation.

  19. Hydrogen Passivation of N(+)P and P(+)N Heteroepitaxial InP Solar Cell Structures

    Science.gov (United States)

    Chatterjee, B.; Davis, W. C.; Ringel, S. A.; Hoffman, R., Jr.

    1995-01-01

    Dislocations and related point defect complexes caused by lattice mismatch currently limit the performance of heteroepitaxial InP cells by introducing shunting paths across the active junction and by the formation of deep traps within the base region. We have previously demonstrated that plasma hydrogenation is an effective and stable means to passivate the electrical activity of such defects in specially designed heteroepitaxial InP test structures to probe hydrogen passivation at typical base depths within a cell structure. In this work, we present our results on the hydrogen passivation of actual heteroepitaxial n(+)p and p(+)n InP cell structures grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD). We have found that a 2 hour exposure to a 13.56 MHz hydrogen plasma at 275 C reduces the deep level concentration in the base regions of both n(+)p and p(+)n heteroepitaxial InP cell structures from as-grown values of 5 - 7 x 10(exp 14)/cc, down to 3 - 5 x 10(exp 12)/cc. All dopants were successfully reactivated by a 400 C, 5 minute anneal With no detectable activation of deep levels. I-V analysis indicated a subsequent approx. 100 fold decrease In reverse leakage current at -1 volt reverse bias, and an improved built in voltage for the p(+)n structures. ln addition to being passivated,dislocations are also shown to participate in secondary interactions during hydrogenation. We find that the presence of dislocations enhances hydrogen diffusion into the cell structure, and lowers the apparent dissociation energy of Zn-H complexes from 1.19 eV for homoepitaxial Zn-doped InP to 1.12 eV for heteroepitaxial Zn-doped InP. This is explained by additional hydrogen trapping at dislocations subsequent to the reactivation of Zn dopants after hydrogenation.

  20. Obtaining of high-quality InP active layers in geterostructure’s composition for Gunn diodes

    Directory of Open Access Journals (Sweden)

    Vakiv M. M.

    2010-06-01

    Full Text Available It is shown that for epitaxial InP layers obtained by liquid-phase epitaxy complex dopping of indium melts by optimal concentrations of rare-earth Yb and isovalent element Al promotes useful increase of cleaning effect from background impurities and leads to growth of its structural perfection. The concentration of electrons in InP layers decreases and their mobility increases on optimal amounts of Yb and Al in the melt. This technology may be used in producing structures for Gunn diodes, photoreceivers and other optoelectronic devices.

  1. Impact of substrate-induced strain and surface effects on the optical properties of InP nanowires

    Science.gov (United States)

    Anufriev, Roman; Chauvin, Nicolas; Khmissi, Hammadi; Naji, Khalid; Gendry, Michel; Bru-Chevallier, Catherine

    2012-08-01

    Wurtzite InP nanowires (NWs), transferred onto various substrates, were investigated by low temperature micro-photoluminescence. A clear PL emission shift, depending on the substrate, is observed and attributed to the substrate-induced strain, generated due to the difference in the thermal expansion coefficients of the InP NWs and the host-substrate during the sample cooling. Moreover, a blueshift of the PL emission peak is observed as the excitation power is increased. This effect, which is not observed on the as-grown sample, is thus a consequence of the host substrate and not an intrinsic property of the nanowires.

  2. InP Self Assembled Quantum Dot Lasers Grown on GaAs Substrates by Metalorganic Chemical Vapor Deposition

    Science.gov (United States)

    2002-01-01

    GaAs (100) substrates by MOCVD. InP quantum dots grown on In(0.5)Al(0.3)Ga(0.2)P have a high density on the order of about 1 - 2 x 10/sq cm with a...dominant size of about 10-15 nm for 7.5 ML growth. (1) These In(0.5)Al(0.3)Ga(0.2)P/ InP quantum dots have previously been characterized by atomic-force

  3. Concepts for connectivity and interoperability of world space data networks: INPE proposal to CCSDS/Panel 3

    Science.gov (United States)

    Bergamini, E. W.

    1983-05-01

    Concepts are presented for an architectural end-to-end reference model based on the identification of classes of applications and products to be offered by services required to exchange data in operational support of space data systems. An Internetwork Transfer Frame (ITF) structure and basic concepts of a protocol are proposed for operational interconnection of data networks. The upward compatibility of these concepts with the higher layers of a standard data interchange structure (SDIS) model is also considered, based on INPE proposal to CCSDS/PANEL 2. Implementation aspects of the proposed model are also presented with respect to INPE's network.

  4. Single-photon emission from InAsP quantum dots embedded in density-controlled InP nanowires

    Science.gov (United States)

    Yanase, Shougo; Sasakura, Hirotaka; Hara, Shinjiro; Motohisa, Junichi

    2017-04-01

    We attempted to control the density and size of InP-based nanowires (NWs) and nanowire quantum dots (NW-QDs) during selective-area metalorganic vapor phase epitaxy. InP nanowire arrays with a 5 µm pitch and an average NW diameter d of 67 nm were successfully grown by optimization of growth conditions. InAsP quantum dots were embedded in these density-controlled InP NW arrays, and clear single-photon emission and exciton-biexciton cascaded emission were confirmed by excitation-dependent photoluminescence and photon correlation measurements.

  5. Growth and characterization of epitaxial SrF2 on InP(100)

    Science.gov (United States)

    Sinharoy, S.; Hoffman, R. A.; Rieger, J. H.; Warner, J. D.; Bhasin, K. B.

    1986-01-01

    The epitaxial growth of 100-262.5-nm SrF2 films on n-type and p-type (100)InP in a conventional baked UHV system at base pressure about 200 ptorr, temperature 250-350 C, and growth rate from less than 100 to about 200 pm/s. Substrates are chemicomechanically polished, degreased, bombarded with 500-eV Ar ions for 3-4 min at 350 C, and annealed for 23-30 min at 350 C, producing a slightly In-rich (In/P = 1.02) In-island-free surface with a (4 x 1) or (1 x 1) LEED structure. Films grown at 350 C and less than 100 pm/s are found to be smooth and free of cracks in most cases, with a highly faceted (1 x 1) LEED structure. The electrical properties of the SrF2 films are found to be acceptable only when the ohmic contacts are applied prior to the substrate prior to SrF2 growth.

  6. Raman investigations on nitrogen ion implantation effects on semi-insulating InP

    CERN Document Server

    Santhakumar, K; Kesavamoorthy, R; Magudapathy, P; Nair, K G M; Ravichandran, V

    2002-01-01

    Raman scattering measurements on liquid-encapsulated Czochralski-grown Fe-doped semi-insulating InP(1 0 0) single crystal substrates have been carried out before and after 120 keV N sup + implantation for various doses from 10 sup 1 sup 3 to 10 sup 1 sup 5 cm sup - sup 2 and also after post-implantation rapid thermal annealing of these samples. It is observed that LO phonon mode frequency decreases and full width at half maximum (FWHM) increases with fluence due to implantation-induced lattice damage. Forbidden Raman TO mode in (1 0 0) cut InP is observed at the doses of 5x10 sup 1 sup 3 and 5x10 sup 1 sup 4 cm sup - sup 2. This might have appeared due to the polycrystalline and/or misoriented regions created during implantation. TO mode is not observed for high doses in as-implanted samples due to excessive lattice damage induced by the implantation. On rapid thermal annealing at 573 K for 30 s, the implanted samples show a partial recovery of LO phonon mode frequency and FWHM due to partial annealing of the...

  7. The design and manufacture of a notch structure for a planar InP Gunn diode

    Institute of Scientific and Technical Information of China (English)

    Bai Yang; Jia Rui; Wu De-Qi; Jin Zhi; Liu Xin-Yu

    2013-01-01

    A planar InP-based Gunn diode with a notch doping structure is designed and fabricated for integration into millimeter-wave and terahertz integrated circuits.We design two kinds of InP-based Gunn diodes.One has a fixed diameter of cathode area,but has variable spacing between anode and cathode; the other has fixed spacing,but a varying diameter.The threshold voltage and saturated current exhibit their strong dependences on the spacing (10 μm-20 μm) and diameter (40 μm-60 μm) of the InP Gunn diode.The threshold voltage is approximately 4.5 V and the saturated current is in a range of 293 mA-397 mA.In this work,the diameter of the diode and the space between anode and cathode are optimized.The devices are fabricated using a wet etching technique and show excellent performances.The results strongly suggest that low-cost and reliable InP planar Gunn diodes can be used as single chip terahertz sources.

  8. The effect of nitrogen implantation on structural changes in semi-insulating InP

    Energy Technology Data Exchange (ETDEWEB)

    Santhakumar, K.; Jayavel, P.; Reddy, G.L.N.; Sastry, V.S.; Nair, K.G.M.; Ravichandran, V. E-mail: vravichandran@vsnl.com

    2003-12-01

    110 keV nitrogen ions (N{sup +}) of fluences 1 x 10{sup 14}-1 x 10{sup 17} cm{sup -2} have been implanted in liquid encapsulated Czochralski grown Fe-doped semi-insulating indium phosphide (InP) single crystal substrates. Grazing incidence X-ray diffraction measurements on as-grown and implanted samples have been carried out and analyzed. At all above fluences, a broad hump in the region of InP(1 1 1) peaks is observed. It might have resulted from implantation-induced misoriented grains along certain preferred orientations. The peak observed at a d-value of 1.77 A for all the fluences becomes more pronounced as the implantation fluence increases up to 1 x 10{sup 16} cm{sup -2}. This could indicate formation of an Indium phosphide nitride alloy. Post-implantation annealing reduces the structural defects and assists in the growth of the nitride phase.

  9. The design and manufacture of a notch structure for a planar InP Gunn diode

    Science.gov (United States)

    Bai, Yang; Jia, Rui; Wu, De-Qi; Jin, Zhi; Liu, Xin-Yu

    2013-02-01

    A planar InP-based Gunn diode with a notch doping structure is designed and fabricated for integration into millimeter-wave and terahertz integrated circuits. We design two kinds of InP-based Gunn diodes. One has a fixed diameter of cathode area, but has variable spacing between anode and cathode; the other has fixed spacing, but a varying diameter. The threshold voltage and saturated current exhibit their strong dependences on the spacing (10 μm-20 μm) and diameter (40 μm-60 μm) of the InP Gunn diode. The threshold voltage is approximately 4.5 V and the saturated current is in a range of 293 mA-397 mA. In this work, the diameter of the diode and the space between anode and cathode are optimized. The devices are fabricated using a wet etching technique and show excellent performances. The results strongly suggest that low-cost and reliable InP planar Gunn diodes can be used as single chip terahertz sources.

  10. Conductivity, Hall and magnetoresistance effect measurements on SI GaAs and InP

    Energy Technology Data Exchange (ETDEWEB)

    Acar, S.; Kasap, M. [Department of Physics, Faculty of Science and Arts, University of Gazi, Teknikokullar, 06500 Ankara (Turkey)

    2004-05-01

    The conductivity, Hall effect and magnetoresistance quantities in semi-insulating undoped GaAs and Fe-doped GaAs and InP grown by the LEC technique have been measured in the temperature range 300-420 K. It is shown that mixed conductivity is present in all samples. The experimental data were analyzed using a two-band model including electron and hole transport. A good fit has been obtained self-consistently to both conductivity and mobility. The single-band parameters have been extracted from the measured data in the studied temperature range. From ln (vertical stroke R{sub H,} {sub 0} vertical stroke T {sup 3/2}) and {sigma} vs T {sup -1} plots, activation energies of 0.77 and 0.65 eV have also been observed for GaAs and InP, respectively. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. TP53INP1, a tumor suppressor, interacts with LC3 and ATG8-family proteins through the LC3-interacting region (LIR) and promotes autophagy-dependent cell death.

    Science.gov (United States)

    Seillier, M; Peuget, S; Gayet, O; Gauthier, C; N'Guessan, P; Monte, M; Carrier, A; Iovanna, J L; Dusetti, N J

    2012-09-01

    TP53INP1 (tumor protein 53-induced nuclear protein 1) is a tumor suppressor, whose expression is downregulated in cancers from different organs. It was described as a p53 target gene involved in cell death, cell-cycle arrest and cellular migration. In this work, we show that TP53INP1 is also able to interact with ATG8-family proteins and to induce autophagy-dependent cell death. In agreement with this finding, we observe that TP53INP1, which is mainly nuclear, relocalizes in autophagosomes during autophagy where it is eventually degraded. TP53INP1-LC3 interaction occurs via a functional LC3-interacting region (LIR). Inactivating mutations of this sequence abolish TP53INP1-LC3 interaction, relocalize TP53INP1 in autophagosomes and decrease TP53INP1 ability to trigger cell death. Interestingly, TP53INP1 binds to ATG8-family proteins with higher affinity than p62, suggesting that it could partially displace p62 from autophagosomes, modifying thereby their composition. Moreover, silencing the expression of autophagy related genes (ATG5 or Beclin-1) or inhibiting caspase activity significantly decreases cell death induced by TP53INP1. These data indicate that cell death observed after TP53INP1-LC3 interaction depends on both autophagy and caspase activity. We conclude that TP53INP1 could act as a tumor suppressor by inducing cell death by caspase-dependent autophagy.

  12. Submicron InP DHBT technology for high-speed high-swing mixed-signal ICs

    DEFF Research Database (Denmark)

    Godin, Jean; Nodjiadjim, V.; Riet, Muriel;

    2008-01-01

    We report on the development of a submicron InP DHBT technology, optimized for the fabrication of 50-GHz-clock mixed signal ICs. In-depth study of device geometry and structure has allowed to get the needed performances and yield. Special attention has been paid to critical thermal behavior. Vari...

  13. Design of InP DHBT power amplifiers at millimeter-wave frequencies using interstage matched cascode technique

    DEFF Research Database (Denmark)

    Yan, Lei; Johansen, Tom Keinicke

    2013-01-01

    In this paper, the design of InP DHBT based millimeter-wave(mm-wave) power amplifiers(PAs) using an interstage matched cascode technique is presented. The output power of a traditional cascode is limited by the early saturation of the common-base(CB) device. The interstage matched cascode can be ...

  14. Improvement of GaAsSb alloys on InP grown by molecular beam epitaxy with substrate tilting

    Science.gov (United States)

    Chou, C. Y.; Torfi, A.; Wang, W. I.

    2013-10-01

    GaAsSb alloys lattice-matched to InP substrate have been used in various electronic and optoelectronic applications due to their highly desirable band alignment for high-speed double heterojunction bipolar transistors. There is however an issue with GaAsSb alloys, composed approximately of 50% As and 50% Sb, lattice-matched to an InP substrate; it exhibits a miscibility gap, which is a significant problem for crystal growth. This paper addresses the effect of substrate tilting on the material properties of GaAsSb alloys closely lattice-matched to InP substrates by molecular beam epitaxy (MBE). InP(100) substrates tilted 0°off-(on-axis), 2°off-, 3°off-, and 4°off-axis were used for MBE growth, then the material qualities of GaAsSb epitaxial layers were compared using various techniques, including high resolution X-ray diffraction, photoluminescence (PL), Raman scattering, and transmission-line measurements (TLM). Substrate tilting improved the GaAsSb alloys with crystalline quality, shown by a narrower x-ray linewidth and enhanced optical quality as evidenced by a strong PL peak. The results of TLM show that the lowest sheet resistance was achieved at a 2° off-axis tilt. The results are expected to be applicable in devices that incorporate GaAsSb in the active layer grown by MBE.

  15. Solvothermal synthesis of InP quantum dots and their enhanced luminescent efficiency by post-synthetic treatments.

    Science.gov (United States)

    Byun, Ho-June; Lee, Ju Chul; Yang, Heesun

    2011-03-01

    InP quantum dots (QDs) were solvothermally synthesized by using a greener phosphorus source of P(N(CH(3))(2))(3) instead of highly toxic P(TMS)(3) widely used, and subsequently subjected to a size-sorting processing. While as-grown QDs showed an undetectably low emission intensity, post-synthetic treatments such as photo-etching, photo-radiation, and photo-assisted ZnS shell coating gave rise to a substantial increase in emission efficiency due to the effective removal and passivation of surface states. The emission efficiency of the photo-etched QDs was further enhanced by a consecutive UV photo-radiation, attributable to the photo-oxidation at QD surface. Furthermore, a relatively thick ZnS shell on the surface of InP QDs that were surface-modified with hydrophilic ligands beforehand was photochemically generated in an aqueous solution at room temperature. The resulting InP/ZnS core/shell QDs, emitting from blue to red wavelengths, were more efficient than the above photo-treated InP QDs, and their luminescent properties (emission bandwidth and quantum yield) were comparable to those of InP QDs synthesized with P(TMS)(3). Structural, size, and compositional analyses on InP/ZnS QDs were also conducted to elucidate their core/shell structure.

  16. A high conversion-gain Q-band InP DHBT subharmonic mixer using LO frequency doubler

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Vidkjær, Jens; Krozer, Viktor;

    2008-01-01

    The paper presents analysis and design of a Q-band subharmonic mixer (SHM) with high conversion gain. The SHM consists of a local oscillator (LO) frequency doubler, RF pre-amplifier, and single-ended mixer. The SHM has been fabricated in a high-speed InP double heterojunction bipolar transistor...

  17. Modeling, design, fabrication, and testing of InP Gunn devices in the D-band (110 GHz - 170 GHz)

    Science.gov (United States)

    Kamoua, R.; Eisele, H.; East, J. R.; Haddad, G. I.; Munns, G.; Sherwin, M.

    1992-01-01

    The development of fundamental Gunn sources for D-band frequencies requires improvements of doping profiles, processing technology, and circuit design. We have developed a technology for fabricating InP Gunn diodes using an InGaAs etch-stop layer between the InP substrate and the device layers. The epitaxial layers were grown by CBE. During device processing, the substrate is completely removed. Substrateless devices with an n(+) InGaAs cap layer are expected to have reduced contact and series resistances, and skin effect losses. This technology gives better uniformity and control of the device geometry across the processed chip. InP Gunn devices with a 1.7 micron long active region (doping : 9 x 10(exp 15) cm(exp -3)) have been mounted on copper heat sinks. Two tapered leads were then bonded to the diode and to four quartz standoffs. As a preliminary result, an output power of 13 mW at 82 GHz was obtained. Based on these RF measurements, we determine appropriate material parameters to be used in the Ensemble Monte Carlo model. Subsequently, we use this model to design and evaluate the performance of InP Gunn Devices for D-band frequencies. Using the same technology, we are currently processing Gunn devices with a 1 micron long active region for operation at higher frequencies.

  18. 1.12 Tb/s superchannel coherent PM-QPSK InP transmitter photonic integrated circuit (PIC).

    Science.gov (United States)

    Evans, P; Fisher, M; Malendevich, R; James, A; Goldfarb, G; Vallaitis, T; Kato, M; Samra, P; Corzine, S; Strzelecka, E; Studenkov, P; Salvatore, R; Sedgwick, F; Kuntz, M; Lal, V; Lambert, D; Dentai, A; Pavinski, D; Zhang, J; Cornelius, J; Tsai, T; Behnia, B; Bostak, J; Dominic, V; Nilsson, A; Taylor, B; Rahn, J; Sanders, S; Sun, H; Wu, K-T; Pleumeekers, J; Muthiah, R; Missey, M; Schneider, R; Stewart, J; Reffle, M; Butrie, T; Nagarajan, R; Ziari, M; Kish, F; Welch, D

    2011-12-12

    In this work, a 10-wavelength, polarization-multiplexed, monolithically integrated InP coherent QPSK transmitter PIC is demonstrated to operate at 112 Gb/sec per wavelength and total chip superchannel bandwidth of 1.12 Tb/s. This demonstration suggests that increasing data capacity to multi-Tb/s per chip is possible and likely in the future.

  19. Electrical and structural characterization of GaAs on InP grown by OMCVD; application to GaAs MESFETs

    Science.gov (United States)

    Azoulay, R.; Clei, A.; Dugrand, L.; Draïdia, auN.; Leroux, G.; Biblemont, S.

    1991-01-01

    The growth of GaAs on InP has attracted considerable interest recently because of the possibility of integration of GaAs electronic devices and 1.3 μm optical devices on the same wafer. In this work, we have investigated the growth of GaAs MESFETs and doped channel MIS-like FETs on InP by atmospheric pressure OMCVD. Because of the difference between the thermal expansion coefficient of GaAs and InP, the layers are under biaxial strain. The lowest FWHM of the (004) reflection curve of the double crystal X-ray diffraction spectra is 110 arc sec for a 12 μm thick layer. We have investigated the influence of the substrate temperature and of the arsine molar fraction on the residual carrier concentration of layers grown side by side on GaAs and on InP. The GaAs layers grown on InP are much more compensated than the layers grown on GaAs, indicating a higher incorporation of impurities. On MESFETs grown on InP, gm = 200mS/mm with Fmax higher than 30 GHz. On doped-channel MIS-like FETs on InP, we have measured gm = 145mS/mm.

  20. Hydrogen passivation of n+p and p+n heteroepitaxial InP solar cell structures

    Science.gov (United States)

    Chatterjee, B.; Ringel, S. A.; Hoffman, R., Jr.

    1995-01-01

    High-efficiency, heteroepitaxial (HE) InP solar cells, grown on GaAs, Si or Ge substrates, are desirable for their mechanically strong, light-weight and radiation-hard properties. However, dislocations, caused by lattice mismatch, currently limit the performance of the HE cells. This occurs through shunting paths across the active photovoltaic junction and by the formation of deep levels. In previous work we have demonstrated that plasma hydrogenation is an effective and stable means to passivate the electrical activity of dislocations in specially designed HE InP test structures. In this work, we present the first report of successful hydrogen passivation in actual InP cell structures grown on GaAs substrates by metalorganic chemical vapor deposition (MOCVD). We have found that a 2 hour exposure to a 13.56 MHz hydrogen plasma at 275 C reduces the deep level concentration in HE n+n InP cell structures from as-grown values of approximately 10(exp 15)/cm(exp -3), down to 1-2 x 10(exp 13)/cm(exp -3). The deep levels in the p-type base region of the cell structure match those of our earlier p-type test structures, which were attributed to dislocations or related point defect complexes. All dopants were successfully reactivated by a 400 C, 5 minute anneal with no detectable activation of deep levels. I-V analysis indicated a subsequent approximately 10 fold decrease in reverse leakage current at -1 volt reverse bias, and no change in the forward biased series resistance of the cell structure which indicates complete reactivation of the n+ emitter. Furthermore, electrochemical C-V profiling indicates greatly enhanced passivation depth, and hence hydrogen diffusion, for heteroepitaxial structures when compared with identically processed homoepitaxial n+p InP structures. An analysis of hydrogen diffusion in dislocated InP will be discussed, along with comparisons of passivation effectiveness for n+p versus p+n heteroepitaxial cell configurations. Preliminary hydrogen

  1. Formulation of the microbicide INP0341 for in vivo protection against a vaginal challenge by Chlamydia trachomatis.

    Directory of Open Access Journals (Sweden)

    Christian Pedersen

    Full Text Available The salicylidene acylhydrazide (SA compounds have exhibited promising microbicidal properties. Previous reports have shown the SA compounds, using cell cultures, to exhibit activity against Chlamydia trachomatis, herpes simplex virus and HIV-1. In addition, using an animal model of a vaginal infection the SA compound INP0341, when dissolved in a liquid, was able to significantly protect mice from a vaginal infection with C. trachomatis. To expand upon this finding, in this report INP0341 was formulated as a vaginal gel, suitable for use in humans. Gelling agents (polymers with inherent antimicrobial properties were chosen to maximize the total antimicrobial effect of the gel. In vitro formulation work generated a gel with suitable rheology and sustained drug release. A formulation containing 1 mM INP0341, 1.6 wt% Cremophor ELP (solubility enhancer and 1.5 wt% poly(acrylic acid (gelling and antimicrobial agent, was chosen for studies of efficacy and toxicity using a mouse model of a vaginal infection. The gel formulation was able to attenuate a vaginal challenge with C. trachomatis, serovar D. Formulations with and without INP0341 afforded protection, but the inclusion of INP0341 increased the protection. Mouse vaginal tissue treated with the formulation showed no indication of gel toxicity. The lack of toxicity was confirmed by in vitro assays using EpiVaginal tissues, which showed that a 24 h exposure to the gel formulation did not decrease the cell viability or the barrier function of the tissue. Therefore, the gel formulation described here appears to be a promising vaginal microbicide to prevent a C. trachomatis infection with the potential to be expanded to other sexually transmitted diseases.

  2. AES, EELS and TRIM simulation method study of InP(100 subjected to Ar+, He+ and H+ ions bombardment.

    Directory of Open Access Journals (Sweden)

    Abidri B.

    2012-06-01

    Full Text Available Auger Electron Spectroscopy (AES and Electron Energy Loss Spectroscopy (EELS have been performed in order to investigate the InP(100 surface subjected to ions bombardment. The InP(100 surface is always contaminated by carbon and oxygen revealed by C-KLL and O-KLL AES spectra recorded just after introduction of the sample in the UHV spectrometer chamber. The usually cleaning process of the surface is the bombardment by argon ions. However, even at low energy of ions beam (300 eV indium clusters and phosphorus vacancies are usually formed on the surface. The aim of our study is to compare the behaviour of the surface when submitted to He+ or H+ ions bombardment. The helium ions accelerated at 500V voltage and for 45 mn allow removing contaminants but induces damaged and no stoichiometric surface. The proton ions were accelerated at low energy of 500 eV to bombard the InP surface at room temperature. The proton ions broke the In-P chemical bonds to induce the formation of In metal islands. Such a chemical reactivity between hydrogen and phosphorus led to form chemical species such as PH and PH3, which desorbed from the surface. The chemical susceptibly and the small size of H+ advantaged their diffusion into bulk. Since the experimental methods alone were not able to give us with accuracy the disturbed depth of the target by these ions. We associate to the AES and EELS spectroscopies, the TRIM (Transport and Range of Ions in Matter simulation method in order to show the mechanism of interaction between Ar+, He+ or H+ ions and InP and determine the disturbed depth of the target by argon, helium or proton ions.

  3. The effect of bulk traps on the InP (Indium Phosphide) accumulation type MISFET (Metal-Insulator-Semiconductor Field-Effect Transistor)

    Science.gov (United States)

    Meiners, L. G.

    The enclosed reports represent work performed at USCD on Contract N00014-82-K-2032 entitled Surface and Interfacial Properties of InP and provides a full account of the results obtained during the contract period: May 1, 1984 through April 31, 1985. The paper, Space charge-limited currents and trapping in semi-insulating InP, has now been published in Electron. Device Letters, volume EDL-6, page 356 (1985). The manuscript, Effect of bulk traps on the InP accumulation type MISFET, will be presented as an invited talk at the fall meeting in the Journal of the Electrochemical Society.

  4. InP MMIC Chip Set for Power Sources Covering 80-170 GHz

    Science.gov (United States)

    Ngo, Catherine

    2001-01-01

    We will present a Monolithic Millimeter-wave Integrated Circuit (MMIC) chip set which provides high output-power sources for driving diode frequency multipliers into the terahertz range. The chip set was fabricated at HRL Laboratories using a 0.1-micrometer gate-length InAlAs/InGaAs/InP high electron mobility transistor (HEMT) process, and features transistors with an f(sub max) above 600 GHz. The HRL InP HEMT process has already demonstrated amplifiers in the 60-200 GHz range. In this paper, these high frequency HEMTs form the basis for power sources up to 170 GHz. A number of state-of-the-art InP HEMT MMICs will be presented. These include voltage-controlled and fixed-tuned oscillators, power amplifiers, and an active doubler. We will first discuss an 80 GHz voltage-controlled oscillator with 5 GHz of tunability and at least 17 mW of output power, as well as a 120 GHz oscillator providing 7 mW of output power. In addition, we will present results of a power amplifier which covers the full WRIO waveguide band (75-110 GHz), and provides 40-50 mW of output power. Furthermore, we will present an active doubler at 164 GHz providing 8% bandwidth, 3 mW of output power, and an unprecedented 2 dB of conversion loss for an InP HEMT MMIC at this frequency. Finally, we will demonstrate a power amplifier to cover 140-170 GHz with 15-25 mW of output power and 8 dB gain. These components can form a power source in the 155-165 GHz range by cascading the 80 GHz oscillator, W-band power amplifier, 164 GHz active doubler and final 140-170 GHz power amplifier for a stable, compact local oscillator subsystem, which could be used for atmospheric science or astrophysics radiometers.

  5. Hole Rashba effect and g-factor in InP nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X W [Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 100083 (China); Xia, J B [Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 100083 (China)

    2007-01-21

    The hole Rashba effect and g-factor in InP nanowires in the presence of electric and magnetic fields which bring spin splitting are investigated theoretically in the framework of eight-band effective-mass envelop function theory, by expanding the lateral wave function in Bessel functions. It is well known that the electron Rashba coefficient increases nearly linearly with the electric field. As the Rashba spin splitting is zero at zero k{sub z} (the wave vector along the wire direction), the electron g-factor at k{sub z} = 0 changes little with the electric field. While we find that as the electric field increases, the hole Rashba coefficient increases at first, then decreases. It is noticed that the hole Rashba coefficient is zero at a critical electric field. The hole g-factor at k{sub z} = 0 changes obviously with the electric field.

  6. Effect of native oxide mechanical deformation on InP nanoindentation

    Science.gov (United States)

    Almeida, C. M.; Prioli, R.; Ponce, F. A.

    2008-12-01

    Native oxide has been found to have a noticeable effect on the mechanical deformation of InP during nanoindentation. The indentations were performed using spherical diamond tips and the residual impressions were studied by atomic force microscopy. It has been observed that in the early stages of mechanical deformation, plastic flow occurs in the oxide layer while the indium phosphide is still in the elastic regime. The deformed native oxide layer results in a pile-up formation that causes an increase in the contact area between the tip and the surface during the nanoindentation process. This increase in the projected contact area is shown to contribute to the apparent high pressure sustained by the crystal before the onset of plastic deformation. It is also shown that the stress necessary to generate the first dislocations from the crystal surface is ˜3 GPa higher than the stress needed for slip to occur when dislocations are already present in the crystalline structure.

  7. Photovoltaic characteristics of n(+)pp(+) InP solar cells grown by OMVPE

    Science.gov (United States)

    Tyagi, S.; Singh, K.; Bhimnathwala, H.; Ghandhi, S. K.; Borrego, J. M.

    1990-01-01

    The photovoltaic characteristics of n(+)/p/p(+) homojunction InP solar cells fabricated by organometallic vapor-phase epitaxy (OMVPE) are described. The cells are characterized by I-V, C-V and quantum efficiency measurements, and simulations are used to obtain various device and material parameters. The I-V characteristics show a high recombination rate in the depletion region; this is shown to be independent of the impurity used. It is shown that cadmium is easier to use as an acceptor for the p base and p(+) buffer and is therefore beneficial. The high quantum efficiency of 98 percent at long wavelengths measured in these cells indicates a very good collection efficiency in the base. The short-wavelength quantum efficiency is poor, indicating a high surface recombination.

  8. Identification of vacancy type defects in low and high energy nitrogen ion implanted InP

    Energy Technology Data Exchange (ETDEWEB)

    Santhakumar, K [Department of Nuclear Physics, University of Madras, Chennai - 600025 (India); Rao, G Venugopal [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102 (India); Amarendra, G [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102 (India); Abhaya, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102 (India); Sastry, V Sankara [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102 (India); Nair, K G M [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102 (India); Ravichandran, V [Department of Nuclear Physics, University of Madras, Chennai - 600025 (India)

    2005-12-21

    Depth resolved positron annihilation measurements were carried out on 85 keV and 1 MeV nitrogen ion implanted InP samples. The defect sensitive S-parameter and R-parameter values for the low energy implantations confirm the presence of monovacancies up to a dose of 10{sup 15} cm{sup -2} and coexistence of monovacancies and divacancies for 10{sup 16} cm{sup -2} dose sample. Corroborative glancing incidence x-ray diffraction measurements on the highest dose sample revealed that the sample is amorphized. For high energy implantation, it is found that vacancy-defects are present right from the near-surface region and these defects are identified to be monovancancies, based on the observed S- and R-parameters. A comparison of the results for the low and high energy implantations is made.

  9. Fluorescence intermittency in self-assembled InP quantum dots.

    Science.gov (United States)

    Sugisaki, M; Ren, H W; Nishi, K; Masumoto, Y

    2001-05-21

    Fluorescence intermittency in InP self-assembled dots is investigated by means of far field imaging and single dot spectroscopy. Based on our observation that blinking dots are found in the vicinity of scratches and the blinking frequency is drastically enhanced under a near-infrared laser irradiation, we attribute the origin of the fluorescence intermittency to a local electric field due to a carrier trapped at a deep localized center in the Ga0.5In0.5P matrix. The validity of this explanation is confirmed by a thermal activation-type behavior of the switching rate and artificial reproduction of the blinking phenomenon by an external electric field.

  10. Exciton fine structure splitting in InP quantum dots in GaInP.

    Science.gov (United States)

    Ellström, C; Seifert, W; Pryor, C; Samuelson, L; Pistol, M-E

    2007-07-25

    We have investigated the electronic structure of excitons in InP quantum dots in GaInP. The exciton is theoretically expected to have four states. Two of the states are allowed to optically decay to the ground (vacuum) state in the dipole approximation. We see these two lines in photoluminescence (PL) experiments and find that the splitting between the lines (the fine structure splitting) is 150(± 30) µeV. The lines were perpendicularly polarized. We verified that the lines arise from neutral excitons by using correlation spectroscopy. The theoretical calculations show that the polarization of the emission lines are along and perpendicular to the major axis of elongated dots. The fine structure splitting depends on the degree of elongation of the dots and is close to zero for dots of cylindrical symmetry, despite the influence of the piezoelectric polarization, which is included in the calculation.

  11. Experimentally estimated dead space for GaAs and InP based planar Gunn diodes

    Science.gov (United States)

    Ismaeel Maricar, Mohamed; Khalid, A.; Dunn, G.; Cumming, D.; Oxley, C. H.

    2015-01-01

    An experimental method has been used to estimate the dead space of planar Gunn diodes which were fabricated using GaAs and InP based materials, respectively. The experimental results indicate that the dead space was approximately 0.23 μm and the saturation domain velocity 0.96 × 105 m s-1 for an Al0.23Ga0.77As based device, while for an In0.53Ga0.47As based device, the dead space was approximately 0.21 μm and the saturation domain velocity 1.93 × 105 m s-1. Further, the results suggest that the saturation domain velocity is reduced or there is an increase in the dead-space due to local field distortions when the active channel length of the planar Gunn diode is less than 1 micron.

  12. InP nanowire p-type doping via Zinc indiffusion

    Science.gov (United States)

    Haggren, Tuomas; Otnes, Gaute; Mourão, Renato; Dagyte, Vilgaile; Hultin, Olof; Lindelöw, Fredrik; Borgström, Magnus; Samuelson, Lars

    2016-10-01

    We report an alternative pathway for p-type InP nanowire (NW) doping by diffusion of Zn species from the gas phase. The diffusion of Zn was performed in a MOVPE reactor at 350-500 °C for 5-20 min with either H2 environment or additional phosphorus in the atmosphere. In addition, Zn3P2 shells were studied as protective caps during post-diffusion annealing. This post-diffusion annealing was performed to outdiffuse and activate Zn in interstitial locations. The characterization methods included photoluminescence and single NW conductivity and carrier concentration measurements. The acquired carrier concentrations were in the order of >1017 cm-3 for NWs without post-annealing, and up to 1018 cm-3 for NWs annealed with the Zn3P2 shells. The diffused Zn caused redshift to the photoluminescence signal, and the degree of redshift depended on the diffusion process.

  13. High Magnetic Field Superconducting Magnets Fabricated In Budker Inp For Sr Generation

    CERN Document Server

    Zolotarev, K V; Khruschev, S V; Krämer, Dietrich; Kulipanov, G N; Lev, V H; Mezentsev, N A; Miginsky, E G; Shkaruba, V A; Syrovatin, V M; Tsukanov, V M; Zjurba, V K

    2004-01-01

    BESSY operates a 3-rd generation synchrotron light source in VUV to XUV region at Berlin-Adlershof. The main radiation sources in storage ring are special magnetic elements as undulators and wigglers. 3 superconducting shifters and one multipole superconducting wiggler are operating giving enhanced photon flux for 10-25 keV X-ray region. As the superconducting elements presently are located in straight sections, BESSY intends to exchange 4 of conventional room-temperature bending magnets by superconducting ones.The report contains brief description of 9 Tesla superbend prototype as a candidate for replacing of conventional magnets of BESSY-2, which was designed, fabricated and tested at Budker INP and was commissioned at BESSY in June 2004.Main parameters of 9 Tesla superconducting bending magnet prototype as well as testing results are presented.

  14. Si Incorporation in InP Nanowires Grown by Au-Assisted Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Lorenzo Rigutti

    2009-01-01

    Full Text Available We report on the growth, structural characterization, and conductivity studies of Si-doped InP nanowires grown by Au-assisted molecular beam epitaxy. It is shown that Si doping reduces the mean diffusion length of adatoms on the lateral nanowire surface and consequently reduces the nanowire growth rate and promotes lateral growth. A resistivity as low as 5.1±0.3×10−5 Ω⋅cm is measured for highly doped nanowires. Two dopant incorporation mechanisms are discussed: incorporation via catalyst particle and direct incorporation on the nanowire sidewalls. The first mechanism is shown to be less efficient than the second one, resulting in inhomogeneous radial dopant distribution.

  15. Photonics integrations enabling high-end applications of InP in optical data transmissions

    Science.gov (United States)

    Zhang, Jiaming; Frateschi, Newton; Jambunathan, Ram; Choi, Wonjin; Bond, Aaron E.

    2005-10-01

    We present here results from a uniquely designed InP modulator chip combined with advanced packaging concepts, which enables high-end applications in optical data communications. An electroabsorption (EA) modulator, with a strained InGaAsP or InGaAlAs multiple quantum well structure, is monolithically integrated with a semiconductor optical amplifier. This design offers broad wavelength tunability while maintaining high extinction ratio, high optical output power, and high dispersion tolerance. The amplified EA modulator chip is co-packaged with a distributed feed back (DFB) laser ensuring separate optimization of the laser and modulator sections. The optical isolator, placed between the laser and modulator, completely eliminates adiabatic chirp. This Telcordia-qualified laser integrated modulator platform enables superior performance previously not thought possible for InP absorption based modulators. 11dB of dynamic extinction ratio, 5dBm of modulated output power, and +/-1200ps/nm or +1600ps/nm dispersion tolerance can be simultaneously achieved in un-amplified 10Gb/s data transmission. Full C-band tunability using a single device is also demonstrated with the LIM module. Extensive simulations and transmission system evaluations shows that with the controllable chirp, the cost-effective LIM performs as well as a Mach-Zehnder modulator in dispersion managed and amplified long-haul WDM systems. Lastly, the first uncooled 10Gb/s long-reach operation at 1550nm was demonstrated with LIM packages. Using a simple control algorithm, a constant modulated output power of 1dBm with less than 1dB dispersion penalty over 1600ps/nm single mode fiber is achieved in an 80 degrees environmental temperature range without any module temperature control. Utilizing the Al-based material system, also allows a reduced variation of the extinction ratio.

  16. 国外InP HEMT和InP HBT的发展现状及应用%Development and Application of InP HEMT and InP HBT

    Institute of Scientific and Technical Information of China (English)

    姚立华

    2009-01-01

    InP device is the first selection in millimeter wave bands because for its high frequency, high power, low noise figure and radiation hardened. InP HEMT and InP HBT behave excellent performance in military applications, such as satellite and radar. Current development, excellent performances and the main manufacturers of InP HEMT/InP HBT devices and circuits are presented. InP HEMT according to low noise and power is described. Their applications in military are introduced, for instance in T/R module of satellite phase array radar system, receivers in spacecraft and ground based station and communication systems. The development trends are summarized according to the development of InP device and circuits abroad.%在毫米波段,InP基器件由于其具有高频、高功率、低噪声及抗辐射等特点,成为人们的首选,尤其适用于空间应用.InP HEMT和InP HBT已在卫星、雷达等军事应用中表现出了优异的性能.分别介绍了InP HEMT和InP HBT器件及电路的发展现状,现在能达到的最高性能及主要生产公司等,其中InP HEMT又分别按低噪声和功率进行了详细介绍.介绍了它们在军事上的主要应用,以具体的应用实例介绍了在卫星相控阵雷达系统天线中的T/R模块中、航天器和地面站的接收机中、以及雷达和通信系统中的应用情况、达到的性能及可靠性等.并根据国外InP器件和电路的发展现状总结了其未来发展趋势.

  17. A study of the coupling between LO phonons and plasmons in InP p-i-n diodes

    Science.gov (United States)

    Thao, Dinh Nhu

    2017-03-01

    This paper reports a study investigating the coupling between longitudinal optical (LO) phonons and plasmons in InP p-i-n diodes by a numerical simulation. A significant change is observed in the Fourier transform spectra of transient electric field when taking the coupling into account. The findings show two separate peaks instead of a single plasma peak as for non-coupling case. In addition, the bulk-like dispersion relations of the frequencies of those two peaks on the carrier density are found. Therefore, it is proposed that those behaviors manifest the LO phonon-plasmon coupling in the diodes. Also, there is evidence of the peak clipping by the diode itself, a phenomenon not being seen in the bulk InP semiconductor.

  18. Current impulse response of thin InP p+-i-n+ diodes using full band structure Monte Carlo method

    Science.gov (United States)

    You, A. H.; Cheang, P. L.

    2007-02-01

    A random response time model to compute the statistics of the avalanche buildup time of double-carrier multiplication in avalanche photodiodes (APDs) using full band structure Monte Carlo (FBMC) method is discussed. The effect of feedback impact ionization process and the dead-space effect on random response time are included in order to simulate the speed of APD. The time response of InP p+-i-n+ diodes with the multiplication region of 0.2μm is presented. Finally, the FBMC model is used to calculate the current impulse response of the thin InP p+-i-n+ diodes with multiplication lengths of 0.05 and 0.2μm using Ramo's theorem [Proc. IRE 27, 584 (1939)]. The simulated current impulse response of the FBMC model is compared to the results simulated from a simple Monte Carlo model.

  19. Band offset in GaAlAs and InGaAs: InP heterojunctions by electrochemical CV profiling

    Science.gov (United States)

    Furtado, M. T.; Loural, M. S. S.; Sachs, A. C.; Shieh, P. J.

    We report electrochemical CV measurement determination of the conduction band offset ΔEc of Ga 1-xAl xAs:Ga 1-yAl yAs heterojunctions (HJs) with x=0-0.21 and y≈0.4, as well as of In 0.53Ga 0.47As: InP HJs. The samples were grown by liquid phase epitaxy. We have obtained band offset ratios ΔEc/ΔEg≈0.6 and ΔEc/ΔEg≈0.36, respectively, for GaAlAs and InGaAs: InP HJs, where ΔEg is the HJ band gap energy difference. These results are consistent with recent data obtained by other techniques on similar HJs. In addition, the density of fixed interface charges are estimated and are apparently related to the doping of the large band gap layer of the HJ.

  20. Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

    Institute of Scientific and Technical Information of China (English)

    HUANG Lei; SUN Bo; YAO Jian-quan; WANG Peng

    2008-01-01

    The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied.In collinear phase-matching,the optimum phase-matching wave bands of these two crystals are calculated.The optimum phase-matching wave bands in GaAs and InP are 0.95~1.38 μm and 0.7~0.96 μm respectively.The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed.The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed.It can serve for the following experiments as a theoretical evidence and a reference aswell.

  1. Luminescent InP Quantum Dots with Tunable Emission by Post-Synthetic Modification with Lewis Acids.

    Science.gov (United States)

    Stein, Jennifer L; Mader, Elizabeth A; Cossairt, Brandi M

    2016-04-07

    We demonstrate the ability of M(2+) Lewis acids (M = Cd, Zn) to dramatically enhance the photoluminescence quantum yield (PL QY) of InP quantum dots. The addition of cadmium and zinc is additionally found to red- and blue-shift, respectively, the lowest energy absorption and emission of InP quantum dots while maintaining particle size. This treatment results in a facile strategy to post-synthetically tune the luminescence color in these materials. Optical and structural characterization (XRD, TEM, XAS, ICP) have led us to identify the primary mechanism of PL turn-on as surface passivation of phosphorus dangling bonds, affording PL QYs up to 49% without the growth of a type I shell or the addition of HF. This route to PL enhancement and color tuning may prove useful as a standalone treatment or as a complement to shelling strategies.

  2. Characteristics of highly stacked InAs quantum-dot laser grown on vicinal (001)InP substrate

    Science.gov (United States)

    Akahane, Kouichi; Umezawa, Toshimasa; Matsumoto, Atsushi; Yamamoto, Naokatsu; Kawanishi, Tetsuya

    2016-04-01

    We fabricate broad-area laser diodes consisting of 30-layer stacks of InAs quantum dots by using a strain-compensation technique on a vicinal (001)InP substrate. These laser diodes exhibit ground-state lasing at 1576 nm in the pulsed mode with a high characteristic temperature of 111 K at around room temperature (20-80 °C).

  3. Improved dot size uniformity and luminescense of InAs quantum dots on InP substrate

    Science.gov (United States)

    Qiu, Y.; Uhl, D.

    2002-01-01

    InAs self-organized quantum dots have been grown in InGaAs quantum well on InP substrates by metalorganic vapor phase epitaxy. Atomic Force Microscopy confirmed of quantum dot formation with dot density of 3X10(sup 10) cm(sup -2). Improved dot size uniformity and strong room temperature photoluminescence up to 2 micron were observed after modifying the InGaAs well.

  4. Facile synthesis of uniform large-sized InP nanocrystal quantum dots using tris(tert-butyldimethylsilyl)phosphine

    OpenAIRE

    2012-01-01

    Colloidal III-V semiconductor nanocrystal quantum dots [NQDs] have attracted interest because they have reduced toxicity compared with II-VI compounds. However, the study and application of III-V semiconductor nanocrystals are limited by difficulties in their synthesis. In particular, it is difficult to control nucleation because the molecular bonds in III-V semiconductors are highly covalent. A synthetic approach of InP NQDs was presented using newly synthesized organometallic phosphorus [P]...

  5. High electron mobility of modulation doped GaAs after growing InP by solid source molecular beam epitaxy

    Institute of Scientific and Technical Information of China (English)

    SHU Yong-chun; PI Biao; LIN Yao-wang; XING Xiao-dong; YAO Jiang-hong; WANG Zhan-guo; XU Jing-jun

    2005-01-01

    Modulation-doped AlGaAs/GaAs structures were grown on GaAs(100) substrate by solid source molecular beam epitaxy (SSMBE) system. The factors which influence the electron mobility were investigated. After growing InP based materials, growth conditions were deteriorated, but by an appropriate method and using reasonaand growth conditions have been studied and optimized via Hall measurements. For a typical sample, 2.0 K electron served.

  6. Photoluminescence properties of ZnO films grown on InP by thermally oxidizing metallic Zn films

    CERN Document Server

    Chen, S J; Zhang, J Y; Lu, Y M; Shen, D Z; Fan, X W

    2003-01-01

    Photoluminescence (PL) properties of ZnO films grown on (001) InP substrates by thermal oxidization of metallic Zn films, in which oxygen vacancies and interstitial Zn ions are compensated by P ions diffusing from (001) InP substrates, are investigated. X-ray diffraction spectra indicate that P ions have diffused into the Zn films and chemically combined with Zn ions to form Zn sub 3 P sub 2. Intense free exciton emission dominates the PL spectra of ZnO films with very weak deep-level emission. Low-temperature PL spectra at 79 K are dominated by neutral-donor bound exciton emission at 3.299 eV (I sub 4) with a linewidth of 17.3 meV and neutral-acceptor bound exciton emission at 3.264 eV. The free exciton emission increases with increasing temperature and eventually dominates the emission spectrum for temperature higher than 170 K. Furthermore, the visible emission around 2.3 eV correlated with oxygen deficiencies and interstitial Zn defects was quenched to a remarkable degree by P diffusing from InP substrate...

  7. Surface Dipole Formation and Lowering of the Work Function by Cs Adsorption on InP(100) Surface

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.; Liu, Z.; Pianetta, P.

    2007-06-08

    The Cs adsorption on InP(100) surface is studied with Synchrotron Radiation Photoelectron Spectroscopy. The charge transfer from Cs to the InP substrate is observed from the Cs induced In4d and P2p components, and this charge transfer results in surface dipole formation and lowering of the work function. The Cs4d intensity saturates at coverage of one monolayer (ML). However, a break point is observed at 0.5 ML, which coincides with the achievement of the minimum work function. This break point is due to the different vertical placement of the first and the second half monolayer of Cs atoms. Based on this information, a simple bi-layer structure for the Cs layer is presented. This bi-layer structure is consistent with the behavior of the charge transfer from the Cs to the InP substrate at different Cs coverages. This, in turn, explains why the work function decreases to a minimum at 0.5 ML of Cs and remains almost constant beyond this coverage. The depolarization of the surface dipoles is attributed to the saturation of charge transfer to the surface In atoms and the polarization of the Cs atoms in the second half monolayer induced by the positively charged Cs atoms in the first half monolayer.

  8. Surface Dipole Formation and Lowering of the Work Function by Cs Adsorption on InP(100) Surface

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.; Liu, Z.; Pianetta, P.

    2007-06-08

    The Cs adsorption on InP(100) surface is studied with Synchrotron Radiation Photoelectron Spectroscopy. The charge transfer from Cs to the InP substrate is observed from the Cs induced In4d and P2p components, and this charge transfer results in surface dipole formation and lowering of the work function. The Cs4d intensity saturates at coverage of one monolayer (ML). However, a break point is observed at 0.5 ML, which coincides with the achievement of the minimum work function. This break point is due to the different vertical placement of the first and the second half monolayer of Cs atoms. Based on this information, a simple bi-layer structure for the Cs layer is presented. This bi-layer structure is consistent with the behavior of the charge transfer from the Cs to the InP substrate at different Cs coverages. This, in turn, explains why the work function decreases to a minimum at 0.5 ML of Cs and remains almost constant beyond this coverage. The depolarization of the surface dipoles is attributed to the saturation of charge transfer to the surface In atoms and the polarization of the Cs atoms in the second half monolayer induced by the positively charged Cs atoms in the first half monolayer.

  9. Effect of InP Doping on the Phase Transition of Thin GeSbTe Films

    Science.gov (United States)

    Bang, Ki Su; Oh, Yong Jun; Lee, Seung-Yun

    2015-08-01

    We report the crystallization and phase-transition behavior of GeSbTe thin films doped with indium phosphorus (InP). Pure GeSbTe thin films and InP-doped GeSbTe thin films were prepared by use of an rf magnetron sputtering method. After thermal annealing, electrical and optical changes in the thin films were observed. Sheet resistance and reflectance measurements revealed that InP doping suppresses crystallization of GeSbTe. X-ray diffraction analysis confirmed that addition of In and P atoms inhibits the phase transition from face-centered cubic to hexagonal closed-packed. Nucleation of the doped GeSbTe thin films was delayed at an annealing temperature of 100°C; after thermal annealing, neither segregation nor formation of a secondary phase occurred. These results indicate that InP doping improves the amorphous stability of GeSbTe thin films. It is believed this enhanced amorphous stability is a result of the formation of multiple, strong crosslinks by the In and P atoms.

  10. A 311-GHz Fundamental Oscillator Using InP HBT Technology

    Science.gov (United States)

    Gaier, Todd; Fung, King Man; Samoska, Lorene; Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, W.R.

    2010-01-01

    This oscillator uses a single-emitter 0.3- m InP heterojunction bipolar transistor (HBT) device with maximum frequency of oscillation (fmax) greater than 500 GHz. Due to high conductor and substrate losses at submillimeterwave frequencies, a primary challenge is to efficiently use the intrinsic device gain. This was done by using a suitable transmission-line media and circuit topology. The passive components of the oscillator are realized in a twometal process with benzocyclobutene (BCB) used as the primary transmission line dielectric. The circuit was designed using microstrip transmission lines. The oscillator is implemented in a common-base topology due to its inherent instability, and the design includes an on-chip resonator, outputmatching circuitry, and an injection-locking port, the port being used to demonstrate the injection-locking prin ciple. A free-running frequency of 311.6 GHz has been measured by down-converting the signal. Ad di tionally, injection locking has been successfully demonstrated with up to 17.8 dB of injection-locking gain. The injection-locking reference signal is generated using a 2 20 GHz frequency synthesizer, followed by a doubler, active tripler, a W-band amplifier, and then a passive tripler. Therefore, the source frequency is multiplied 18 times to obtain a signal above 300 GHz that can be used to injection lock the oscillator. Measurement shows that injection locking has improved the phase noise of the oscillator and can be also used for synchronizing a series of oscillators. A signal conductor is implemented near the BCP -InP interface and the topside of the BCB layer is fully metallized as a signal ground. Because the fields are primarily constrained in the lower permittivity BCB region, this type of transmission line is referred to as an inverted microstrip. In addition, both common-emitter and commonbase circuits were investigated to determine optimum topology for oscillator design. The common -base topology required smaller

  11. Aerosol measurements during COPE: composition, size, and sources of CCN and INPs at the interface between marine and terrestrial influences

    Science.gov (United States)

    Taylor, Jonathan W.; Choularton, Thomas W.; Blyth, Alan M.; Flynn, Michael J.; Williams, Paul I.; Young, Gillian; Bower, Keith N.; Crosier, Jonathan; Gallagher, Martin W.; Dorsey, James R.; Liu, Zixia; Rosenberg, Philip D.

    2016-09-01

    Heavy rainfall from convective clouds can lead to devastating flash flooding, and observations of aerosols and clouds are required to improve cloud parameterisations used in precipitation forecasts. We present measurements of boundary layer aerosol concentration, size, and composition from a series of research flights performed over the southwest peninsula of the UK during the COnvective Precipitation Experiment (COPE) of summer 2013. We place emphasis on periods of southwesterly winds, which locally are most conducive to convective cloud formation, when marine air from the Atlantic reached the peninsula. Accumulation-mode aerosol mass loadings were typically 2-3 µg m-3 (corrected to standard cubic metres at 1013.25 hPa and 273.15 K), the majority of which was sulfuric acid over the sea, or ammonium sulfate inland, as terrestrial ammonia sources neutralised the aerosol. The cloud condensation nuclei (CCN) concentrations in these conditions were ˜ 150-280 cm-3 at 0.1 % and 400-500 cm-3 at 0.9 % supersaturation (SST), which are in good agreement with previous Atlantic measurements, and the cloud drop concentrations at cloud base ranged from 100 to 500 cm-3. The concentration of CCN at 0.1 % SST was well correlated with non-sea-salt sulfate, meaning marine sulfate formation was likely the main source of CCN. Marine organic aerosol (OA) had a similar mass spectrum to previous measurements of sea spray OA and was poorly correlated with CCN. In one case study that was significantly different to the rest, polluted anthropogenic emissions from the southern and central UK advected to the peninsula, with significant enhancements of OA, ammonium nitrate and sulfate, and black carbon. The CCN concentrations here were around 6 times higher than in the clean cases, and the cloud drop number concentrations were 3-4 times higher. Sources of ice-nucleating particles (INPs) were assessed by comparing different parameterisations used to predict INP concentrations, using measured

  12. Low-temperature damage formation in ion implanted InP

    Energy Technology Data Exchange (ETDEWEB)

    Wendler, E., E-mail: elke.wendler@uni-jena.de [Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena (Germany); Stonert, A. [National Center of Nuclear Research, 05-400 Swierk/Otwock (Poland); Turos, A. [National Center of Nuclear Research, 05-400 Swierk/Otwock (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Wesch, W. [Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena (Germany)

    2013-07-15

    Damage formation in ion implanted InP is studied by quasi–in situ Rutherford backscattering spectrometry (RBS) in channelling configuration. Subsequent implantation steps are performed at 15 K each followed by immediate RBS analysis without changing the environment or the temperature of the sample. 30 keV He, 150 keV N and 350 keV Ca ions were applied. The depth distribution of damage is in good agreement with that calculated with the SRIM code. The evolution of damage at the maximum of the distribution as a function of the ion fluence is described assuming damage formation within single ion impacts and stimulated growth of damage when the collision cascades start to overlap with cross sections σ{sub d} and σ{sub g}, respectively. These cross sections are found to depend on the primary energies deposited in the displacement of lattice atoms and in electronic interactions calculated with the SRIM code. The obtained empirical formulas are capable to represent the experimental results for different III–V compounds implanted at 15 K with various ion species.

  13. Heteroepitaxial InP, and ultrathin, directly glassed, GaAs 3-5 solar cells

    Science.gov (United States)

    Hardingham, C. M.; Cross, T. A.

    1993-01-01

    The commercial application of Indium Phosphide solar cells in practical space missions is crucially dependent upon achieving a major cost reduction which could be offered by heteroepitaxy on cheaper, more rugged substrates. Furthermore, significant mass reduction, compatibility with mechanically stacked multijunction cells, and elimination of the current loss through glue discoloration, is possible in III-V solar cells by the development of ultrathin, directly glassed cells. The progress of a UK collaborative program to develop high efficiency, homojunction InP solar cells, grown by MOCVD on Si substrates, is described. Results of homoepitaxial cells (is greater than 17 percent 1 Sun AM0) are presented, together with progress in achieving low dislocation density heteroepitaxy. Also, progress in a UK program to develop ultrathin directly-glassed GaAs cells is described. Ultrathin (5 micron) GaAs cells, with 1 Sun AM0 efficiencies up to 19.1 percent, are presented, together with progress in achieving a direct (adhesive-less) bond between the cell and coverglass. Consequential development to, for example, cell grids, are also discussed.

  14. An ab initio study of the polytypism in InP

    Science.gov (United States)

    Dacal, Luis C. O.; Cantarero, A.

    2016-09-01

    The existence of polytypism in semiconductor nanostructures gives rise to the appearance of stacking faults which many times can be treated as quantum wells. In some cases, despite of a careful growth, the polytypism can be hardly avoided. In this work, we perform an ab initio study of zincblende stacking faults in a wurtzite InP system, using the supercell approach and taking the limit of low density of narrow stacking faults regions. Our results confirm the type II band alignment between the phases, producing a reliable qualitative description of the band gap evolution along the growth axis. These results show an spacial asymmetry in the zincblende quantum wells, that is expected due to the fact that the wurtzite stacking sequence (ABAB) is part of the zincblende one (ABCABC), but with an unexpected asymmetry between the valence and the conduction bands. We also present results for the complex dielectric function, clearly showing the influence of the stacking on the homostructure values and surprisingly proving that the correspondent bulk results can be used to reproduce the polytypism even in the limit we considered.

  15. Tunable optical filters for in-plane integration on InP MEMS platform

    Science.gov (United States)

    Datta, M.; McGee, J.; Pruessner, M. W.; Amarnath, K.; Kanakaraju, S.; Ghodssi, R.

    2005-07-01

    We have demonstrated a planar waveguide-based tunable integrated optical filter in indium phosphide (InP) with on-chip micro-electro-mechanical (MEMS) actuation. An air-gap Fabry-Perot resonant microcavity is formed between two waveguides, whose facets have monolithically integrated high-reflectivity multilayer InP/air Distributed Bragg Reflector (DBR) mirrors. A suspended beam electrostatic microactuator attached to one of the DBR mirrors modulates the microcavity length, resulting in a tunable filter. The DBR mirrors provide a broad high-reflectivity spectrum, within which the transmission wavelength can be tuned. The in-plane configuration of the filter enables easy integration with other active and passive waveguide-based optoelectronic devices on a chip and simplifies fiber alignment. Experimental results from the first generation of tunable optical filters are presented. The microfabricated filter exhibited a resonant wavelength shift of 12nm (1513-1525nm) at a low operating voltage of 7V. A full-width-half-maximum (FWHM) of 33 nm was experimentally observed, and the quality factor was calculated to be 46. Several improvements of the MEMS actuator, waveguide, and optical cavity design for the future devices are discussed.

  16. Doping evaluation of InP nanowires for tandem junction solar cells

    Science.gov (United States)

    Lindelöw, F.; Heurlin, M.; Otnes, G.; Dagytė, V.; Lindgren, D.; Hultin, O.; Storm, K.; Samuelson, L.; Borgström, M.

    2016-02-01

    In order to push the development of nanowire-based solar cells further using optimized nanowire diameter and pitch, a doping evaluation of the nanowire geometry is necessary. We report on a doping evaluation of n-type InP nanowires with diameters optimized for light absorption, grown by the use of metal-organic vapor phase epitaxy in particle-assisted growth mode using tetraethyltin (TESn) as the dopant precursor. The charge carrier concentration was evaluated using four-probe resistivity measurements and spatially resolved Hall measurements. In order to reach the highest possible nanowire doping level, we set the TESn molar fraction at a high constant value throughout growth and varied the trimethylindium (TMIn) molar fraction for different runs. Analysis shows that the charge carrier concentration in nanowires grown with the highest TMIn molar fraction (not leading to kinking nanowires) results in a low carrier concentration of approximately 1016 cm-3. By decreasing the molar fraction of TMIn, effectively increasing the IV/III ratio, the carrier concentration increases up to a level of about 1019 cm-3, where it seems to saturate. Axial carrier concentration gradients along the nanowires are found, which can be correlated to a combination of changes in the nanowire growth rate, measured in situ by optical reflectometry, and polytypism of the nanowires observed in transmission electron microscopy.

  17. Micromanipulation of InP lasers with optoelectronic tweezers for integration on a photonic platform.

    Science.gov (United States)

    Juvert, Joan; Zhang, Shuailong; Eddie, Iain; Mitchell, Colin J; Reed, Graham T; Wilkinson, James S; Kelly, Anthony; Neale, Steven L

    2016-08-08

    The integration of light sources on a photonic platform is a key aspect of the fabrication of self-contained photonic circuits with a small footprint that does not have a definitive solution yet. Several approaches are being actively researched for this purpose. In this work we propose optoelectronic tweezers for the manipulation and integration of light sources on a photonic platform and report the positional and angular accuracy of the micromanipulation of standard Fabry-Pérot InP semiconductor laser die. These lasers are over three orders of magnitude bigger in volume than any previously assembled with optofluidic techniques and the fact that they are industry standard lasers makes them significantly more useful than previously assembled microdisk lasers. We measure the accuracy to be 2.5 ± 1.4 µm and 1.4 ± 0.4° and conclude that optoelectronic tweezers are a promising technique for the micromanipulation and integration of optoelectronic components in general and semiconductor lasers in particular.

  18. Thermal conductivity of InAs quantum dot stacks using AlAs strain compensating layers on InP substrate

    Energy Technology Data Exchange (ETDEWEB)

    Salman, S. [Universite Europeenne de Bretagne, CNRS, Laboratoire FOTON, INSA, 20 Avenue des buttes de Coeesmes, 35708 Rennes, Cedex 7 (France); Folliot, H., E-mail: herve.folliot@insa-rennes.fr [Universite Europeenne de Bretagne, CNRS, Laboratoire FOTON, INSA, 20 Avenue des buttes de Coeesmes, 35708 Rennes, Cedex 7 (France); Le Pouliquen, J.; Chevalier, N.; Rohel, T.; Paranthoeen, C.; Bertru, N. [Universite Europeenne de Bretagne, CNRS, Laboratoire FOTON, INSA, 20 Avenue des buttes de Coeesmes, 35708 Rennes, Cedex 7 (France); Labbe, C. [CIMAP, CEA/UMR CNRS 6252/ENSICAEN/Universite de Caen Basse Normandie, 6, Boulevard Marechal Juin, 14050 Caen Cedex 4 (France); Letoublon, A.; Le Corre, A. [Universite Europeenne de Bretagne, CNRS, Laboratoire FOTON, INSA, 20 Avenue des buttes de Coeesmes, 35708 Rennes, Cedex 7 (France)

    2012-06-25

    Highlights: Black-Right-Pointing-Pointer The thermal conductivity of InAs on InP (1 1 3)B quantum dots stacks is measured. Black-Right-Pointing-Pointer The growth of a close stack of 100 layers of InAs using AlAs strain compensating layers is presented. Black-Right-Pointing-Pointer New data on the thermal conductivity of InP n-doped susbtrate are given. - Abstract: The growth and thermal conductivity of InAs quantum dot (QD) stacks embedded in GaInAs matrix with AlAs compensating layers deposited on (1 1 3)B InP substrate are presented. The effect of the strain compensating AlAs layer is demonstrated through Atomic Force Microscopy (AFM) and X-ray diffraction structural analysis. The thermal conductivity (2.7 W/m K at 300 K) measured by the 3{omega} method reveals to be clearly reduced in comparison with a bulk InGaAs layer (5 W/m K). In addition, the thermal conductivity measurements of S doped InP substrates and the SiN insulating layer used in the 3{omega} method in the 20-200 Degree-Sign C range are also presented. An empirical law is proposed for the S doped InP substrate, which slightly differs from previously presented results.

  19. A positive feedback loop of p53/miR-19/TP53INP1 modulates pancreatic cancer cell proliferation and apoptosis.

    Science.gov (United States)

    Wang, Xiaofang; Wang, Lei; Mo, Qingjiang; Jia, Ankui; Dong, Yuqian; Wang, Guoqiang

    2016-01-01

    Pancreatic cancer is a common malignancy whose prognosis and treatment of pancreatic cancer is extremely poor, with only 20% of patients reaching two years of survival. Previous findings have shown that the tumor suppressor p53 is involved in the development of various types of cancer, including pancreatic cancer. Additionally, p53 is able to activate TP53INP1 transcription by regulating several phenotypes of cancer cells. Using gain and loss-of-function assays, the aim of the present study was to examine the relationships between miR-19a/b and cancer development as well as potential underlying mechanisms. The results showed that miR-19a/b identified a positive feedback regulation of p53/TP53INP1 axis. Additionally, p53 upregulated the TP53INP1 level in pancreatic cancer cells. However, overexpressed miR-19a/b partially restored the TP53 function in the pancreatic cancer cells while miR-19a/b downregulated TP53INP1 protein by directly targeting 3'UTR of its mRNA at the post-transcriptional level. In addition, the patient tissues identified that the miR-19a/b level in pancreatic cancer tissues was conversely correlated with TP53 and TP53INP1 expression. The results provide evidence for revealing the molecular mechanism involved in the development of pancreatic cancer and may be useful in the identification of new therapeutic targets for pancreatic cancer.

  20. Impact of P/In flux ratio and epilayer thickness on faceting for nanoscale selective area growth of InP by molecular beam epitaxy.

    Science.gov (United States)

    Fahed, M; Desplanque, L; Coinon, C; Troadec, D; Wallart, X

    2015-07-24

    The impact of the P/In flux ratio and the deposited thickness on the faceting of InP nanostructures selectively grown by molecular beam epitaxy (MBE) is reported. Homoepitaxial growth of InP is performed inside 200 nm wide stripe openings oriented either along a [110] or [1-10] azimuth in a 10 nm thick SiO2 film deposited on an InP(001) substrate. When varying the P/In flux ratio, no major shape differences are observed for [1-10]-oriented apertures. On the other hand, the InP nanostructure cross sections strongly evolve for [110]-oriented apertures for which (111)B facets are more prominent and (001) ones shrink for large P/In flux ratio values. These results show that the growth conditions allow tailoring the nanocrystal shape. They are discussed in the framework of the equilibrium crystal shape model using existing theoretical calculations of the surface energies of different low-index InP surfaces as a function of the phosphorus chemical potential, directly related to the P/In ratio. Experimental observations strongly suggest that the relative (111)A surface energy is probably smaller than the calculated value. We also discuss the evolution of the nanostructure shape with the InP-deposited thickness.

  1. High performance etchant for thinning p(+)-InP and its application to p(+)n InP solar cell fabrication

    Science.gov (United States)

    Faur, Maria; Faur, Mircea; Bailey, Sheila; Brinker, David; Goradia, Manju; Weinberg, Irving; Fatemi, Navid

    1991-01-01

    An etchant, namely (o-H3PO4)u: (HNO3)v: (H2O2)t: (H2O)1-(u+v+t) is developed for thinning, after contacting, the p(+) emitter layer of p(+)n InP structures made by thermal diffusion. Varying u, v, and t, reproducible etch rates of 5 to 110 nm/min are obtained. After thinning the 0.6- to 2.5-micron thick p(+) InP layer down to 60-250 nm, specular surfaces are obtained at up to 80 nm/min etch rate. Due to its intrinsic qualities the resisual P-rich oxide after thinning the emitter layer provides surface passivation of p(+) InP surfaces and can also serve as a first-layer AR coating.

  2. Growth of vertical and defect free InP nanowires on SrTiO3(001) substrate and comparison with growth on silicon

    Science.gov (United States)

    Naji, K.; Dumont, H.; Saint-Girons, G.; Penuelas, J.; Patriarche, G.; Hocevar, M.; Zwiller, V.; Gendry, M.

    2012-03-01

    We present a study of the molecular beam epitaxy of InP nanowires (NWs) on (001) oriented SrTiO3 (STO) substrates using vapor liquid solid mechanism and gold-indium as metal catalyst. The growth direction of InP NWs grown on STO(001) is compared with NWs grown on (001) and (111) oriented silicon substrates. Gold-indium dewetting under a flux of indium results in the majority of InP NWs growing vertically from the surface of STO(001). With the growth parameters we have used the NWs have a pure wurtzite structure and are free of stacking faults and cubic segments. The structural quality of the NWs is confirmed by micro-photoluminescence measurements showing a narrow peak linewidth of 6.5 meV.

  3. InP Gunn diodes with a cathode contact injecting hot electrons. Part 1. Interactions between phases in the cathode contacts

    Directory of Open Access Journals (Sweden)

    Boltovets N. S.

    2010-10-01

    Full Text Available The article presents the research on interactions between phases in the Ge–Au, Ge–TiBx and Au–TiBxAu contacts to n–n+–n++-InP, both before and after rapid thermal annealing, and also the output parameters of Gunn diodes based on the InP structure with Au–TiBx–Au–Ge contact metallization in the –40...+60 °С temperature range. It is shown that ohmic contacts to InP layer are formed as a result of diffusion of Ge and Au atoms deep inside the layer. The output parameters of Gunn diodes with Au–TiBx–Au–Ge cathode contacts agree with the data obtained for InP Gunn diodes made with the use of more complicated technology.

  4. Low temperature planar regrowth of semi-insulating InP by low pressure hydride vapour phase epitaxy for device application

    Science.gov (United States)

    Alexandre, F.; Parillaud, O.; Nguyen, D. C.; Azoulay, R.; Quillec, M.; Bouchoule, S.; Le Mestreallan, G.; Juhel, M.; Le Roux, G.; Rao, E. V. K.

    1998-05-01

    The growth of both undoped and iron doped InP on planar as well as non-planar (0 0 1)InP substrates has been explored using low pressure hydride vapour phase epitaxy (LP-HVPE) in the temperature range of 500-620°C. Secondary ion mass spectroscopy (SIMS), X-ray diffraction and photoluminescence measurements have shown no drastic degradation in the crystal quality with decreasing growth temperature. The Fe incorporation in the layers is found to be independent of the substrate temperature ( Ts) and in all experiments semi-insulating InP : Fe layers with resistivities close to 10 9 Ω cm have been obtained. A perfect growth selectivity with no deposition on masked areas and a good planarized regrowth on mesas has been demonstrated even at low Ts.

  5. Thin-Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates

    KAUST Repository

    Zheng, Maxwell

    2015-08-25

    The design and performance of solar cells based on InP grown by the nonepitaxial thin-film vapor-liquid-solid (TF-VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p-doping process for TF-VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open-circuit voltage (VOC) of 692 mV, short-circuit current (JSC) of 26.9 mA cm-2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP. The design and performance of solar cells based on indium phosphide (InP) grown by the nonepitaxial thin-film vapor-liquid-solid growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and an indium tin oxide transparent top electrode. The highest measured open circuit voltage (VOC) under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP.

  6. Growth and anisotropic transport properties of self-assembled InAs nanostructures in InP

    Energy Technology Data Exchange (ETDEWEB)

    Bierwagen, O.

    2007-12-20

    Self-assembled InAs nanostructures in InP, comprising quantum wells, quantum wires, and quantum dots, are studied in terms of their formation and properties. In particular, the structural, optical, and anisotropic transport properties of the nanostructures are investigated. The focus is a comprehending exploration of the anisotropic in-plane transport in large ensembles of laterally coupled InAs nanostructures. The self-assembled Stranski-Krastanov growth of InAs nanostructures is studied by gas-source molecular beam epitaxy on both nominally oriented and vicinal InP(001). Optical polarization of the interband transitions arising from the nanostructure type is demonstrated by photoluminescence and transmission spectroscopy. The experimentally convenient four-contact van der Pauw Hall measurement of rectangularly shaped semiconductors, usually applied to isotropic systems, is extended to yield the anisotropic transport properties. Temperature dependent transport measurements are performed in large ensembles of laterally closely spaced nanostructures. The transport of quantum wire-, quantum dash- and quantum dot containing samples is highly anisotropic with the principal axes of conductivity aligned to the <110> directions. The direction of higher mobility is [ anti 110], which is parallel to the direction of the quantum wires. In extreme cases, the anisotropies exceed 30 for electrons, and 100 for holes. The extreme anisotropy for holes is due to diffusive transport through extended states in the [ anti 110], and hopping transport through laterally localized states in the [110] direction, within the same sample. A novel 5-terminal electronic switching device based on gate-controlled transport anisotropy is proposed. The gate-control of the transport anisotropy in modulation-doped, self-organized InAs quantum wires embedded in InP is demonstrated. (orig.)

  7. Determination of the complex linear electro-optic coefficient of GaAs and InP

    Energy Technology Data Exchange (ETDEWEB)

    Pristovsek, Markus [Technische Universitaet Berlin, Institut fuer Festkoerperphysik, Hardenbergstrasse 36, 10623 Berlin (Germany)

    2010-08-15

    The complex linear electro-optic coefficient d{sub 41} was determined for the first time above the fundamental band gap of GaAs and InP by measuring the doping induced band bending of several oxidized samples in reflectance anisotropy spectroscopy. From the real and imaginary part of the change of the spectra for different carrier concentrations the spectral change of d{sub 41} was calculated. This is the first determination of the imaginary part Im(d{sub 41}). (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  8. First system experiments with a monolithically integrated tunable polarization diversity heterodyne receiver OEIC on InP

    Science.gov (United States)

    Hilbk, U.; Hermes, T.; Meissner, P.; Westphal, F. J.; Jacumeit, G.; Stenzel, R.; Unterboersch, G.

    1995-01-01

    System performance of an integrated polarization diversity heterodyne receiver optoelectronic IC (OEIC) is reported. The OEIC is monolithically integrated on InP. It includes a tunable 4 section DBR laser (quasi continuous tuning range 3.5 nm) and balanced photodiodes. The packaged OEIC is supplied with a fiber pigtail. Stable and polarization independent operation is achieved without any tendency for a bit error floor. The sensitivity at 1550.2 nm is -33.5 dBm at a bitrate of 140 Mbit/s. The performance of the OEIC based receiver is verified by operating in an experimental OFDM-TV distribution system with 4 channels.

  9. Transport phenomena in a high pressure crystal growth system: In situ synthesis for InP melt

    Science.gov (United States)

    Zhang, H.; Prasad, V.; Anselmo, A. P.; Bliss, D. F.; Iseler, G.

    1997-06-01

    The physical phenomena underlying the "one-step" in situ synthesis and high pressure growth of indium phosphide crystals are complex. A high resolution computer model based on multizone adaptive grid generation and curvilinear finite volume discretization is used to predict the flow and temperature fields during the synthesis of the InP melt. Simulations are performed for a range of parameters, including Grashof number, crucible rotation, and location of the injector. These parameters affect the gas flow in a high pressure liquid-encapsulated Czochralski (HPLEC) furnace significantly, and have a strong influence on the melt synthesis and its control.

  10. Kinetics of low pressure CVD growth of SiO2 on InP and Si

    Science.gov (United States)

    Iyer, R.; Lile, D. L.

    1988-01-01

    The kinetics of low pressure CVD growth of SiO2 from SiH4 and O2 has been investigated for the case of an indirect (remote) plasma process. Homogeneous (gas phase) and heterogeneous operating ranges have been experimentally identified. The process was shown to be consistent within the heterogeneous surface-reaction dominated range of operation. A kinetic rate equation is given for growth at 14 W RF power input and 400 mtorr total pressure on both InP and Si substrates. The process exhibits an activation energy of 8.4 + or - 0.6 kcal/mol.

  11. Morphology, luminescence, and electrical resistance response to H 2 and CO gas exposure of porous InP membranes prepared by electrochemistry in a neutral electrolyte

    Science.gov (United States)

    Volciuc, O.; Monaico, E.; Enachi, M.; Ursaki, V. V.; Pavlidis, D.; Popa, V.; Tiginyanu, I. M.

    2010-11-01

    Porous InP membranes have been prepared by anodization of InP wafers with electron concentration of 1 × 10 17 cm -3 and 1 × 10 18 cm -3 in a neutral NaCl electrolyte. The internal surfaces of pores in some membranes were modified by electrochemical deposition of gold in a pulsed voltage regime. Photoluminescence and photosensitivity measurements indicate efficient light trapping and porous surface passivation. The photoluminescence and electrical resistivity of the membranes are sensitive to the adsorption of H 2 and CO gas molecules. These properties are also influenced by the deposition of Au nanoparticles inside the pores.

  12. Morphology, luminescence, and electrical resistance response to H{sub 2} and CO gas exposure of porous InP membranes prepared by electrochemistry in a neutral electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Volciuc, O.; Monaico, E.; Enachi, M. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Ursaki, V.V., E-mail: ursaki@yahoo.com [Institute of Applied Physics, Academy of Sciences of Moldova, Academy str. 5, Chisinau 2028 (Moldova, Republic of); Pavlidis, D. [Fachgebiet fuer Hoechstfrequenzelektronik, Technische Universitaet Darmstadt, Merckstrasse 25, Darmstadt 64283 (Germany); Popa, V. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Fachgebiet fuer Hoechstfrequenzelektronik, Technische Universitaet Darmstadt, Merckstrasse 25, Darmstadt 64283 (Germany); Tiginyanu, I.M. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Academy str. 3/3, Chisinau 2028 (Moldova, Republic of)

    2010-11-15

    Porous InP membranes have been prepared by anodization of InP wafers with electron concentration of 1 x 10{sup 17} cm{sup -3} and 1 x 10{sup 18} cm{sup -3} in a neutral NaCl electrolyte. The internal surfaces of pores in some membranes were modified by electrochemical deposition of gold in a pulsed voltage regime. Photoluminescence and photosensitivity measurements indicate efficient light trapping and porous surface passivation. The photoluminescence and electrical resistivity of the membranes are sensitive to the adsorption of H{sub 2} and CO gas molecules. These properties are also influenced by the deposition of Au nanoparticles inside the pores.

  13. Study of growth properties of InAs islands on patterned InP substrates defined by focused ion beam

    Science.gov (United States)

    Ribeiro-Andrade, R.; Malachias, A.; Miquita, D. R.; Vasconcelos, T. L.; Kawabata, R.; Pires, M. P.; Souza, P. L.; Rodrigues, W. N.

    2017-03-01

    This work describes morphological and crystalline properties of the InAs islands grown on templates created by focused ion beam (FIB) on indium phosphide (InP) substrates. Regular arrangements of shallow holes are created on the InP (001) surfaces, acting as preferential nucleation sites for InAs islands grown by Metal-Organic Vapor Phase Epitaxy. Ion doses ranging from 1015 to 1016 Ga+/cm2 were used and islands were grown for two sub-monolayer coverages. We observe the formation of clusters in the inner surfaces of the FIB produced cavities and show that for low doses templates the nanostructures are mainly coherent while templates created with large ion doses lead to the growth of incoherent islands with larger island density. The modified island growth is described by a simple model based on the surface potential and the net adatom flow to the cavities. We observe that obtained morphologies result from a competition between coarsening and coalescence mechanisms.

  14. Hydrogen Passivation of Interstitial Zn Defects in Heteroepitaxial InP Cell Structures and Influence on Device Characteristics

    Science.gov (United States)

    Ringel, S. A.; Chatterjee, B.

    2004-01-01

    Hydrogen passivation of heteroepitaxial InP solar cells is of recent interest for deactivation of dislocations and other defects caused by the cell/substrate lattice mismatch that currently limit the photovoltaic performance of these devices. In this paper we present strong evidence that, in addition to direct hydrogen-dislocation interactions, hydrogen forms complexes with the high concentration of interstitial Zn defects present within the p(+) Zn-doped emitter of MOCVD-grown heteroepitaxial InP devices, resulting in a dramatic increase of the forward bias turn-on voltage by as much as 280 mV, from 680 mV to 960 mV. This shift is reproducible and thermally reversible and no such effect is observed for either n(+)p structures or homoepitaxial p(+)n structures grown under identical conditions. A combination of photoluminescence (PL), electrochemical C-V dopant profiling, SIMS and I-V measurements were performed on a set of samples having undergone a matrix of hydrogenation and post-hydrogenation annealing conditions to investigate the source of this voltage enhancement and confirm the expected role of interstitial Zn and hydrogen. A precise correlation between all measurements is demonstrated which indicates that Zn interstitials within the p(+) emitter and their interaction with hydrogen are indeed responsible for this device behavior.

  15. Vertical and Smooth, etching of InP by Cl2/CH4/Ar Inductively Coupled Plasma at Room Temperature

    Institute of Scientific and Technical Information of China (English)

    孙长征; 周进波; 熊兵; 王健; 罗毅

    2003-01-01

    We study the room-temperature dry, etching of InP by inductively coupled plasma (ICP) using Cl2/CH4/Ar mixtures. Etches were characterized in terms of anisotropy and surface roughness by scanning electron microscopy and atomic force microscopy, respectively. It is found that the flow ratio between Cl2 and CH4, ICP power, rf chuck power, and table temperature can greatly influence the, etching results. By adjusting, etching parameters,vertical sidewall and smooth surface can be obtained simultaneously, together with a moderate, etch rate and a good select ratio. The root-mean-square surface roughness is measured to be as low as 0.27nm. To the best of our knowledge, this is the best result for InP to date. The, etch rate is 855 nm/min, and the selectivity ratio over SiO2 is estimated to be higher than 15:1. The stoichiometry of the, etched surface has also been investigated by Auger electron spectroscopy. The, etched surface is found to manifest a slight P deficiency, and the ratio between P and In reaches the stoichiometric value within about 0.75nm depth into the surface.

  16. Modulation of electrical properties in Cu/n-type InP Schottky junctions using oxygen plasma treatment

    Science.gov (United States)

    Kim, Hogyoung; Cho, Yunae; Jung, Chan Yeong; Kim, Se Hyun; Kim, Dong-Wook

    2015-12-01

    Using current-voltage (I-V) measurements, we investigated the effect of oxygen plasma treatment on the temperature-dependent electrical properties of Cu/n-type indium phosphide (InP) Schottky contacts at temperatures in the range 100-300 K. Changes in the electrical parameters were evident below 180 K for the low-plasma-power sample (100 W), which is indicative of the presence of a wider distribution of regions of low barrier height. Modified Richardson plots were used to obtain Richardson constants, which were similar to the theoretical value of 9.4 A cm-2 K-2 for n-type InP. This suggests that, for all the samples, a thermionic emission model including a spatially inhomogeneous Schottky barrier can be used to describe the charge transport phenomena at the metal/semiconductor interface. The voltage dependence of the reverse-bias current revealed that Schottky emission was dominant for the untreated and high-plasma-power (250 W) samples. For the low-plasma-power sample, Poole-Frenkel emission was dominant at low voltages, whereas Schottky emission dominated at higher voltages. Defect states and nonuniformity of the interfacial layer appear to be significant in the reverse-bias charge transport properties of the low-plasma-power sample.

  17. Model of a realistic InP surface quantum dot extrapolated from atomic force microscopy results.

    Science.gov (United States)

    Barettin, Daniele; De Angelis, Roberta; Prosposito, Paolo; Auf der Maur, Matthias; Casalboni, Mauro; Pecchia, Alessandro

    2014-05-16

    We report on numerical simulations of a zincblende InP surface quantum dot (QD) on In₀.₄₈Ga₀.₅₂ buffer. Our model is strictly based on experimental structures, since we extrapolated a three-dimensional dot directly by atomic force microscopy results. Continuum electromechanical, [Formula: see text] bandstructure and optical calculations are presented for this realistic structure, together with benchmark calculations for a lens-shape QD with the same radius and height of the extrapolated dot. Interesting similarities and differences are shown by comparing the results obtained with the two different structures, leading to the conclusion that the use of a more realistic structure can provide significant improvements in the modeling of QDs fact, the remarkable splitting for the electron p-like levels of the extrapolated dot seems to prove that a realistic experimental structure can reproduce the right symmetry and a correct splitting usually given by atomistic calculations even within the multiband [Formula: see text] approach. Moreover, the energy levels and the symmetry of the holes are strongly dependent on the shape of the dot. In particular, as far as we know, their wave function symmetries do not seem to resemble to any results previously obtained with simulations of zincblende ideal structures, such as lenses or truncated pyramids. The magnitude of the oscillator strengths is also strongly dependent on the shape of the dot, showing a lower intensity for the extrapolated dot, especially for the transition between the electrons and holes ground state, as a result of a relevant reduction of the wave functions overlap. We also compare an experimental photoluminescence spectrum measured on an homogeneous sample containing about 60 dots with a numerical ensemble average derived from single dot calculations. The broader energy range of the numerical spectrum motivated us to perform further verifications, which have clarified some aspects of the experimental

  18. Longitudinal and transverse exciton-spin relaxation in a single InAsP quantum dot embedded inside a standing InP nanowire using photoluminescence spectroscopy

    NARCIS (Netherlands)

    Sasakura, H.; Hermannstädter, C.; Dorenbos, S.N.; Akopian, N.; Van Kouwen, M.P.; Motohisa, J.; Kobayashi, Y.; Kumano, H.; Kondo, K.; Tomioka, K.; Fukui, T.; Suemune, I.; Zwiller, V.

    2012-01-01

    We have investigated the optical properties of a single InAsP quantum dot embedded in a standing InP nanowire. Elongation of the transverse exciton-spin relaxation time of the exciton state with decreasing excitation power was observed by first-order photon correlation measurements. This behavior is

  19. Growing InGaAs quasi-quantum wires inside semi-rhombic shaped planar InP nanowires on exact (001) silicon

    Science.gov (United States)

    Han, Yu; Li, Qiang; Chang, Shih-Pang; Hsu, Wen-Da; Lau, Kei May

    2016-06-01

    We report InGaAs quasi-quantum wires embedded in planar InP nanowires grown on (001) silicon emitting in the 1550 nm communication band. An array of highly ordered InP nanowire with semi-rhombic cross-section was obtained in pre-defined silicon V-grooves through selective-area hetero-epitaxy. The 8% lattice mismatch between InP and Si was accommodated by an ultra-thin stacking disordered InP/GaAs nucleation layer. X-ray diffraction and transmission electron microscope characterizations suggest excellent crystalline quality of the nanowires. By exploiting the morphological evolution of the InP and a self-limiting growth process in the V-grooves, we grew embedded InGaAs quantum-wells and quasi-quantum-wires with tunable shape and position. Room temperature analysis reveals substantially improved photoluminescence in the quasi-quantum wires as compared to the quantum-well reference, due to the reduced intrusion defects and enhanced quantum confinement. These results show great promise for integration of III-V based long wavelength nanowire lasers on the well-established (001) Si platform.

  20. A physical based equivalent circuit modeling approach for ballasted InP DHBT multi-finger devices at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Midili, Virginio; Squartecchia, Michele; Johansen, Tom Keinicke

    2016-01-01

    Multifinger InP DHBTs can be designed with a ballasting resistor to improve power capability. However accurate modeling is needed to predict high frequency behavior of the device. This paper presents two distinct modeling approaches: one based on EM simulations and one based on a physical equival...

  1. Fe-contacts on InAs(100) and InP(100) characterised by conversion electron Mössbauer spectroscopy

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Gunnlaugsson, H.P; Weyer, G.;

    2005-01-01

    We have grown 4 nm thin films of Fe-57 on InAs(100) and InP(100) surfaces by use of MBE and studied the samples by Fe-57 conversion electron Mossbauer spectroscopy. In the case of InAs, the Mossbauer spectrum showed a sextet due to alpha-Fe and a further magnetically split component with slightly...

  2. Synthesis of Cu-doped InP nanocrystals (d-dots) with ZnSe diffusion barrier as efficient and color-tunable NIR emitters.

    Science.gov (United States)

    Xie, Renguo; Peng, Xiaogang

    2009-08-05

    Efficient Cu-doped InP quantum dots (Cu:InP d-dots) emitters were successfully synthesized by epitaxial growth of a ZnSe diffusion barrier for the dopants. The Cu dopant emission of the Cu:InP/ZnSe core/shell d-dots covered the important red and near-infrared (NIR) window for biomedical applicaitons, from 630 to 1100 nm, by varying the size of the InP host nanocrystals. These new d-dots emitters not only compensate for the emission wavelength of the existing noncadmium d-dots emitters, Cu- and Mn-doped ZnSe d-dots (450-610 nm), but also offer a complete series of efficient nanocrystal emitters based on InP nanocrystals. The one-pot synthetic scheme for the formation of Cu:InP/ZnSe core/shell d-dots was successfully established by systematically studying the doping process, the dopant concentration-dependent photophysical properties, and the dopant diffusion during shell epitaxy, etc. Complete elimination of InP bandgap emission and efficient pure dopant emission (with photoluminescence quantum yield as high as between 35-40%) of the core/shell d-dots were achieved by optimizing the final doping level and the diffusion barrier thickness.

  3. Photoreflectance and DLTS evaluation of plasma-induced damage in GaAs and InP prior to solar cell fabrication

    Science.gov (United States)

    He, L.; Anderson, W. A.

    1991-01-01

    The effect is considered of plasma etching on both GaAs and InP followed by damage removal using rapid thermal annealing (RTA). Effects of these processes were studied by photoreflectance spectroscopy (PR) and deep level transient spectroscopy (DLTS). These techniques are useful in evaluation of wafers prior to and effects of plasma processing during solar cell fabrication.

  4. Exploring the effective photon management by InP nanoparticles: Broadband light absorption enhancement of InP/In{sub 0.53}Ga{sub 0.47}As/InP thin-film photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Dong; Zhu, Xi; Li, Jian; Xu, Yun; Song, Guofeng; Wei, Xin, E-mail: weix@red.semi.ac.cn [Nano-optoelectronics Laboratory, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Liu, Jietao [School of Physics and Optoelectronic Engineering, Xidian University, Xi' an, Shannxi 710071 (China)

    2015-05-28

    High-index dielectric and semiconductor nanoparticles with the characteristics of low absorption loss and strong scattering have attracted more and more attention for improving performance of thin-film photovoltaic devices. In this paper, we focus our attention on InP nanoparticles and study the influence of the substrate and the geometrical configurations on their scattering properties. We demonstrate that, compared with the InP sphere, the InP cylinder has higher coupling efficiency due to the stronger interactions between the optical mode in the nanoparticle and its induced mirror image in the substrate. Moreover, we propose novel thin-film InGaAs photodetectors integrated with the periodically arranged InP nanoparticles on the substrate. Broadband light absorption enhancement is achieved over the wavelength range between 1.0 μm and 1.7 μm. The highest average absorption enhancement of 59.7% is realized for the photodetector with the optimized cylinder InP nanoparticles. These outstanding characteristics attribute to the preferentially forward scattering of single InP nanoparticle along with the effective coupling of incident light into the guided modes through the collective diffraction effect of InP nanoparticles array.

  5. Ten-Fold Enhancement of InAs Nanowire Photoluminescence Emission with an InP Passivation Layer.

    Science.gov (United States)

    Jurczak, Pamela; Zhang, Yunyan; Wu, Jiang; Sanchez, Ana M; Aagesen, Martin; Liu, Huiyun

    2017-06-14

    In this Letter, we demonstrate that a significant improvement of optical performance of InAs nanowires can be achieved by capping the core InAs nanowires with a thin InP shell, which successfully passivates the surface states reducing the rate of nonradiative recombination. The improvements have been confirmed by detailed photoluminescence measurements, which showed up to a 10-fold increase in the intensity of room-temperature photoluminescence from the capped InAs/InP nanowires compared to the sample with core-only InAs nanowires. Moreover, the nanowires exhibit a high stability of total photoluminescence emission strength across temperature range from 10 to 300 K as a result of strong quantum confinement. These findings could be the key to successful implementation of InAs nanowires into optoelectronic devices.

  6. Atomistic comparative study of VUV photodeposited silicon nitride on InP(100) by simulation and atomic force microscopy

    Science.gov (United States)

    Flicstein, J.; Guillonneau, E.; Marquez, J.; How Kee Chun, L. S.; Maisonneuve, D.; David, C.; Wang, Zh.; Palmier, J. F.; Courant, J. L.

    2000-02-01

    We report on an accurate validation of a new Monte Carlo three-dimensional model. Simulations up to 1200 Å layer thickness have been carried out for amorphous thin film layers of SiN:H deposited at low temperature (400-650 K) on (100) InP, by vacuum ultraviolet (VUV, ˜185 nm)-induced chemical vapor deposition (CVD). The computer simulations in the mesoscopic-submicronic range are compared with atomic force microscopy and index of refraction measurements. The reconstituted surface roughness and the voids discrete representations of the bulk are found to be in good agreement with these measurements. Simultaneously at around 450 K (at ˜175°C), thermal characteristic evolution of the both surface roughness and bulk porosity showed a transition from rough to smooth deposition and from low to high density.

  7. Design of MEMS-tunable novel monolithic optical filters in InP with horizontal bragg mirrors

    Science.gov (United States)

    Datta, Madhumita; Pruessner, Marcel W.; Kelly, Daniel P.; Ghodssi, Reza

    2004-11-01

    This paper presents the theoretical design and analysis of a tunable Fabry-Perot resonant microcavity filter realized by movable-waveguide-based integrated optical MEMS technology in InP. Wide-bandwidth, high-reflectivity horizontal InP/air-gap distributed bragg reflector (DBR) mirrors monolithically integrated with the waveguides have been proposed. The filter can be tuned by moving one of the high-reflectivity mirrors axially with on-chip MEMS electrostatic actuation. Spectral performance of the filter is numerically simulated taking into account the diffraction effects. Finite element mechanical modeling of the parallel-plate capacitive microactuator, consisting of a micromachined suspension beam and fixed electrodes, predicts a wide wavelength tuning range (1250-1650 nm) achievable by low actuation voltage (<7 V).

  8. Growth of anodic films on compound semiconductor electrodes: InP in aqueous (NH sub 4) sub 2 S

    CERN Document Server

    Buckley, D N

    2002-01-01

    Film formation on compound semiconductors under anodic conditions is discussed. The surface properties of InP electrodes were examined following anodization in a (NH sub 4) sub 2 S electrolyte. The observation of a current peak in the cyclic voltammetric curve was attributed to selective etching of the substrate and a film formation process. AFM images of samples anodized in the sulfide solution revealed surface pitting. Thicker films formed at higher potentials exhibited extensive cracking as observed by optical and electron microscopy, and this was explicitly demonstrated to occur ex situ rather than during the electrochemical treatment. The composition of the thick film was identified as In sub 2 S sub 3 by EDX and XPS. The measured film thickness varies linearly with the charge passed, and comparison between experimental thickness measurements and theoretical estimates for the thickness indicate a porosity of over 70 %. Cracking is attributed to shrinkage during drying of the highly porous film and does n...

  9. Fullerene-assisted electron-beam lithography for pattern improvement and loss reduction in InP membrane waveguide devices.

    Science.gov (United States)

    Jiao, Yuqing; Pello, Josselin; Mejia, Alonso Millan; Shen, Longfei; Smalbrugge, Barry; Geluk, Erik Jan; Smit, Meint; van der Tol, Jos

    2014-03-15

    In this Letter, we present a method to prepare a mixed electron-beam resist composed of a positive resist (ZEP520A) and C60 fullerene. The addition of C60 to the ZEP resist changes the material properties under electron beam exposure significantly. An improvement in the thermal resistance of the mixed material has been demonstrated by fabricating multimode interference couplers and coupling regions of microring resonators. The fabrication of distributed Bragg reflector structures has shown improvement in terms of pattern definition accuracy with respect to the same structures fabricated with normal ZEP resist. Straight InP membrane waveguides with different lengths have been fabricated using this mixed resist. A decrease of the propagation loss from 6.6 to 3.3  dB/cm has been demonstrated.

  10. High-power InP quantum dot based semiconductor disk laser exceeding 1.3 W

    Science.gov (United States)

    Schwarzbäck, T.; Bek, R.; Hargart, F.; Kessler, C. A.; Kahle, H.; Koroknay, E.; Jetter, M.; Michler, P.

    2013-03-01

    We demonstrate an optically pumped semiconductor disk laser (OP-SDL) using InP quantum dots (QDs) as active material fabricated by metal-organic vapor-phase epitaxy. The QDs are grown within [(Al0.1Ga0.9)0.52In0.48]0.5P0.5 (abbr. Al0.1GaInP) barriers in order to achieve an emission wavelength around 655 nm. We present optical investigations of the active region showing typical QD behavior like blue shift with increasing excitation power and single emission lines, which show anti-bunching in an intensity auto-correlation measurement. We report maximum output powers of the OP-SDL of 1.39 W at low emission wavelength of ˜654 nm with a slope efficiency of ηdiff=25.4 %.

  11. Strong mode coupling in InP quantum dot-based GaInP microdisk cavity dimers

    Science.gov (United States)

    Witzany, M.; Liu, T.-L.; Shim, J.-B.; Hargart, F.; Koroknay, E.; Schulz, W.-M.; Jetter, M.; Hu, E.; Wiersig, J.; Michler, P.

    2013-01-01

    We report on strong mode coupling in closely spaced GaInP microdisk dimer structures including InP quantum dots as the active medium. Using electron beam lithography and a combination of dry- and wet-etch processes, dimers with inter-disk separations down to d < 100 nm have been fabricated. Applying a photo-thermal heating scheme, we overcome the spectral mode detuning due to the size mismatch between the two disks forming the dimer. We observe signatures of mode coupling in the corresponding photoluminescence spectra with coupling energies of up to 0.66 MeV. With the aid of a numerical analysis, we specify the geometrical and physical factors of the microdisk dimer precisely, and reproduce its spectrum with good agreement.

  12. A Physics-Based Charge-Control Model for InP DHBT Including Current-Blocking Effect

    Institute of Scientific and Technical Information of China (English)

    GE Ji; JIN Zhi; SU Yong-Bo; CHENG Wei; WANG Xian-Wai; CHEN Gao-Peng; LIU Xin-Yu

    2009-01-01

    We develop a physics-based charge-control InP double heterojunction bipolar transistor model including three important effects: current blocking, mobile-charge modulation of the base-collector capacitance and velocity-field modulation in the transit time. The bias-dependent base-collector depletion charge is obtained analytically, which takes into account the mobile-charge modulation. Then, a measurement based voltage-dependent transit time formulation is implemented. As a result, over a wide range of biases, the developed model shows good agreement between the modeled and measured S-parameters and cutoff frequency. Also, the model considering current blocking effect demonstrates more accurate prediction of the output characteristics than conventional vertical bipolar inter company results.

  13. C-band fundamental/first-order mode converter based on multimode interference coupler on InP substrate

    Science.gov (United States)

    Limeng, Zhang; Dan, Lu; Zhaosong, Li; Biwei, Pan; Lingjuan, Zhao

    2016-12-01

    The design, fabrication and characterization of a fundamental/first-order mode converter based on multimode interference coupler on InP substrate were reported. Detailed optimization of the device parameters were investigated using 3D beam propagation method. In the experiments, the fabricated mode converter realized mode conversion from the fundamental mode to the first-order mode in the wavelength range of 1530-1565 nm with excess loss less than 3 dB. Moreover, LP01 and LP11 fiber modes were successfully excited from a few-mode fiber by using the device. This InP-based mode converter can be a possible candidate for integrated transceivers for future mode-division multiplexing system. Project supported by the National Basic Research Program of China (No. 2014CB340102) and in part by the National Natural Science Foundation of China (Nos. 61274045, 61335009).

  14. Monolithic InP strictly non-blocking 8×8 switch for high-speed WDM optical interconnection.

    Science.gov (United States)

    Kwack, Myung-Joon; Tanemura, Takuo; Higo, Akio; Nakano, Yoshiaki

    2012-12-17

    A strictly non-blocking 8 × 8 switch for high-speed WDM optical interconnection is realized on InP by using the phased-array scheme for the first time. The matrix switch architecture consists of over 200 functional devices such as star couplers, phase-shifters and so on without any waveguide cross-section. We demonstrate ultra-broad optical bandwidth covering the entire C-band through several Input/Output ports combination with extinction ratio performance of more than 20dB. Also, nanoseconds reconfiguration time was successfully achieved by dynamic switching experiment. Error-free transmission was verified for 40-Gbps (10-Gbps × 4ch) WDM signal.

  15. Modelling of OPNMR phenomena using photon energy-dependent in GaAs and InP

    Science.gov (United States)

    Wheeler, Dustin D.; Willmering, Matthew M.; Sesti, Erika L.; Pan, Xingyuan; Saha, Dipta; Stanton, Christopher J.; Hayes, Sophia E.

    2016-12-01

    We have modified the model for optically-pumped NMR (OPNMR) to incorporate a revised expression for the expectation value of the z-projection of the electron spin, and apply this model to both bulk GaAs and a new material, InP. This expression includes the photon energy dependence of the electron polarization when optically pumping direct-gap semiconductors in excess of the bandgap energy, Eg . Rather than using a fixed value arising from coefficients (the matrix elements) for the optical transitions at the k = 0 bandedge, we define a new parameter, Sopt (Eph) . Incorporating this revised element into the expression for , we have simulated the photon energy dependence of the OPNMR signals from bulk semi-insulating GaAs and semi-insulating InP. In earlier work, we matched calculations of electron spin polarization (alone) to features in a plot of OPNMR signal intensity versus photon energy for optical pumping (Ramaswamy et al., 2010). By incorporating an electron spin polarization which varies with pump wavelength into the penetration depth model of OPNMR signal, we are able to model features in both III-V semiconductors. The agreement between the OPNMR data and the corresponding model demonstrates that fluctuations in the OPNMR intensity have particular sensitivity to light hole-to-conduction band transitions in bulk systems. We provide detailed plots of the theoretical predictions for optical pumping transition probabilities with circularly-polarized light for both helicities of light, broken down into illustrative plots of optical magnetoabsorption and spin polarization, shown separately for heavy-hole and light-hole transitions. These plots serve as an effective roadmap of transitions, which are helpful to other researchers investigating optical pumping effects.

  16. Adding GaAs Monolayers to InAs Quantum-Dot Lasers on (001) InP

    Science.gov (United States)

    Qiu, Yueming; Chacon, Rebecca; Uhl, David; Yang, Rui

    2005-01-01

    In a modification of the basic configuration of InAs quantum-dot semiconductor lasers on (001)lnP substrate, a thin layer (typically 1 to 2 monolayer thick) of GaAs is incorporated into the active region. This modification enhances laser performance: In particular, whereas it has been necessary to cool the unmodified devices to temperatures of about 80 K in order to obtain lasing at long wavelengths, the modified devices can lase at wavelengths of about 1.7 microns or more near room temperature. InAs quantum dots self-assemble, as a consequence of the lattice mismatch, during epitaxial deposition of InAs on ln0.53Ga0.47As/lnP. In the unmodified devices, the quantum dots as thus formed are typically nonuniform in size. Strainenergy relaxation in very large quantum dots can lead to poor laser performance, especially at wavelengths near 2 microns, for which large quantum dots are needed. In the modified devices, the thin layers of GaAs added to the active regions constitute potential-energy barriers that electrons can only penetrate by quantum tunneling and thus reduce the hot carrier effects. Also, the insertion of thin GaAs layer is shown to reduce the degree of nonuniformity of sizes of the quantum dots. In the fabrication of a batch of modified InAs quantum-dot lasers, the thin additional layer of GaAs is deposited as an interfacial layer in an InGaAs quantum well on (001) InP substrate. The device as described thus far is sandwiched between InGaAsPy waveguide layers, then further sandwiched between InP cladding layers, then further sandwiched between heavily Zn-doped (p-type) InGaAs contact layer.

  17. Closed-ampoule diffusion of sulfur into Cd-doped InP substrates - Dependence of S profiles on diffusion temperature and time

    Science.gov (United States)

    Faur, Mircea; Faur, Maria; Honecy, Frank; Goradia, Chandra; Goradia, Manju; Jayne, Douglas; Clark, Ralph

    1992-01-01

    In order to optimize the fabrication of n(+)-p InP solar cells made by closed-ampoule diffusion of sulfur into p-InP:Cd substrates, we have investigated the influence of diffusion conditions on sulfur diffusion profiles. We show that S diffusion in InP is dominated by the P vacancy mechanism and is not characterized by a complementary error function as expected for an infinite source diffusion. The S diffusion mechanism in p-InP is qualitatively explained by examining the depth profiles of S, P, and In in the emitter layer and by taking into account the presence and composition of different compounds found to form in the In-P-S-O-Cd system as a result of diffusion.

  18. Multiple-Scattering of Near-Edge x-ray Absorption Fine Structure of Sulphur-Passivated InP(100) Surface

    Institute of Scientific and Technical Information of China (English)

    曹松; 唐景昌; 沈少来; 陈更生; 马丹

    2003-01-01

    We use the multiple-scattering cluster method to calculate the sulphur 1s near-edge x-ray absorption fine structure (NEXAFS) of S-passivated InP(100) surface. The physical origins of the resonances in the NEXAFS have been unveiled. It is shown that the most important resonance is attributed to the photoelectron scattering between the central sulphur and the nearest indium atoms. The studies show that two S-S dimers with the bond lengths of 2.05 A and 3.05 A coexist in the surface, meanwhile the bridge and antibridge site adsorption of single S could not be ruled out. We support the scanning tunnelling microscopy result that the S-passivated InP(100) surface exhibits significant disorder.

  19. Native-oxide-based selective area growth of InP nanowires via metal-organic molecular beam epitaxy mediated by surface diffusion.

    Science.gov (United States)

    Calahorra, Yonatan; Greenberg, Yaakov; Cohen, Shimon; Ritter, Dan

    2012-06-22

    The growth of InP nanowires on an InP(111) B substrate is reported. The substrate native oxide was not removed from the surface prior to growth. Nanowires were grown at 400 °C from gold catalysts in a selective area manner, without bulk growth. Unlike SiO(2)-based metal-organic molecular beam epitaxy selective area growth, the growth reported here is mediated by surface diffusion with a characteristic diffusion length of 4 μm, about an order of magnitude larger than values for diffusion on bare substrates. A pre-growth heating treatment at 450 °C was found to increase the yield of nanowire nucleation from the gold catalysts.

  20. Photoluminescence and photocurrent from InP nanowires with InAsP quantum dots grown on Si by molecular beam epitaxy.

    Science.gov (United States)

    Kuyanov, P; LaPierre, R R

    2015-08-07

    InP nanowires with InAsP quantum dots (QDs) were grown by molecular beam epitaxy on a Si (111) substrates. The structure of the InAsP QDs were studied using transmission electron microscopy, allowing the development of a model where QD growth occurs by group V desorption from the surrounding substrate surface. Micro-photoluminescence was performed at 10 K showing emission at 1.47-1.49 eV from the InP wurtzite structure, and various emission peaks between 0.93 and 1.33 eV attributed to the QDs. The emission was tuned by the QD composition. The effectiveness of an AlInP passivation shell was demonstrated via an improvement in the photoluminescence intensity. Spectrally-resolved photocurrent measurements at room temperature demonstrated infrared response due to absorption within the QDs. The absorption red-shifted with increasing As composition of the QD.

  1. Ab initio calculations of polarization, piezoelectric constants, and elastic constants of InAs and InP in the wurtzite phase

    Energy Technology Data Exchange (ETDEWEB)

    Hajlaoui, C., E-mail: hajlaouic@yahoo.fr; Pedesseau, L. [Université Européenne de Bretagne (France); Raouafi, F.; Ben Cheikh Larbi, F. [Université de Carthage, Laboratoire de Physico-Chimie, des Microstructures et des Microsystémes, Institut Préparatoire aux Études Scientifiques et Techniques (Tunisia); Even, J.; Jancu, J.-M. [Université Européenne de Bretagne (France)

    2015-08-15

    We report first-principle density functional calculations of the spontaneous polarization, piezoelectric stress constants, and elastic constants for the III–V wurtzite structure semiconductors InAs and InP. Using the density functional theory implemented in the VASP code, we obtain polarization values–0.011 and–0.013 C/m{sup 2}, and piezoelectric constants e{sub 33} (e{sub 31}) equal to 0.091 (–0.026) and 0.012 (–0.081) C/m{sup 2} for structurally relaxed InP and InAs respectively. These values are consistently smaller than those of nitrides. Therefore, we predict a smaller built-in electric field in such structures.

  2. Type-II InP quantum dots in wide-bandgap InGaP host for intermediate-band solar cells

    Science.gov (United States)

    Tayagaki, Takeshi; Sugaya, Takeyoshi

    2016-04-01

    We demonstrate type-II quantum dots (QDs) with long carrier lifetimes in a wide-bandgap host as a promising candidate for intermediate-band solar cells. Type-II InP QDs are fabricated in a wide-bandgap InGaP host using molecular beam epitaxy. Time-resolved photoluminescence measurements reveal an extremely long carrier lifetime (i.e., greater than 30 ns). In addition, from temperature-dependent PL spectra, we find that the type-II InP QDs form a negligible valence band offset and conduction band offset of ΔEc ≈ 0.35 eV in the InGaP host. Such a type-II confinement potential for InP/InGaP QDs has a significant advantage for realizing efficient two-step photon absorption and suppressed carrier capture in QDs via Auger relaxation.

  3. Stability Test of White LED with Bilayer Structure of Red InP Quantum Dots and Yellow YAG:Ce3+ Phosphor.

    Science.gov (United States)

    Park, Kwangwon; Deressa, Gemechu; Kim, Daehan; Kim, Jongsu; Kim, Jihoon; Kim, Taehoon

    2016-02-01

    The white-light-emitting diode (white LED), based on the bilayer structure of red InP quantum dots (QDs) with 610 nm peak, and yellow YAG:Ce3+ phosphor with 550 nm peak, were fabricated through a conventional 5050 type LED fabrication process. The white LED exhibited high luminous efficiency of >130 Im/W and high color rendering index of >80 under operating current of 60 mA and color temperature of 5800 K. As an increase of QDs concentrations, the white LED showed higher color rendering index along with lower luminous efficiency, and the energy loss in the reabsorption process between yellow YAG:Ce3+ emission and red QD absorption was observed. As the temperature increases, the x-color coordinates were significantly changed, indicating that the InP QDs still have lower thermal stability. Also our white LED showed about 50% lumen maintenance after 45,000 hours of normal operation.

  4. Prediction of phonon thermal transport in thin GaAs, InAs and InP nanowires by molecular dynamics simulations: influence of the interatomic potential.

    Science.gov (United States)

    Carrete, J; Longo, R C; Gallego, L J

    2011-05-06

    A number of different potentials are currently being used in molecular dynamics simulations of semiconductor nanostructures. Confusion can arise if an inappropriate potential is used. To illustrate this point, we performed direct molecular dynamics simulations to predict the room temperature lattice thermal conductivity λ of thin GaAs, InAs and InP nanowires. In each case, simulations performed using the classical Harrison potential afforded values of λ about an order of magnitude smaller than those obtained using more elaborate potentials (an Abell-Tersoff, as parameterized by Hammerschmidt et al for GaAs and InAs, and a potential of Vashishta type for InP). These results will be a warning to those wishing to use computer simulations to orient the development of quasi-one-dimensional systems as heat sinks or thermoelectric devices.

  5. Prediction of phonon thermal transport in thin GaAs, InAs and InP nanowires by molecular dynamics simulations: influence of the interatomic potential

    Energy Technology Data Exchange (ETDEWEB)

    Carrete, J; Longo, R C; Gallego, L J, E-mail: jesus.carrete@usc.es [Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2011-05-06

    A number of different potentials are currently being used in molecular dynamics simulations of semiconductor nanostructures. Confusion can arise if an inappropriate potential is used. To illustrate this point, we performed direct molecular dynamics simulations to predict the room temperature lattice thermal conductivity {lambda} of thin GaAs, InAs and InP nanowires. In each case, simulations performed using the classical Harrison potential afforded values of {lambda} about an order of magnitude smaller than those obtained using more elaborate potentials (an Abell-Tersoff, as parameterized by Hammerschmidt et al for GaAs and InAs, and a potential of Vashishta type for InP). These results will be a warning to those wishing to use computer simulations to orient the development of quasi-one-dimensional systems as heat sinks or thermoelectric devices.

  6. The simulation of localized surface plasmon and surface plasmon polariton in wire grid polarizer integrated on InP substrate for InGaAs sensor

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2015-07-01

    Full Text Available We numerically demonstrate the integration of gold wire grid polarizer on InP substrate for InGaAs polarimetric imaging. The effective spectral range of wire grid polarizer has been designed in 0.8-3 μm according to InGaAs response waveband. The dips in TM transmission are observed due to surface plasmon (SPs significantly damaging polarization performance. To further understand the coupling mechanism between gold wire grid grating and InP, the different contributions of surface plasmon polariton (SPP and localized surface plasmon (LSP to the dips are analyzed. Both transmission and reflectance spectra are simulated at different grating periods and duty cycles by finite-different time-domain (FDTD method. LSP wavelength is located at around 1 μm and sensitive to the specific shape of metal wire. SPP presents higher resonance wavelength closely related to grating period. The simulations of electric field distribution show the same results.

  7. The role of strain-driven in migration in the growth of self-assembled InAs quantum dots on InP

    CERN Document Server

    Yoon, S H; Lee, T W; Hwang, H D; Yoon, E J; Kim, Y D

    1999-01-01

    Self-assembled InAs quantum dots (SAQDs) were grown on InP by metalorganic chemical vapor deposition. The amount of excess InAs and the aspect ratio of the SAQD increased with temperature and V/III ratio. It is explained that the As/P exchange reaction at the surface played an important role in the kinetics of SAQD formation. Insertion of a lattice-matched InGaAs buffer layer suppressed the excess InAs formation, and lowered the aspect ratio. Moreover, the dots formed on InGaAs buffer layers were faceted, whereas those on InP were hemispherical, confirming the effect of the As/P exchange reaction. The shape of InAs quantum dots on InGaAs buffer layers was a truncated pyramid with four [136] facets and base edges parallel to directions.

  8. First-Principles Study of Structural, Electronic, Mechanical, Thermal, and Phonon Properties of III-Phosphides (BP, AlP, GaP, and InP)

    Science.gov (United States)

    Ehsanfar, S.; Kanjouri, F.; Tashakori, H.; Esmailian, A.

    2017-10-01

    Based on first-principles calculations with generalized gradient approximation as exchange-correlation functional, the structural, electronic, mechanical, thermal, and phonon properties of III-phosphide binary compounds, namely BP, AlP, GaP, and InP, with cubic zincblende structure have been investigated. The calculations were performed in the framework of density functional theory and density functional perturbation theory (DFPT) implemented in the Quantum ESPRESSO package. The results obtained for the structural and electronic properties are in good agreement with available theoretical and experimental results. The results of our electronic calculations indicate semiconducting properties for these binary compounds. Furthermore, the frequency bandgaps and phonon density of states were also investigated. The computed mechanical constants predict that BP, AlP, GaP, and InP are elastically stable. Finally, we determined the heat capacity and entropy for these binary compounds within a quasiharmonic Debye model using DFPT for comparison.

  9. FFT-impedance spectroscopy analysis of the growth of magnetic metal nanowires in ultra-high aspect ratio InP membranes

    Science.gov (United States)

    Gerngross, M.-D.; Carstensen, J.; Föll, H.; Adelung, R.

    2016-01-01

    This paper reports on the characterization of the electrochemical growth process of magnetic nanowires in ultra-high-aspect ratio InP membranes via in situ fast Fourier transform impedance spectroscopy in a typical frequency range from 75 Hz to 18.5 kHz. The measured impedance data from the Ni, Co, and FeCo can be very well fitted using the same electric equivalent circuit consisting of a series resistance in serial connection to an RC-element and a Maxwell element. The impedance data clearly indicate the similarities in the growth behavior of Ni, Co and FeCo nanowires in ultra-high aspect ratio InP membranes—the beneficial impact of boric acid on the metal deposition in ultra-high aspect ratio membranes and the diffusion limitation of boric acid, as well as differences such as passivation or side reactions.

  10. The infuence of different interfaces on electrical and optical characteristics of Te doped ALGaAsSB/ALAsSB Bragg Mirrors on InP

    Directory of Open Access Journals (Sweden)

    Jean C Harmand

    2008-08-01

    Full Text Available The electrical and optical properties of non-doped and Te doped 6.5 periods AlGaAsSb/AlAsSb Bragg mirrors on InP grown by MBE with different types of interfaces between ternary and quaternary layers are reported. The techniques employed were photoluminescence, refectivity and IxV measurements. The digital alloy gradient interface seems to be the best alternative to optimize conduction without significant refectivity losses.

  11. Fabrication of high-aspect-ratio double-slot photonic crystal waveguide in InP heterostructure by inductively coupled plasma etching using ultra-low pressure

    Directory of Open Access Journals (Sweden)

    Kaiyu Cui

    2013-02-01

    Full Text Available Double-slot photonic crystal waveguide (PCW in InP heterostructure is fabricated by inductively coupled plasma (ICP etching. Due to using an ultra-low pressure of 0.05 Pa, etch depths up to 3.5 μm for holes with diameter of 200 nm and 1.8 μm for slots of ∼40 nm are achieved, which indicate a record-high aspect-ratio, i.e. 45, for such narrow slots in InP heterostructure. Moreover, etching quality is evaluated based on both the transmission performance and the linewidth of micro-photoluminescence (μ-PL. In our measurement, a structure-dependent transmission-dip about 17 dB is obtained from a 17-μm-long W3 PCW, and a PL widening as small as 19 nm compared to the corresponding wafer is observed. These promising experimental results evidence the high etching quality realized in this work and confirm the feasibility of etching small-feature-size patterns by ICP technology for InP based devices in future mono-/hetero-integrated photonic circuits.

  12. Development of InP solid state detector and liquid scintillator containing metal complex for measurement of pp/7Be solar neutrinos and neutrinoless double beta decay

    Science.gov (United States)

    Fukuda, Yoshiyuki; Moriyama, Shigetaka

    2012-07-01

    A large volume solid state detector using a semi-insulating Indium Phosphide (InP) wafer have been developed for measurement of pp/7Be solar neutrinos. Basic performance such as the charge collection efficiency and the energy resolution were measured by 60% and 20%, respectively. In order to detect two gammas (115keV and 497keV) from neutrino capture, we have designed hybrid detector which consist InP detector and liquid xenon scintillator for IPNOS experiment. New InP detector with thin electrode (Cr 50Å- Au 50Å). For another possibility, an organic liquid scintillator containing indium complex and zirconium complex were studied for a measurement of low energy solar neutrinos and neutrinosless double beta decay, respectively. Benzonitrile was chosen as a solvent because of good solubility for the quinolinolato complexes (2 wt%) and of good light yield for the scintillation induced by gamma-ray irradiation. The photo-luminescence emission spectra of InQ3 and ZrQ4 in benzonitrile was measured and liquid scintillator cocktail using InQ3 and ZrQ4 (50mg) in benzonitrile solutions (20 mL) with secondary scintillators with PPO (100mg) and POPOP (10mg) was made. The energy spectra of incident gammas were measured, and they are first results of the gamma-ray energy spectra using luminescent of metal complexes.

  13. STUDIES ON OPTICAL MODULATION OF III-V GaN AND InP BASED DDR IMPATT DIODE AT SUB-MILLIMETER WAVE FREQUENCY

    Directory of Open Access Journals (Sweden)

    Soumen Banerjee,

    2010-07-01

    Full Text Available The effect of optically illumination of III-V compound semiconductor Indium Phosphide (InP and Wurtzite phase of Gallium Nitride (Wz-GaN or -GaN based Double Drift Impatt diodes at 300 GHz (0.3 THz has been investigated. The composition of photocurrent is altered by shining light on the p+ side and n+ side of the device through optical windows; thereby giving rise to Top Mounted (TM and Flip Chip (FC structures. The current multiplication factors for lectrons (Mn and for holes (Mp are altered to study the effect of leakage current in controlling the dynamic properties of the device. The conversion efficiency and output power of -GaN Impatt at 0.3 THz are 15.47% and 6.23 W respectively at an optimum bias current density of 0.5 x 108 A/m2 while the same parameters for InP Impatt are 18.38% and 2.81 W respectively at an optimum bias current density of 8.0 x 108 A/m2. Under optical illumination of the device, the frequency shift is observed to be more upwards upon lowering of Mpthan lowering of Mn. The frequency chirping in InP and -GaN Impatt are found to be of the order of few GHz, thereby indicating their high photo-sensitiveness at Sub-millimeter or Terahertz domain.

  14. Numerical study of sub-millimeter Gunn oscillations in InP and GaN vertical diodes: Dependence on bias, doping, and length

    Science.gov (United States)

    García, S.; Íñiguez-de-la-Torre, I.; Pérez, S.; Mateos, J.; González, T.

    2013-08-01

    In this work, we report on Monte Carlo simulations of InP and GaN vertical Gunn diodes to optimize their oscillation frequency and DC to AC conversion efficiency. We show that equivalent operating conditions are achieved by the direct application of a sinusoidal AC voltage superimposed to the DC bias and by the simulation of the intrinsic device coupled with the consistent solution of a parallel RLC resonant circuit connected in series. InP diodes with active region about 1 μm offer a conversion efficiency up to 5.5% for frequencies around 225 GHz. By virtue of the larger saturation velocity, for a given diode length, oscillation frequencies in GaN diodes are higher than for InP structures. Current oscillations at frequencies as high as 675 GHz, with 0.1% efficiency, are predicted at the sixth generation band in a 0.9 μm-long GaN diode, corroborating the suitability of GaN to operate near the THz band. At the first generation band, structures with notch, in general, provide lower oscillation frequencies and efficiencies in comparison with the same structures without notch. However, a higher number of generation bands are originated in notched diodes, thus, typically reaching larger frequencies. Self-heating effects reduce the performance, but in GaN diodes the efficiency is not significantly degraded.

  15. Electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes: FFT-impedance spectroscopy of the growth process and magnetic properties

    Science.gov (United States)

    2014-01-01

    The electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes has been investigated by fast Fourier transform-impedance spectroscopy (FFT-IS) in the frequency range from 75 Hz to 18.5 kHz. The impedance data could be fitted very well using an electric circuit equivalent model with a series resistance connected in series to a simple resistor-capacitor (RC) element and a Maxwell element. Based on the impedance data, the Co deposition in ultra-high aspect ratio InP membranes can be divided into two different Co deposition processes. The corresponding share of each process on the overall Co deposition can be determined directly from the transfer resistances of the two processes. The impedance data clearly show the beneficial impact of boric acid on the Co deposition and also indicate a diffusion limitation of boric acid in ultra-high aspect ratio InP membranes. The grown Co nanowires are polycrystalline with a very small grain size. They show a narrow hysteresis loop with a preferential orientation of the easy magnetization direction along the long nanowire axis due to the arising shape anisotropy of the Co nanowires. PMID:25050088

  16. Electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes: FFT-impedance spectroscopy of the growth process and magnetic properties

    Science.gov (United States)

    Gerngross, Mark-Daniel; Carstensen, Jürgen; Föll, Helmut

    2014-06-01

    The electrochemical growth of Co nanowires in ultra-high aspect ratio InP membranes has been investigated by fast Fourier transform-impedance spectroscopy (FFT-IS) in the frequency range from 75 Hz to 18.5 kHz. The impedance data could be fitted very well using an electric circuit equivalent model with a series resistance connected in series to a simple resistor-capacitor ( RC) element and a Maxwell element. Based on the impedance data, the Co deposition in ultra-high aspect ratio InP membranes can be divided into two different Co deposition processes. The corresponding share of each process on the overall Co deposition can be determined directly from the transfer resistances of the two processes. The impedance data clearly show the beneficial impact of boric acid on the Co deposition and also indicate a diffusion limitation of boric acid in ultra-high aspect ratio InP membranes. The grown Co nanowires are polycrystalline with a very small grain size. They show a narrow hysteresis loop with a preferential orientation of the easy magnetization direction along the long nanowire axis due to the arising shape anisotropy of the Co nanowires.

  17. Evaluating the Performance of the CPTEC-INPE/FCT-UNESP Troposphere Dynamic Model Using the VRS Concept

    Science.gov (United States)

    Alves, D. B.; Dalbelo, L. F.; Monico, J. F.; Sapucci, L. F.

    2007-05-01

    Nowadays, the use of Zenithal Tropospheric Delay (ZTD) prediction from Numeric Weather Prediction (NWP) models is a good alternative to minimize the effects of the troposphere in the radio frequency signs for real time and/or pos-processed applications. This process is denominated here after ZTD dynamic modeling. In Brazil, the procedure used to compute the ZTD by the NWP model was jointly developed by researchers from UNESP (São Paulo State University) and CPTEC (Center for Weather Forecasting and Climate Studies) of the INPE (National Institute for Space Research). The ZTD values are provided for all South America twice a day with predictions for a period of 66 hours. The database and the quality analysis are available by CPTEC-INPE in http:satelite.cptec.inpe.br/htmldocs/ztd/zenital.htm. In order to test the performance of the ZTD dynamic modeling in positioning applications, some experiments were carried out. Besides, the results obtained with dynamic modeling were compared with those obtained by Hopfield empirical model. These two tropospheric models were used to generate a VRS (Virtual Reference Station). In the VRS concept developed in this research, a reference station is generated near the user using data provided by a reference network station and atmospheric models. Therefore, the VRS data are not provided by a real receiver. But, the idea is that the VRS data resemble as much as possible a real receiver data at the same location. Therefore, the user has the possibility of using the VRS as if it were a real reference station in your proximities, and to accomplish the relative positioning with a single frequency receiver. This method was implemented in an software which has been developed at UNESP. In order to test the discussed method it was accomplished two experiments using data from two different networks: (a) Brazilian Continuous GPS Network (RBMC) and some extra stations; (b) GPS Active Network of West of São Paulo State. Using the first network

  18. Ultrafast Carrier Dynamics Measured by the Transient Change in the Reflectance of InP and GaAs Film

    Energy Technology Data Exchange (ETDEWEB)

    Klopf, John [Helmholtz Association of German Research Centers, Dresden (Germany)

    2005-10-31

    Advancements in microfabrication techniques and thin film growth have led to complex integrated photonic devices, also known as optoelectronics. The performance of these devices relies upon precise control of the band gap and optical characteristics of the thin film structures, as well as a fundamental understanding of the photoexcited carrier thermalization, relaxation, and recombination processes. An optical pump-probe technique has been developed to measure the transient behavior of these processes on a sub-picosecond timescale. This method relies upon the generation of hot carriers by theabsorption of an intense ultrashort laser pulse (~ 135 fs). The transient changes in reflectance due to the pump pulse excitation are monitored using a weaker probe pulse. Control of the relative time delay between the pump and probe pulses allows for temporal measurements with resolution limited only by the pulse width. The transient change in reflectance is the result of a transient change in the carrier distribution. Observation of the reflectance response of indium phosphide (InP) and gallium arsenide (GaAs) films on a sub-picosecond timescale allows for detailed examination of thermalization and relaxation processes of the excited carriers. Longer timescales (> 100 ps) are useful for correlating the transient reflectance response to slower processes such as the diffusion and recombination of the photoexcited carriers. This research investigates the transient hot carrier processes in several InP and GaAs based films similar to those commonly used in optoelectronics. This technique is especially important as it provides a non-destructive means of evaluating these materials; whereas much of the research performed in this field has relied upon the measurement of transient changes in the transmission of transparent films. The process of preparing films that are transparent renders them unusable in functioning devices. This research should not only extend the understanding of

  19. Contribuição de diversos sistemas de observação na previsão de tempo no CPTEC/INPE Contribution of the several observation systems in the forecast skill at CPTEC/INPE

    Directory of Open Access Journals (Sweden)

    Rita V. Andreoli

    2008-06-01

    Full Text Available Experimentos utilizando sistemas de observação global, foram realizados excluindo um ou mais tipos de observação do esquema global de assimilação de dados/previsão de tempo do Centro de Previsão de Tempo e Estudos Climáticos do Instituto Nacional de Pesquisas Espaciais - CPTEC/INPE (Global Physical-space Statistical Analysis System - GPSAS. Estes experimentos indicam como efetivamente as observações são usadas no GPSAS. Os sistemas de observação testados foram o conjunto de dados convencionais, que incluem informações de superfície (estações em superfície, bóias, navios e plataformas oceânicas e de ar superior (radiossondagem, aeronaves e balões piloto, os sistemas de sondagem Advanced TIROS-N/NOAA Operational Vertical Sounder (ATOVS e AQUA, composto pelos sensores Atmospheric Infrared Sounder e Advanced Microwave Sounding Unit (AIRS/AMSU, dados de vento de satélite, estimados a partir do deslocamento de nuvens (Cloud Track Wind, dados de vento em superfície sobre o oceano (QuikScat e água precipitável (Total Precipitation water - TPW. Todos os sistemas testados mostram um impacto positivo na qualidade da previsão. Os dados convencionais têm um maior impacto na região do Hemisfério Norte devido à maior disponibilidade dessas informações sobre esta região. Por outro lado, as sondagens AIRS/AMSU são fundamentais para uma boa previsão sobre o Hemisfério Sul. Sobre a América do Sul, os perfis inferidos pelo sistema de sondagem AQUA contribuem com a mesma ordem de grandeza dos dados convencionais e apresentam um impacto positivo para todos os períodos de previsões analisados. Dados de vento e água precipitável estimados por satélites têm maior impacto nas regiões tropical e da América do Sul, nas primeiras horas de previsão (1-3 dias. Todavia, a utilização de um conjunto completo de observações é crucial para se obter, operacionalmente, uma boa condição inicial do estado atmosférico para ser

  20. Effect of defects due to lattice mismatch between GaAs and InP materials on gate-leakage current and microwave noise of GaAs MESFETS on InP substrates

    Science.gov (United States)

    Chertouk, Mourad; Boudiaf, A.; Azoulay, Rozette; Clei, A.

    1993-11-01

    The effect of traps due to lattice mismatch between GaAs and InP materials on the reverse current of Schottky diodes is demonstrated by the temperature dependence of the current, which exhibits a S.R.H. component at low reverse bias (also present in GaAs/GaAs with activation energy 0.125 eV) and a trap assisted tunneling one at high reverse bias (not observed in GaAs/GaAs). A model is developed which takes into account the temperature and channel doping level dependence. Application of this model to 0.25 micrometers gate GaAs MESFETs gives a good agreement with gate leakage current behavior as a function of drain and gate bias, for 6 X 1017 cm-3 and 1018 cm-3 channel doping. The excess gate-drain assisted tunneling current in 1018 cm-3 doped channel does not affect the MESFETs dc and microwave performances. However, the microwave noise (Fmin) is increased.

  1. Impacto da utilização de previsões "defasadas" no sistema de previsão de tempo por conjunto do CPTEC/INPE The impact of using lagged forecasts on the CPTEC/INPE ensemble prediction system

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Ribas Machado

    2010-03-01

    Full Text Available Neste trabalho é descrita a aplicação da técnica de previsões defasadas no sistema de previsão de tempo por conjuntos do Centro de Previsão de Tempo e Estudos Climáticos (EPS-CPTEC/INPE. Os dados do CPTEC/INPE consistem em uma amostra de dois meses com previsões de 15 dias para as variáveis: altura geopotencial em 500 hPa, temperatura do ar no nível de 850 hPa, e pressão atmosférica ao nível médio do mar. O estudo consiste em investigar: 1 o desempenho do EPS-CPTEC/INPE utilizando a técnica de previsões defasadas comparado àquele do conjunto operacional; 2 a relação entre o espalhamento e o desempenho da previsão, a fim de avaliar o uso da dispersão como preditor do desempenho. Os resultados indicam que a utilização de previsões defasadas em 12h, melhora o desempenho do conjunto operacional, contribuindo para aumentar o espalhamento do conjunto e, conseqüentemente, reduzir a sub-dispersão do sistema. Também foi observado que o conjunto defasado tem desempenho comparável àquele do conjunto operacional e que há uma tendência de desempenho alto quando o espalhamento é baixo, para os prazos de 5 e 7 dias de previsão. Estes resultados servem como base para a implementação operacional desta técnica, que apresenta baixo custo computacional, e contribui para a utilização mais eficiente das previsões por conjunto do CPTEC/INPE.In this work we report the application of the lagged average forecasting technique to CPTEC/INPE ensemble forecast. The CPTEC/INPE data consist of two months samples of 15 days forecast for the variables: geopotential height at 500 hPa, air temperature at 850 hPa and mean sea level atmospheric pressure. We focus on the following: 1 Does the lagged averaged ensemble forecast improve forecast skill compared to the CPTEC/INPE operational ensemble? 2 Is the dispersion of the ensemble useful in predicting forecast skill? The results indicate that the utilization of 12h-lagged average forecasts

  2. Efficient Coupling of an Antenna-Enhanced nanoLED into an Integrated InP Waveguide.

    Science.gov (United States)

    Eggleston, Michael S; Wu, Ming C

    2015-05-13

    Increasing power consumption in traditional on-chip metal interconnects has made optical links an attractive alternative. However, such a link is currently missing a fast, efficient, nanoscale light-source. Coupling nanoscale optical emitters to optical antennas has been shown to greatly increase their spontaneous emission rate and efficiency. Such a structure would be an ideal emitter for an on-chip optical link. However, there has never been a demonstration of an antenna-enhanced emitter coupled to a low-loss integrated waveguide. In this Letter we demonstrate an optical antenna-enhanced nanoLED coupled to an integrated InP waveguide. The nanoLEDs are comprised of a nanoridge of InGaAsP coupled to a gold antenna that exhibits a 36× enhanced rate of spontaneous emission. Coupling efficiencies as large as 70% are demonstrated into an integrated waveguide. Directional antennas also demonstrate direction emission down one direction of a waveguide with observed front-to-back ratios as high as 3:1.

  3. Defect-related luminescence in InAlAs on InP grown by molecular beam epitaxy

    Science.gov (United States)

    Gilinsky, A. M.; Dmitriev, D. V.; Toropov, A. I.; Zhuravlev, K. S.

    2017-09-01

    The photoluminescence (PL) of InAlAs grown on InP has been studied in a wide range of temperatures and excitation intensities. A novel emission ascribed to the presence of defects has been found by about 120-180 meV below the near band edge (NBE) line. The novel wide PL band is observed in the spectra only in a limited range of temperatures of 50-160 K, and is seen neither at liquid helium nor at room temperatures. The analysis of the PL behaviour with sample temperature and excitation power together with non-stationary PL kinetics allows us to conclude that both the NBE PL and the novel PL band are controlled by transitions via states of band tails formed due to alloy disorder in these films. The NBE PL is caused by recombination of carriers in the band tails, while deep levels related to defects and located in the same regions as the deepest band tail states are supposedly involved in the defect-related PL transitions. We demonstrate that no defect-related PL is found in the spectra if quasi-stoichiometric growth conditions were used during film growth, which resulted in a PL efficiency by about 1-2 orders of magnitude greater than that of samples grown under more common As-rich conditions.

  4. 93-133 GHz Band InP High-Electron-Mobility Transistor Amplifier with Gain-Enhanced Topology

    Science.gov (United States)

    Sato, Masaru; Shiba, Shoichi; Matsumura, Hiroshi; Takahashi, Tsuyoshi; Nakasha, Yasuhiro; Suzuki, Toshihide; Hara, Naoki

    2013-04-01

    In this study, we developed a new type of high-frequency amplifier topology using 75-nm-gate-length InP-based high-electron-mobility transistors (InP HEMTs). To enhance the gain for a wide frequency range, a common-source common-gate hybrid amplifier topology was proposed. A transformer-based balun placed at the input of the amplifier generates differential signals, which are fed to the gate and source terminals of the transistor. The amplified signal is outputted at the drain node. The simulation results show that the hybrid topology exhibits a higher gain from 90 to 140 GHz than that of the conventional common-source or common-gate amplifier. The two-stage amplifier fabricated using the topology exhibits a small signal gain of 12 dB and a 3-dB bandwidth of 40 GHz (93-133 GHz), which is the largest bandwidth and the second highest gain reported among those of published 120-GHz-band amplifiers. In addition, the measured noise figure was 5 dB from 90 to 100 GHz.

  5. 225-255-GHz InP DHBT Frequency Tripler MMIC Using Complementary Split-Ring Resonator

    Science.gov (United States)

    Li, Xiao; Zhang, Yong; Li, Oupeng; Sun, Yan; Lu, Haiyan; Cheng, Wei; Xu, Ruimin

    2016-10-01

    In this paper, a novel design of frequency tripler monolithic microwave integrated circuit (MMIC) using complementary split-ring resonator (CSRR) is proposed based on 0.5-μm InP DHBT process. The CSRR-loaded microstrip structure is integrated in the tripler as a part of impedance matching network to suppress the fundamental harmonic, and another frequency tripler based on conventional band-pass filter is presented for comparison. The frequency tripler based on CSRR-loaded microstrip generates an output power between -8 and -4 dBm from 228 to 255 GHz when the input power is 6 dBm. The suppression of fundamental harmonic is better than 20 dBc at 77-82 GHz input frequency within only 0.15 × 0.15 mm2 chip area of the CSRR structure on the ground layer. Compared with the frequency tripler based on band-pass filter, the tripler using CSRR-loaded microstrip obtains a similar suppression level of unwanted harmonics and higher conversion gain within a much smaller chip area. To our best knowledge, it is the first time that CSRR is used for harmonic suppression of frequency multiplier at such high frequency band.

  6. Surface chemistry of InP ridge structures etched in Cl{sub 2}-based plasma analyzed with angular XPS

    Energy Technology Data Exchange (ETDEWEB)

    Bouchoule, Sophie, E-mail: sophie.bouchoule@lpn.cnrs.fr; Cambril, Edmond; Guilet, Stephane [Laboratoire de Photonique et Nanostructure (LPN)—UPR20, CNRS, Route de Nozay, 91460 Marcoussis (France); Chanson, Romain; Pageau, Arnaud; Rhallabi, Ahmed; Cardinaud, Christophe, E-mail: christophe.cardinaud@cnrs-imn.fr [Institut des matériaux Jean Rouxel (IMN), UMR6502, Université de Nantes, CNRS, 44322 Nantes (France)

    2015-09-15

    Two x-ray photoelectron spectroscopy configurations are proposed to analyze the surface chemistry of micron-scale InP ridge structures etched in chlorine-based inductively coupled plasma (ICP). Either a classical or a grazing configuration allows to retrieve information about the surface chemistry of the bottom surface and sidewalls of the etched features. The procedure is used to study the stoichiometry of the etched surface as a function of ridge aspect ratio for Cl{sub 2}/Ar and Cl{sub 2}/H{sub 2} plasma chemistries. The results show that the bottom surface and the etched sidewalls are P-rich, and indicate that the P-enrichment mechanism is rather chemically driven. Results also evidence that adding H{sub 2} to Cl{sub 2} does not necessarily leads to a more balanced surface stoichiometry. This is in contrast with recent experimental results obtained with the HBr ICP chemistry for which fairly stoichiometric surfaces have been obtained.

  7. Investigation of chlorine-based etchants in wet and dry etching technology for an InP planar Gunn diode

    Science.gov (United States)

    Bai, Yang; Jia, Rui; Wu, De-Qi; Jin, Zhi; Liu, Xin-Yu; Lin, Mei-Yu

    2013-08-01

    Mesa etching technology is considerably important in the Gunn diode fabrication process. In this paper we fabricate InP Gunn diodes with two different kinds of chlorine-based etchants for the mesa etching for comparative study. We use two chlorine-based etchants, one is HCl-based solution (HCl/H3PO4), and the other is Cl2-based gas mixture by utilizing inductively coupled plasma system (ICP). The results show that the wet etching (HCl-based) offers low cost and approximately vertical sidewall, whilst ICP system (Cl2-based) offers an excellent and uniform vertical sidewall, and the over-etching is tiny on the top and the bottom of mesa. And the fabricated mesas of Gunn diodes have average etching rates of ~ 0.6 μm/min and ~ 1.2 μm/min, respectively. The measured data show that the current of Gunn diode by wet etching is lower than that by ICP, and the former has a higher threshold voltage. It provides a low-cost and reliable method which is potentially applied to the fabrication of chip terahertz sources.

  8. Investigation of chlorine-based etchants in wet and dry etching technology for an InP planar Gunn diode

    Institute of Scientific and Technical Information of China (English)

    Bai Yang; Jia Rui; Wu De-Qi; Jin Zhi; Liu Xin-Yu; Lin Mei-Yu

    2013-01-01

    Mesa etching technology is considerably important in the Gunn diode fabrication process.In this paper we fabricate InP Gunn diodes with two different kinds of chlorine-based etchants for the mesa etching for comparative study.We use two chlorine-based etchants,one is HCl-based solution (HCl/H3PO4),and the other is Cl2-based gas mixture by utilizing inductively coupled plasma system (ICP).The results show that the wet etching (HCl-based) offers low cost and approximately vertical sidewall,whilst ICP system (Cl2-based) offers an excellent and uniform vertical sidewall,and the over-etching is tiny on the top and the bottom of mesa.And the fabricated mesas of Gunn diodes have average etching rates of ~ 0.6 μm/min and ~ 1.2 μm/min,respectively.The measured data show that the current of Gunn diode by wet etching is lower than that by ICP,and the former has a higher threshold voltage.It provides a low-cost and reliable method which is potentially applied to the fabrication of chip terahertz sources.

  9. 225-255-GHz InP DHBT Frequency Tripler MMIC Using Complementary Split-Ring Resonator

    Science.gov (United States)

    Li, Xiao; Zhang, Yong; Li, Oupeng; Sun, Yan; Lu, Haiyan; Cheng, Wei; Xu, Ruimin

    2017-02-01

    In this paper, a novel design of frequency tripler monolithic microwave integrated circuit (MMIC) using complementary split-ring resonator (CSRR) is proposed based on 0.5-μm InP DHBT process. The CSRR-loaded microstrip structure is integrated in the tripler as a part of impedance matching network to suppress the fundamental harmonic, and another frequency tripler based on conventional band-pass filter is presented for comparison. The frequency tripler based on CSRR-loaded microstrip generates an output power between -8 and -4 dBm from 228 to 255 GHz when the input power is 6 dBm. The suppression of fundamental harmonic is better than 20 dBc at 77-82 GHz input frequency within only 0.15 × 0.15 mm2 chip area of the CSRR structure on the ground layer. Compared with the frequency tripler based on band-pass filter, the tripler using CSRR-loaded microstrip obtains a similar suppression level of unwanted harmonics and higher conversion gain within a much smaller chip area. To our best knowledge, it is the first time that CSRR is used for harmonic suppression of frequency multiplier at such high frequency band.

  10. Balanced G-band Gm-boosted frequency doublers in transferred substrate InP HBT technology

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Thualfiqar, Al-Sawaf; Weimann, Nils

    2016-01-01

    In this paper, balanced G-band Gm-boosted frequency doublers in transferred substrate (TS) InP HBT technology are reported for the first time. The Gm-boosted frequency doublers consist of a phase compensated Marchand balun, Gm-boosted doubler stage, and an optional cascode gain stage at the output....... The doubler without cascode demonstrates a maximum output power of +4.7 dBm around a narrow frequency range at 200 GHz when driven with an input power of +10 dBm. A Gm-boosted frequency doubler with cascode demonstrates an output power of +5.4 dBm at 190 GHz when driven with an input power of +11 d......Bm. The power consumptions of the Gm-boosted frequency doubler without and with cascode are 30.9 mW and 56.4 mW, respectively. The fundamental suppression for both doublers remains better than 17.3 dB over an input frequency range of 75–110 GHz....

  11. Construção, usos sociais e busca de legitimidade das tecnologias da geoinformação do INPE | Construction, social uses and legitimation of geioinformational technologies at INPE

    Directory of Open Access Journals (Sweden)

    Paulo Augusto Sobral Escada

    2012-04-01

    Full Text Available Resumo Este artigo analisa a experiência de um grupo de cientistas e especialistas do Instituto Nacional de Pesquisas Espaciais (INPE que buscou consolidar e legitimar, ao longo de duas décadas, um modo próprio de produção de conhecimento científico e tecnológico. Mudanças de paradigma da Política de C&T, nos anos 1990, retiraram o apoio governamental de seus desenvolvimentos, obrigando-os a mudar suas ações estratégicas para que permitisse manter e preservar o modelo endógeno e autônomo de produção do conhecimento. O artigo trabalha com a perspectiva de Pierre Bourdieu (2001, aplicada ao campo científico, e a noção de “translação” de Bruno Latour (2000. A abordagem sociológica contempla e naturaliza os jogos de interesses e disputas no interior do campo científico, bem como destaca o processo de legitimação científica e social do conhecimento. O artigo tem como objetivo principal oferecer uma contribuição aos processos de discussão do modelo das políticas de CTI, principalmente na definição dos conhecimentos a serem produzidos e absorvidos pelo processo de desenvolvimento econômico e social do país. O artigo destaca a necessidade de se ampliar e aprofundar mecanismos democráticos, adotando maior inclusão e transparência nas disputas do campo científico e das políticas de C&T, condições básicas para alcançar um consenso geral que permita emergir um desenvolvimento desejado e planejado por boa parte da sociedade. Palavras-chave Sociologia do Conhecimento, produção de conhecimento, legitimação, democracia e desenvolvimento Abstract This article analyzes the experience of a group of scientists and specialists from the National Institute of Space Research (INPE who aimed to consolidate and legitimize, throughout two decades, its own way of producing scientific and technological knowledge. Changes of paradigm in Science, Technology and Innovation (STI Politics, during the 90s, removed governmental

  12. 基于元素磷源的InP量子点的制备%Synthesis of InP Quantum Dots with Elemental Phosphine Source

    Institute of Scientific and Technical Information of China (English)

    王彬彬; 王莉; 汪瑾; 蒋阳

    2012-01-01

    The InP quantum dots (QDs) were synthesized via a colloidal chemical method with white phosphorus (P4), indium acetate (In (Ac)3), stearic acid and 1-octadecene (ODE) as phosphorus source, indium source, surfactant and solvent, respectively. The structure, size and shape of the quantum dots were analyzed by XRD and TEM. The resulting InP QDs were also characterized by UV-Visible absorption and fluorescence spectroscopy. The title material exhibits well-resolved absorption and emission properties. Meanwhile, the InP QDs emit at 415~517 nm in the electromagnetic spectrum showing obvious quantum size effect.%以白磷作为磷源、醋酸铟为铟源、硬脂酸为表面包覆剂、十八烯为溶剂,采用胶体化学法合成了InP量子点.X射线衍射(XRD)和透射电子显微镜(TEM)分析测试显示InP量子点属于立方闪锌矿结构,并且是直径约为5 nm的球状纳米晶.紫外可见光谱和荧光光谱分析表明,InP量子点表现出明显的激子吸收和带边发射特征,荧光发射光谱在415~517 nm范围内连续可调,呈现明显的量子尺寸效应.

  13. Characterization of semi-insulating materials by photoinduced current transient spectroscopy: Fe doped INP for micro-optoelectronics and CdZnTe for nuclear detection; Caracterisation de materiaux semi-isolants par spectroscopie de transitoirede courant photoinduit: materiaux INP dopes Fe pour la micro-optoelectronique et CDZNTE pour la detection nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Cherkaoui, K

    1998-07-01

    The need of semi-insulating materials, of great quality, concerns various application domains. For instance, the very resistive substrates InP and CdZnTe are respectively adapted to the micro-optoelectronic circuits and to nuclear detectors. These two materials have been characterized by the thermal photoinduced current transient spectroscopy. The first part of this thesis is the defects analysis of annealing InP substrates, to understand the compensation process of this material. Two activation energy levels around 0,2 to 0,4 eV resulting from the thermal treatment have been detected. The iron omnipresence in the substrates, even undoped, has been noticed. It is then necessary to take into account the iron presence to understand the compensation process in these InP annealing substrates. the second part presents the study of the CdZnTe material, elaborated by the Bridgman method, to emphasize the defects leading to the decrease of the detector performances. The presence of three deep levels, near the forbidden band middle, is in relation with the detectors performances. (A.L.B.)

  14. Native oxides formation and surface wettability of epitaxial III-V materials: The case of InP and GaAs

    Science.gov (United States)

    Gocalinska, A.; Rubini, S.; Pelucchi, E.

    2016-10-01

    The time dependent transition from hydrophobic to hydrophilic states of the metalorganic vapour phase epitaxy (MOVPE) grown InP, GaAs and InAs is systematically documented by contact angle measurements. Natural oxides forming on the surfaces of air-exposed materials, as well as the results of some typical wet chemical process to remove those oxides, were studied by X-ray photoemission spectroscopy (XPS), revealing, surprisingly, a fundamental lack of strong correlations between the surface oxide composition and the reported systematic changes in hydrophobicity.

  15. Wavelength Conversion of a 9.35-Gb/s RZ OOK Signal in an InP Photonic Crystal Nanocavity

    DEFF Research Database (Denmark)

    Vukovic, Dragana; Yu, Yi; Heuck, Mikkel

    2014-01-01

    Wavelength conversion of a 10-Gb/s (9.35 Gb/s net rate) return-to-zero ON-OFF keying signal is demonstrated using a simple InP photonic crystal H0 nanocavity with Lorentzian line shape. The shifting of the resonance induced by the generation of free-carriers enables the pump intensity modulation...... to be transferred to a continuous-wave probe with a sufficiently high quality so that the converted signal can be detected with a conventional telecommunication receiver. A clear eye diagram is observed for the converted signal showing a pre-forward error correction bit-error-ratio down to $10^{-3}$....

  16. Charge storage properties of InP quantum dots in GaAs metal-oxide-semiconductor based nonvolatile flash memory devices

    Science.gov (United States)

    Kundu, Souvik; Halder, Nripendra N.; Biswas, Pranab; Biswas, D.; Banerji, P.; Mukherjee, Rabibrata; Chakraborty, S.

    2012-11-01

    Metal organic vapor phase epitaxially grown 5 nm InP quantum dots (QDs) were embedded as charge storage elements between high-k control and tunneling dielectric layers in GaAs metal-oxide-semiconductor based nonvolatile memory devices. The QDs trap more electrons resulting in a large memory window (6.3 V) along with low leakage due to Coulomb blockade effect. 16.5% charge loss was found even after 105 s indicating its good charge storing potential. The programming and erasing operations were discussed with proposed band diagram.

  17. Influence of the oxide aperture radius on the mode spectra of (Al,Ga)As vertical microcavities with electrically excited InP quantum dots

    Science.gov (United States)

    Weidenfeld, S.; Schulz, W.-M.; Kessler, C. A.; Reischle, M.; Eichfelder, M.; Wiesner, M.; Jetter, M.; Michler, P.

    2013-01-01

    In this letter, we report about mode characteristics of microcavity lasers with red-emitting InP quantum dots. The mode spectra and the quality factor of devices with different oxide aperture sizes are analyzed. The lateral mode confinement in the electrical devices is defined via oxide apertures. We found a good agreement between a simple analytical modeling of the mode structure and measurements, which allows to adjust the design of future devices. The quality factors show an analogous behavior as etched micropillars. The enhanced intensity of the higher order modes compared to the fundamental mode can be explained with the current density distribution within the device favoring higher order modes.

  18. Monolithic integration on InP of a Wannier Stark modulator with a strained MQW DFB 1.55-micron laser

    Science.gov (United States)

    Allovon, Michel; Fouchet, Sylvie; Harmand, Jean-Christophe; Ougazzaden, Abdallah; Rose, Benoit; Gloukhian, Andre; Devaux, Fabrice

    1995-02-01

    We present the technical approach and the preliminary device results on the first integration of a Wannier Stark (WS) electroabsorption (EA) modulator with a DFB laser on InP. The WS modulator active layer consists of a lattice matched InGaAs-InAlAs superlattice (SL) grown by solid source MBE (Molecular Beam Epitaxy). It is butt-coupled to a laser grown by AP-MOVPE whose active layer includes a strained InGaAsP-InGaAsP MQW stack. Device results cover static performances of integrated lasers and modulators, and measurements of high frequency characteristics (small signal bandwidth and 10 Gb/s eye diagram).

  19. Optical and electrical properties of InP/InGaAs grown selectively on SiO2-masked InP

    Science.gov (United States)

    Wang, Y. L.; Feygenson, A.; Hamm, R. A.; Ritter, D.; Weiner, J. S.; Temkin, H.; Panish, M. B.

    1991-07-01

    Heterostructures of InGaAs/InP have been grown selectively through windows in SiO2-masked InP substrates using metalorganic molecular beam epitaxy. The structures show high cathodoluminescence efficiency for window sizes down to 5 μm. A significant red shift, consistent with compressive lattice strain, and reduced intensity are observed for smaller features. Anomalous growth is observed near the edges of the windows. Selectively grown InGaAs/InP p-n junctions and bipolar transistors exhibit excellent electrical characteristics after removal of 1-2 μm of edge material.

  20. Electrodeposition of epitaxial ZnSe films on InP and GaAs from an aqueous zinc sulfate-selenosulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Riveros, G.; Guillemoles, J.F.; Lincot, D. [Laboratoire d' Electrochimie et de Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Gomez Meier, H. [Instituto de Chimica, Faculdad de Ciencas Basicas y Matematicas, Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casila, Valparaiso (Chile); Froment, M.; Bernard, M.C.; Cortes, R. [Laboratoire de Physique des Liquides et Electrochimie (UPR CNRS 15), Universite Pierre et Marie Curie, 4 place Jussieu, F-75232 Paris Cedex 05 (France)

    2002-09-16

    Epitaxial growth of ZnSe thin films on InP(111) and GaAs(100) substrates has been achieved by electrodeposition from a zinc sulfate/selenosulfate solution. The deposition was observed over a wide range of applied potentials (-1.6-1.9 V vs. mercury/mercury sulfate). The epitaxy was characterized by reflective high energy electron diffraction (see Figure for a ZnSe epitaxial layer) and grazing angle X-ray diffraction. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  1. Evaluation of test structures for the novel n{sup +}-in-p pixel and strip sensors for very high radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Unno, Y., E-mail: yoshinobu.unno@kek.jp [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Mitsui, S. [The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Hori, R.; Ikegami, Y.; Terada, S. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Kamada, S.; Yamamura, K. [Solid-state Division, Hamamatsu Photonics K.K., 1126-1 Ichino-cho, Higashi-ku, Hamamatsu-shi 435-8558 (Japan); Hanagaki, K. [Department of Physics, Osaka University, Machikaneyama-cho, Toyonaka-shi, Osaka 560-0043 (Japan); Hara, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi 305-8571 (Japan); Jinnouchi, O. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Kimura, N. [Research Institute for Science and Engineering, Waseda University, 1-6-1 Nishi-Waseda, Shinjuku-ku, Tokyo 169-8050 (Japan); Nagai, K. [Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi 305-8571 (Japan); Nakano, I. [Department of Physics, Okayama University, 3-1-1 Tshushima-naka, Kita-ku, Okayama-shi 700-8530 (Japan); Oda, S. [Department of Physics, Kyushu University, 6-10-11 Hakozaki, Higashi-ku, Fukuoka-shi 812-8581 (Japan); Takashima, R. [Department of Education, Kyoto University of Education, 1 Fukakusa-Fujimori-cho, Fushimi-ku, Kyoto 612-8522 (Japan); Takubo, Y. [Institute of Particle and Nuclear Study, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi 305-0801 (Japan); Tojo, J. [Department of Physics, Kyushu University, 6-10-11 Hakozaki, Higashi-ku, Fukuoka-shi 812-8581 (Japan); and others

    2013-12-11

    Radiation-tolerant n{sup +}-in-p silicon sensors were developed for use in very high radiation environments. Novel n{sup +}-in-p silicon strip and pixel sensors and test structures were fabricated, tested and evaluated, in order to understand the designs implemented. The resistance between the n{sup +} implants (interstrip resistance), the electric potential of the p-stop, and the punch-through-protection (PTP) onset voltage were measured before and as a function of fluence after irradiation. The technology computer-aided design (TCAD) simulations were used to understand the radiation damage and fluence dependence of the structures. The decrease in the interstrip resistance is a consequence of increased leakage current. The decrease in the electric potential of the p-stop results from a build-up of positive charge in the silicon–silicon oxide interface. The decrease and subsequent increase in the PTP onset voltages results from the interface charge build-up and an increase in acceptor states.

  2. Investigation of p-side contact layers for II-VI compound semiconductor optical devices fabricated on InP substrates by MBE

    Science.gov (United States)

    Takamatsu, Shingo; Nomura, Ichirou; Shiraishi, Tomohiro; Kishino, Katsumi

    2015-09-01

    N-doped p-type ZnTe and ZnSeTe contact layers were investigated to evaluate which is more suitable for use in II-VI compound semiconductor optical devices on InP substrates. Contact resistances (Rc) between the contact layers and several electrode materials (Pd/Pt/Au, Pd/Au, and Au) were measured by the circular transmission line model (c-TLM) method using p-n diode samples grown on InP substrates by molecular beam epitaxy (MBE). The lowest Rc (6.5×10-5 Ω cm2) was obtained in the case of the ZnTe contact and Pd/Pt/Au electrode combination, which proves that the combination is suitable for obtaining low Rc. Yellow light-emitting diode devices with a ZnTe and ZnSeTe p-contact layer were fabricated by MBE to investigate the effect of different contact layers. The devices were characterized under direct current injections at room temperature. Yellow emission at around 600 nm was observed for each device. Higher emission intensity and lower slope resistance were obtained for the device with the ZnTe contact layer and Pd/Pt/Au electrode compared with other devices. These device performances are ascribed to the low Rc of the ZnTe contact and Pd/Pt/Au electrode combination.

  3. A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology

    Science.gov (United States)

    Ou-Peng, Li; Yong, Zhang; Rui-Min, Xu; Wei, Cheng; Yuan, Wang; Bing, Niu; Hai-Yan, Lu

    2016-05-01

    Design and characterization of a G-band (140-220 GHz) terahertz monolithic integrated circuit (TMIC) amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm InGaAs/InP double heterojunction bipolar transistor (DHBT). An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the InP substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140-190 GHz respectively. The saturation output powers are -2.688 dBm at 210 GHz and -2.88 dBm at 220 GHz, respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications. Project supported by the National Natural Science Foundation of China (Grant No. 61501091) and the Fundamental Research Funds for the Central Universities of Ministry of Education of China (Grant Nos. ZYGX2014J003 and ZYGX2013J020).

  4. Enhanced Photocatalytic Reduction of CO2 to CO through TiO2 Passivation of InP in Ionic Liquids.

    Science.gov (United States)

    Zeng, Guangtong; Qiu, Jing; Hou, Bingya; Shi, Haotian; Lin, Yongjing; Hettick, Mark; Javey, Ali; Cronin, Stephen B

    2015-09-21

    A robust and reliable method for improving the photocatalytic performance of InP, which is one of the best known materials for solar photoconversion (i.e., solar cells). In this article, we report substantial improvements (up to 18×) in the photocatalytic yields for CO2 reduction to CO through the surface passivation of InP with TiO2 deposited by atomic layer deposition (ALD). Here, the main mechanisms of enhancement are the introduction of catalytically active sites and the formation of a pn-junction. Photoelectrochemical reactions were carried out in a nonaqueous solution consisting of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4), dissolved in acetonitrile, which enables CO2 reduction with a Faradaic efficiency of 99% at an underpotential of +0.78 V. While the photocatalytic yield increases with the addition of the TiO2 layer, a corresponding drop in the photoluminescence intensity indicates the presence of catalytically active sites, which cause an increase in the electron-hole pair recombination rate. NMR spectra show that the [EMIM](+) ions in solution form an intermediate complex with CO2(-), thus lowering the energy barrier of this reaction.

  5. Long-wavelength VCSELs with AlGaAsSb/AlAsSb Bragg mirrors lattice-matched on InP substrates

    Science.gov (United States)

    Almuneau, Guilhem; Hall, Eric M.; Nakagawa, Shigeru; Kim, Jin K.; Coldren, Larry A.

    2000-05-01

    The characterization of 1.55 micrometer room temperature (RT) electrically pumped monolithic vertical cavity surface emitting lasers (VCSELs) on InP is reported. By combining high refractive index-contrast AlGaAsSb/AlAsSb distributed Bragg mirrors (DBRs) and Esaki-junction-based active region, these results demonstrate that VCSELs operating at 1.55 micrometer and employing a reasonable number of mirror periods can be grown in a single epitaxial step. Regarding our first results with the same type of structure, some improvements have been achieved on the threshold current density (approximately equals 1 kA/cm2), and on the voltage drop in the DBRs. We also present in this paper the thermal conductivity of the As- Sb materials measured on both bulk layers and DBR stacks. The main performance-limiting factor appears to be the combination between the low thermal conduction of the quaternary alloys lattice-matched to InP, and the high energy-band offset between the high- and the low-index materials.

  6. Fabrication of a P-stabilized InP(0 0 1) surface at low pressure and temperature using t-butylphosphine (TBP)

    Science.gov (United States)

    Fukuda, Yasuo; Kumano, Hiroshi; Nakamura, Hiroyuki

    2004-09-01

    Fabrication of a P-stabilized InP(0 0 1)-(2 × 1) surface at low pressure and temperature using t-butylphosphine (TBP) has been studied. The (2 × 1) surface was fabricated at 260 °C using TBP (5 × 10 -6 Torr) cracked with a hot W-filament although the (2 × 4) structure was not changed by exposing to TBP (5 × 10 -6-1 × 10 -5 Torr) at 260-280 °C without the filament. Mass spectra of the cracked TBP indicate that the relative spectral intensities of P and P 2 are increased by 1.3-1.5 times higher than TBP without the filament, leading to the result that the surface can be fabricated at low pressure and temperature. The formation rate of the (2 × 1) surface by our method is higher by about one order of magnitude even at lower pressure and temperature than the reported ALE method. The (2 × 1) surface is stable at 260-280 °C in an ultrahigh vacuum. This suggests that atomic layer epitaxy (ALE) of InP can be performed at low pressure and temperature using the hot W-filament. The Auger electron spectroscopy (AES) result indicates that carbon contamination does not occur on the surface by adsorption of TBP cracked by the filament.

  7. Aqueous-solution growth of GaP and InP nanowires: a general route to phosphide, oxide, sulfide, and tungstate nanowires.

    Science.gov (United States)

    Xiong, Yujie; Xie, Yi; Li, Zhengquan; Li, Xiaoxu; Gao, Shanmin

    2004-02-06

    A general synthetic route has been developed for the growth of metal phosphide, oxide, sulfide, and tungstate nanowires in aqueous solution. In detail, cetyltrimethylammonium cations (CTA(+)) can be combined with anionic inorganic species along a co-condensation mechanism to form lamellar inorganic-surfactant intercalated mesostructures, which serve as both microreactors and reactants for the growth of nanowires. For example, GaP, InP, gamma-MnO(2), ZnO, SnS(2), ZnS, CdWO(4), and ZnWO(4) nanowires have been grown by this route. To the best of our knowledge, this is the first time that the synthesis of GaP and InP nanowires in aqueous solution has been achieved. This strategy is expected to extend to grow nanowires of other materials in solution or by vapor transport routes, since the nanowire growth of any inorganic materials can be realized by selecting an appropriate reaction and its corresponding lamellar inorganic-surfactant precursors.

  8. FAO UN-REDD- INPE Joint Programme on Forest Monitoring Systems based on RS and GIS techniques

    Science.gov (United States)

    Jonckheere, I. G.; FAO UN-REDD MRV Team

    2010-12-01

    Capacity Development and Training for National Forest Monitoring Systems for Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+) REDD+, which stands for ’Reducing Emissions from Deforestation and Forest Degradation in Developing Countries’ - is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. The UN-REDD Programme, a collaborative partnership between FAO, UNDP and UNEP launched in September 2008, supports countries to develop capacity to REDD+ and to implement a future REDD+ mechanism in a post-2012 climate regime. The programme works at both the national and global scale, through support mechanisms for country-driven REDD strategies and international consensus-building on REDD+ processes. The UN-REDD Programme gathers technical teams from around the world to develop common approaches, analyses and guidelines on issues such as measurement, reporting and verification (MRV) of carbon emissions and flows, remote sensing, and greenhouse gas inventories. Within the partnership, FAO supports countries on technical issues related to forestry and the development of cost effective and credible MRV processes for emission reductions. While at the international level, it fosters improved guidance on MRV approaches, including consensus on principles and guidelines for MRV and training programmes. It provides guidance on how best to design and implement REDD+, to ensure that forests continue to provide multiple benefits for livelihoods and biodiversity to societies while storing carbon at the same time. Other areas of work include national forest assessments and monitoring of in-country policy and institutional change. FAO and INPE (Brazilian Space Agency) have joint forces through a MoU signed last year in Copenhagen. A major joint programme has been agreed upon to set

  9. Activities report of the National Space Research Institute Plasma Laboratory for the period 1988/1989; Relatorio de atividades do Laboratorio Associado de Plasma do INPE no bienio 88/89

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Gerson Otto

    1990-11-01

    This report describes the activities performed in the period 1988/1989 by the National Space Research Institute (INPE/SCT) Plasma Laboratory (LAP). The report presents the main results in the following research lines: plasma physics, plasma technology, and controlled thermonuclear fusion. (author). 49 figs., 3 tabs.

  10. Depósito mediante ablación con láser de láminas delgadas de (Pb,La TiO3 y ZnO sobre (100 InP

    Directory of Open Access Journals (Sweden)

    Román, E.

    1999-10-01

    Full Text Available The oriented growth of PbLaTiO3 (PLT and ZnO thin films on (100InP has been studied, including the influence of buffer oxide layers (CeO2, ZrO2, SrO, YSZ, MgO, and SrTiO3 on the final texture of PLT film obtained. In each case the oxygen pressure, substrate temperature, energy fluence and substrate surface conditions required to obtain a crystalline and preferentially oriented phase have been established. The composition and morphological changes related to the PLT/YSZ/(100InP heterostructure profile have been studied in order to investigate the processes involved in the growth of these oxides on (100InP.Se ha estudiado el proceso de depósito mediante ablación con láser de láminas delgadas de PbTiO3 modificado con La (PLT y ZnO sobre (100InP. Para el PLT se han depositado láminas intermedias de óxidos dieléctricos (CeO2, ZrO2, SrO, YSZ, MgO, y SrTiO3 necesarias para la protección de la superficie del substrato. En cada caso se han establecido las condiciones experimentales (presión de oxígeno, temperatura del substrato, densidad de energía del pulso láser y limpieza de la superficie del substrato necesarias para obtener láminas cristalinas con orientación preferente. En la heteroestructura PLT/YSZ/(100InP se estudian los cambios de composición y morfología a lo largo del perfil de la heteroestructura, a fin de investigar los procesos involucrados en el crecimiento de estos óxidos sobre el (100InP.

  11. Budker INP in ATLAS

    CERN Multimedia

    2001-01-01

    The Novosibirsk group has proposed a new design for the ATLAS liquid argon electromagnetic end-cap calorimeter with a constant thickness of absorber plates. This design has signifi- cant advantages compared to one in the Technical Proposal and it has been accepted by the ATLAS Collaboration. The Novosibirsk group is responsible for the fabrication of the precision aluminium structure for the e.m.end-cap calorimeter.

  12. Volmer–Weber InAs quantum dot formation on InP (113)B substrates under the surfactant effect of Sb

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yu, E-mail: yu.zhao@insa-rennes.fr; Bertru, Nicolas; Folliot, Hervé; Rohel, Tony [Université Européenne de Bretagne, INSA, FOTON, UMR-CNRS 6082, 20 Avenue des Buttes de Coësmes, F-35708 Rennes Cedex 7 (France); Mauger, Samuel J. C.; Koenraad, Paul M. [COBRA Inter-University Research Institute, Eindhoven University of Technology, P.O. Box 513, NL-5600MB Eindhoven (Netherlands)

    2014-07-21

    We report on Sb surfactant growth of InAs nanostructures on GaAs{sub 0.51}Sb{sub 0.49} layers deposited on InP (001) and on (113)B oriented substrates. On the (001) orientation, the presence of Sb significantly favors the two-dimensional growth regime. Even after the deposition of 5 mono-layers of InAs, the epitaxial film remains flat and InAs/GaAs{sub 0.51}Sb{sub 0.49} type-II quantum wells are achieved. On (113)B substrates, same growth runs resulted in formation of high density InAs islands. Microscopic studies show that wetting layer is missing on (113)B substrates, and thus, a Volmer-Weber growth mode is concluded. These different behaviors are attributed to the surface energy changes induced by Sb atoms on surface.

  13. Epitaxial growth of quantum dots on InP for device applications operating at the 1.55 μm wavelength range

    DEFF Research Database (Denmark)

    Semenova, Elizaveta; Kulkova, Irina; Kadkhodazadeh, Shima

    2014-01-01

    The development of epitaxial technology for the fabrication of quantum dot (QD) gain material operating in the 1.55 μm wavelength range is a key requirement for the evolvement of telecommunication. High performance QD material demonstrated on GaAs only covers the wavelength region 1-1.35 μm...... lithography. Due to the lower lattice mismatch of InAs/InP compared to InAs/GaAs, InP based QDs have a larger diameter and are shallower compared to GaAs based dots. This shape causes low carrier localization and small energy level separation which leads to a high threshold current, high temperature...... with the possibility to approach an ideal QD shape....

  14. Particle-based Full-band Approach for Fast Simulation of Charge Transport in Si, GaAs, and InP

    Directory of Open Access Journals (Sweden)

    Marco Saraniti

    2002-01-01

    Full Text Available We discuss the application of the fullband cellular automaton (CA method for the simulation of charge transport in several semiconductors. Basing the selection of the state after scattering on simple look-up tables, the approach is physically equivalent to the full band Monte Carlo (MC approach but is much faster. Furthermore, the structure of the pre-tabulated transition probabilities naturally allows for an extension of the model to fully anisotropic scattering without additional computational burden. Simulation results of transport of electrons and holes in several materials are discussed, with particular emphasis on the transient response of photo-generated carriers in InP and GaAs. Finally, a discussion on parallel algorithms is presented, for the implementation of the code on workstation clusters.

  15. Nanoelectronic devices--resonant tunnelling diodes grown on InP substrates by molecular beam epitaxy with peak to valley current ratio of 17 at room temperature

    Institute of Scientific and Technical Information of China (English)

    Zhang Yang; Zeng Yi-Ping; Ma Long; Wang Bao-Qiang; Zhu Zhan-Ping; Wang Liang-Chen; Yang Fu-Hua

    2006-01-01

    This paper reports that InAs/In0.53Ga0.47As/AlAs resonant tunnelling diodes have been grown on InP substrates by molecular beam epitaxy. Peak to valley current ratio of these devices is 17 at 300K. A peak current density of 3kA/cm2 has been obtained for diodes with AlAs barriers of ten monolayers, and an In0.53Ga0.47As well of eight monolayers with four monolayers of InAs insert layer. The effects of growth interruption for smoothing potential barrier interfaces have been investigated by high resolution transmission electron microscope.

  16. High quality-factor Si/SiO(2)-InP hybrid micropillar cavities with submicrometer diameter for 1.55-μm telecommunication band.

    Science.gov (United States)

    Song, Hai-Zhi; Takemoto, Kazuya; Miyazawa, Toshiyuki; Takatsu, Motomu; Iwamoto, Satoshi; Ekawa, Mitsuru; Yamamoto, Tsuyoshi; Arakawa, Yasuhiko

    2015-06-15

    We theoretically demonstrate high quality(Q)-factor micropillar cavities at 1.55-μm wavelength based on Si/SiO(2)-InP hybrid structure. An adiabatic design in distributed Bragg reflectors (DBRs) improves Q-factor for upto 3 orders of magnitude, while reducing the diameter to sub-micrometer. A moderate Q-factor of ~3000 and a Purcell factor of ~200 are realized by only 2 taper segments and fewer conventional DBR pairs, enabling single photon generation at GHz rate. As the taper segment number is increased, Q-factor can be boosted to ~10(5)-10(6), enabling coherent exchange between the emitter and the optical mode at 1.55 μm, which is applicable in quantum information networks.

  17. Photovoltaic conversion of visible spectrum by GaP capped InP quantum dots grown on Si (100) by metalorganic chemical vapor deposition

    Science.gov (United States)

    Halder, Nripendra N.; Biswas, Pranab; Banerji, P.; Kundu, Souvik; Nagabhushan, B.; Sarkar, Krishnendu; Chowdhury, Sisir; Chaudhuri, Arunava

    2015-01-01

    Growth of GaP capped strained InP quantum dots was carried out by metal organic chemical vapor deposition technique on Si (100) substrates to explore an alternative material system for photovoltaic conversion. Studies on reflectance spectroscopy show higher absorption of visible photons compared to scattering. Smooth and defect free interface provides low dark current with high rectification ratio. A solar cell made of five periods of quantum dots is found to provide a conversion efficiency of 4.18% with an open circuit voltage and short circuit current density of 0.52 V and 13.64 mA/cm2, respectively, under AM 1.5 solar radiation.

  18. Multi-wafer growth of GaInAs photodetectors on 4" InP by MOCVD for SWIR imaging applications

    Science.gov (United States)

    Furlong, Mark J.; Mattingley, Mark; Lim, Sung Wook; Geen, Matthew; Jones, Wynne

    2014-06-01

    Photodiodes based on the GaInAs/InP material system responding in the 1.3-1.7 μm wavelength range are of interest in a wide range of applications, from optical power and channel monitors in telecommunication systems through to advanced night vision imaging using large format focal plane type detectors for defense and security applications. Here we report on our results of GaInAs PIN photo detector structures grown on 2", 3" and 4" InP substrates by low pressure Metalorganic Chemical Vapor Deposition (MOCVD) in both standard and new larger volume format reactor configurations. High quality, lattice matched InP/GaInAs epitaxial layers were grown and we demonstrate that when moving to larger platen configurations, high degree of thickness uniformity (improved performance.

  19. Characterization of the InN conversion layer in InP surface by ammonia gas: Nuclear reaction analysis, X-ray diffraction and Raman scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Mizuki, Y. [College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584 (Japan); Onoue, A. [College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584 (Japan); Kuriyama, K. [College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584 (Japan)]. E-mail: kuri@ionbeam.hosei.ac.jp; Hasegawa, M. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Sakamoto, I. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2006-08-15

    The surface layer of InP(1 0 0) wafer is converted into {alpha}-InN phase (wurtzite) by annealing it at around 510 {sup o}C for 5 h under NH{sub 3} gas flow. X-ray diffraction analysis shows that the conversion layer is a (1 1 -2 0) oriented InN. This result is also supported by E{sub 1}(TO) and A{sub 1}(LO) phonon modes observed by a Raman scattering method, originated from the (1 1 -2 0) face of {alpha}-InN. The converted layer evaluated by nuclear reaction analysis using a {sup 14}N(d, p){sup 15}N reaction includes a N concentration of {approx}6 x 10{sup 22} cm{sup -3}.

  20. [Safety and health in workers employed in industry. Data from Industrial Accidents Compensation Board (INAIL) and National Social Security Institute (INPS), Veneto Region, 1994-2002].

    Science.gov (United States)

    Mastrangelo, G; Carassai, Patrizia; Carletti, Claudia; Cattani, F; De Zorzi, Lia; Di Loreto, G; Dini, M; Mattioni, G; Mundo, Antonietta; Noceta, R; Ortolani, G; Piccioni, M; Sartori, Angela; Sereno, Antonella; Priolo, G; Scoizzato, L; Marangi, G; Marchiori, L

    2008-01-01

    A decreasing time trend for occupational injuries and sickness absence would be the effect of the new legislation (D.Lgs. 626/94 and successive laws) on prevention in occupational settings. Conversely, the reduction of INPS disability would reflect a health improvement due to non-occupational causes. The aim of the study was to investigate the efficacy of the new legislation among employees in industry (where the law was mainly applied), via the time trend of three standardized rates in the Veneto Region. The numerator for the rate of occupational accidents (cases occurring in industry workers in the Veneto Region, broken down for sex, age and calendar years) was supplied by INAIL. The denominator for the above rate, as well as numerators and denominators for disability and sickness absence were supplied by INPS. Data were available from 1994 to 2002 for accidents and disability, and from 1997 to 2002 for sickness absence. In every year from 1994 to 2002, the rates were standardized for age and sex with the direct method, using an internal "standard" population. The time trend of year-specific standardized rates was analyzed by Joinpoint regression software. Among industrial workers in the Veneto Region, occupational accidents increased by 0.4% yearly, while disability decreased by 2.56% from 1994 to 2002. Sick absence increased up to 1999, then decreased. This epidemiological pattern is difficult to explain. The increase in accidents could be due to the increase of non-European Union workers and/or to the fact that accidents on the way to or from work were recognized as occupational accidents by INAIL starting from 2000. Both these phenomena could have contributed to increase the rate that was otherwise diminishing. On the other hand, this same situation could be due to insufficient efficacy of the legislation (D.Lgs. 626/94 and successive laws) for preventing occupational accidents and diseases.

  1. Optimization of the short-circuit current in an InP nanowire array solar cell through opto-electronic modeling.

    Science.gov (United States)

    Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

    2016-09-23

    InP nanowire arrays with axial p-i-n junctions are promising devices for next-generation photovoltaics, with a demonstrated efficiency of 13.8%. However, the short-circuit current in such arrays does not match their absorption performance. Here, through combined optical and electrical modeling, we study how the absorption of photons and separation of the resulting photogenerated electron-hole pairs define and limit the short-circuit current in the nanowires. We identify how photogenerated minority carriers in the top n segment (i.e. holes) diffuse to the ohmic top contact where they recombine without contributing to the short-circuit current. In our modeling, such contact recombination can lead to a 60% drop in the short-circuit current. To hinder such hole diffusion, we include a gradient doping profile in the n segment to create a front surface barrier. This approach leads to a modest 5% increase in the short-circuit current, limited by Auger recombination with increased doping. A more efficient approach is to switch the n segment to a material with a higher band gap, like GaP. Then, a much smaller number of holes is photogenerated in the n segment, strongly limiting the amount that can diffuse and disappear into the top contact. For a 500 nm long top segment, the GaP approach leads to a 50% higher short-circuit current than with an InP top segment. Such a long top segment could facilitate the fabrication and contacting of nanowire array solar cells. Such design schemes for managing minority carriers could open the door to higher performance in single- and multi-junction nanowire-based solar cells.

  2. Optimization of the short-circuit current in an InP nanowire array solar cell through opto-electronic modeling

    Science.gov (United States)

    Chen, Yang; Kivisaari, Pyry; Pistol, Mats-Erik; Anttu, Nicklas

    2016-10-01

    InP nanowire arrays with axial p-i-n junctions are promising devices for next-generation photovoltaics, with a demonstrated efficiency of 13.8%. However, the short-circuit current in such arrays does not match their absorption performance. Here, through combined optical and electrical modeling, we study how the absorption of photons and separation of the resulting photogenerated electron-hole pairs define and limit the short-circuit current in the nanowires. We identify how photogenerated minority carriers in the top n segment (i.e. holes) diffuse to the ohmic top contact where they recombine without contributing to the short-circuit current. In our modeling, such contact recombination can lead to a 60% drop in the short-circuit current. To hinder such hole diffusion, we include a gradient doping profile in the n segment to create a front surface barrier. This approach leads to a modest 5% increase in the short-circuit current, limited by Auger recombination with increased doping. A more efficient approach is to switch the n segment to a material with a higher band gap, like GaP. Then, a much smaller number of holes is photogenerated in the n segment, strongly limiting the amount that can diffuse and disappear into the top contact. For a 500 nm long top segment, the GaP approach leads to a 50% higher short-circuit current than with an InP top segment. Such a long top segment could facilitate the fabrication and contacting of nanowire array solar cells. Such design schemes for managing minority carriers could open the door to higher performance in single- and multi-junction nanowire-based solar cells.

  3. Investigations on the influence of Peltier effect and electromigration during growth of InP, InGaP and InAsP by liquid phase electro-epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Fareed, R.S.Q.; Dhanasekaren, R. [Anna Univ., Madras (India). Crystal Growth Centre

    1996-12-31

    In the present communication, a model has been developed to understand the growth mechanism of InP, InGaP and InAsP semiconductors. The model is based on the diffusion and electromigration of the solute atoms. During Peltier cooling conditions, growth occurs. When the direction of the electric field is reversed, dissolution of solute atoms is observed due to Peltier heating at the interface. Computer simulation technique has been employed to construct the concentration profiles of the solute atoms in the immediate vicinity of the growing interface in the In rich melt during the growth of InP. It is observed that the concentration of the solute atoms decreases with time near the substrate-solution interface as the growth proceeds and there is increase in the concentration of the solute atoms during Peltier heating. Profiles of the solute atoms under various growth conditions such as different applied electric field, change in interface temperature, etc.

  4. Improved interface properties of atomic-layer-deposited HfO{sub 2} film on InP using interface sulfur passivation with H{sub 2}S pre-deposition annealing

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyun Soo [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Cho, Young Jin [Inorganic Material Lab., Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Department of Materials Science & Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-742 (Korea, Republic of); Seok, Tae Jun; Kim, Dae Hyun; Kim, Dae Woong [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Sang-Moon [Process Development Team, Semiconductor R& D Center, Samsung Electronics Co. Ltd, Hwasung 445-701 (Korea, Republic of); Park, Jong-Bong; Yun, Dong-Jin [Analytical Engineering Group, Platform Technology Lab., Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Kim, Seong Keun [Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Hwang, Cheol Seong, E-mail: cheolsh@snu.ac.kr [Department of Materials Science & Engineering and Inter-university Semiconductor Research Center, Seoul National University, Seoul 151-742 (Korea, Republic of); Park, Tae Joo, E-mail: tjp@hanyang.ac.kr [Department of Materials Science & Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of)

    2015-12-01

    Highlights: • ALD HfO{sub 2} films were grown on InP for III–V compound-semiconductor-based devices. • S passivation was performed with (NH{sub 4}){sub 2}S solution and annealing under a H{sub 2}S atmosphere. • The H{sub 2}S annealing provided similar S profiles at the interface without surface damage. • The H{sub 2}S annealing was more effective to suppress interface state density due to thermal energy. - Abstract: Surface sulfur (S) passivation on InP substrate was performed using a dry process – rapid thermal annealing under H{sub 2}S atmosphere for III–V compound-semiconductor-based devices. The electrical properties of metal-oxide-semiconductor capacitor fabricated with atomic-layer-deposited HfO{sub 2} film as a gate insulator were examined, and were compared with the similar devices with S passivation using a wet process – (NH{sub 4}){sub 2}S solution treatment. The H{sub 2}S annealing provided solid S passivation with the strong resistance against oxidation compared with the (NH{sub 4}){sub 2}S solution treatment, although S profiles at the interface of HfO{sub 2}/InP were similar. The decrease in electrical thickness of the gate insulator by S passivation was similar for both methods. However, the H{sub 2}S annealing was more effective to suppress interface state density near the valence band edge, because thermal energy during the annealing resulted in stronger S bonding and InP surface reconstruction. Moreover, the flatband voltage shift by constant voltage stress was lower for the device with H{sub 2}S annealing.

  5. The start-up phase of the national satellite forest monitoring systems for DRC and PNG: a joint venture between FAO and INPE

    Science.gov (United States)

    Jonckheere, I. G.; FAO UN-REDD Team Forestry Department

    2011-12-01

    Reducing Emissions from Deforestation and Forest Degradation (REDD) is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. "REDD+" goes beyond deforestation and forest degradation, and includes the role of conservation, sustainable management of forests and enhancement of forest carbon stocks. In the framework of getting countries ready for REDD+, the UN-REDD Programme, a partnership between UNEP, FAO and UNDP, assists developing countries to prepare and implement national REDD+ strategies. Designed collaboratively by a broad range of stakeholders, national UN-REDD Programmes are informed by the technical expertise of FAO, UNDP and UNEP. For the monitoring, reporting and verification, FAO supports the countries to develop satellite forest monitoring systems that allow for credible measurement, reporting and verification (MRV)of REDD+ activities. These are among the most critical elements for the successful implementation of any REDD+ mechanism, also following the COP 16 decisions in Cancun last year. The UN-REDD Programme through a joint effort of FAO and Brazil's National Space Agency, INPE, is supporting countries to develop cost-effective, robust and compatible national monitoring and MRV systems, providing tools, methodologies, training and knowledge sharing that help countries to strengthen their technical and institutional capacity for effective MRV systems. To develop strong nationally-owned forest monitoring systems, technical and institutional capacity building is key. The UN-REDD Programme, through FAO, has taken on intensive training together with INPE, and has provided technical help and assistance for in-country training and implementation for national satellite forest monitoring. The goal of the start-up phase for DRC and Papua New Guinea (PNG) in this capacity building effort is the

  6. Analisys, processing and validation data from eolic stations of SONDA project (National Organization System of Environmental Data) at Brazilian National Institute for Space Research (CPTEC/INPE) .

    Science.gov (United States)

    Junior, A. B.; Nogueira, J. M.; Garcia, S. G.; Andrade, E. S.

    2007-05-01

    Asiel Bomfin Jr. LIM/CPTEC/INPE, Cachoeira Paulista, S.P., Brazil; Eliana Soares de Andrade; Jorge Luiz Martins Nogueira and Silvia Garcia de Castro. The Center for Weather Forecast and Climatic Analysis (CPTEC), a division of INPE, the Brazilian National Institute for Space Research. Several of the INPE´s departments and centers, like the CPTEC, have a variety of valuable datasets, many of them freely available and eolic data from SONDA project are also part of them at Meteorological Instrumental Laboratory (LIM). This paper presents the Analiys, processing and validation method applied to the eolic data in a temporal time of ten minutes, to be used in a PC IBM computer. This method is divided in tree separated programs. The first software called "separa.c" has the capability of divide the ingest data set in mensal files, identified by each station group. The second software called "minuto.c" does a syntactical analysis, verifying and correcting eventual lost data with NAN values. The third one called "validacode.c" generates two principal files, one containing the original data and the other with the codes of each variable for each minute analyzed. These codes is based on BSRN (Baseline Surface Radiation Network), but with some differences in their analyzed method. This method followed the Webmet.com, The Meteorological Resource Center. Table 1:Validation Codes Code Meaning 0 Quality check procedure is not avaiable for this level 2 The data is suspect 5 Quality check procedure is avaiable for this level, but not can be done 9 The data is correct Table 2: Validation levels for WIND SPEED: Validation Levels Quality check procedure for suspect data 0 Maximum and Minimum values of 25 m/s and 0 m/s 1 Can not vary more than 0,1 m/s for 03 consecutive hours 2 Can not vary more than 0,5 m/s for 12 consecutive hours 3 - Table 3: Validation levels for WIND DRECTION: Validation Levels Quality check procedure for suspect data 0 Maximum and Minimum values of 360 and 0

  7. Simulation of the impacts land use and land cover changes - LUCC on the hydrological response of the Ji-Parana Basin with MGB-INPE model

    Science.gov (United States)

    Rodriguez, D. A.; Tomasella, J.

    2012-04-01

    Hydrological response results from innumerous processes interacting at different spatial and temporal scales and with various intensities. Since the hydrological impacts of Land use and land cover change (LUCC) and climate variability (CV) are strongly dependent on soil water flow pathways, an adequate representation of the runoff generation mechanisms are crucial to assess the hydrological impacts of LUCC and CV on a basin scale. Model responses to LUCC depend on structure and parameterizations used in the model. There are two basic methodologies adopted to define the structure of the hydrological model: downward and upward approaches. Upward approach is more appropriate for identifying causal relationships, but their results are highly affected by assumptions used in the development of the model. Besides, model structure and parameters values definition are strongly affected by scale issues and their inter-relationships. Downward approach is more appropriate for studying the effects of LUCC, but casual relationships are more difficult to identify. MGB-INPE model was developed based on the Large Scale Basins Model of Brazilian Institute of Hydraulic Research (MGB-IPH). It uses the Xinanjiang Model approach for soil water capacity distribution at each cell combined with TopModel philosophy. Both methodologies follow a downward approach: the hydrologic response of the basin is associated with patterns of self-organization observed at the basin-scale. The model was applied in the Ji-Parana Basin (JPB), a 30.000-km2 basin in the SW Amazonia. The JPB is part of the Deforestation Arc of Amazonia in Brazil and it has lost more than 50 % of his forest cover since the 80's. Simulations were performed between 1982 and 2005 considering annual land use and land cover change. MGB-INPE model was able to represent the impact of LUCC in the runoff generation process and its dependence with basin topography. Simulation results agree with observational studies: LUCC impacts in fast

  8. Effect of band alignment on photoluminescence and carrier escape from InP surface quantum dots grown by metalorganic chemical vapor deposition on Si

    Science.gov (United States)

    Halder, Nripendra N.; Biswas, Pranab; Dhabal Das, Tushar; Das, Sanat Kr.; Chattopadhyay, S.; Biswas, D.; Banerji, P.

    2014-01-01

    A detailed analysis of photoluminescence (PL) from InP quantum dots (QDs) grown on Si has been carried out to understand the effect of substrate/host material in the luminescence and carrier escape process from the surface quantum dots. Such studies are required for the development of monolithically integrated next generation III-V QD based optoelectronics with fully developed Si microelectronics. The samples were grown by atmospheric pressure metalorganic chemical vapor deposition technique, and the PL measurements were made in the temperature range 10-80 K. The distribution of the dot diameter as well as the dot height has been investigated from atomic force microscopy. The origin of the photoluminescence has been explained theoretically. The band alignment of InP/Si heterostructure has been determined, and it is found be type II in nature. The positions of the conduction band minimum of Si and the 1st excited state in the conduction band of InP QDs have been estimated to understand the carrier escape phenomenon. A blue shift with a temperature co-efficient of 0.19 meV/K of the PL emission peak has been found as a result of competitive effect of different physical processes like quantum confinement, strain, and surface states. The corresponding effect of blue shift by quantum confinement and strain as well as the red shift by the surface states in the PL peaks has been studied. The origin of the luminescence in this heterojunction is found to be due to the recombination of free excitons, bound excitons, and a transition from the 1st electron excited state in the conduction band (e1) to the heavy hole band (hh1). Monotonic decrease in the PL intensity due to increase of thermally escaped carriers with temperature has been observed. The change in barrier height by the photogenerated electric-field enhanced the capture of the carriers by the surface states rather than their accumulation in the QD excited state. From an analysis of the dependence of the PL intensity

  9. Band offsets and electronic structures of interface between In{sub 0.5}Ga{sub 0.5}As and InP

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Genwang [School of Physical Science and Engineering and Key Laboratory of Materials Physics of Ministry of Education of China, Zhengzhou University, Zhengzhou 450052 (China); College of Science, Henan University of Technology, Zhengzhou 450001 (China); Wang, Changhong; Wang, Weichao [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Liang, Erjun, E-mail: ejliang@zzu.edu.cn [School of Physical Science and Engineering and Key Laboratory of Materials Physics of Ministry of Education of China, Zhengzhou University, Zhengzhou 450052 (China)

    2016-02-07

    III–V semiconductor interfacing with high-κ gate oxide is crucial for the high mobility metal-oxide-semiconductor field transistor device. With density functional theory calculations, we explored the band offsets and electronic structures of the In{sub 0.5}Ga{sub 0.5}As/InP interfaces with various interfacial bondings. Among six different bonding interfaces, we found that P-In(Ga) bonding interface showed the highest stability. Local density of states calculations was adopted to calculate the band offsets. Except for the metallic interface, we noticed that neither valence band offset nor conduction band offset depended on the interfacial bondings. For the most stable P-In(Ga) interface, we did not observe any gap states. Furthermore, we explored the P-In(Ga) interfaces with interfacial P-As exchange defects, which slightly modified the interface stability and the band offsets but did not produce any gap states. These findings provide solid evidence that InP could serve as a promising interfacial passivation layer between III–V material and high-κ oxide in the application of high mobility devices.

  10. Effect of band offset on carrier transport and infrared detection in InP quantum dots/Si nano-heterojunction grown by metalorganic chemical vapor deposition technique

    Science.gov (United States)

    Halder, Nripendra N.; Biswas, Pranab; Nagabhushan, B.; Kundu, Souvik; Biswas, D.; Banerji, P.

    2014-05-01

    Epitaxy of III-V semiconductors on Si gets recent interest for next generation system on heterogeneous chip on wafer. The understanding of band offset is thus necessary for describing the charge transport phenomenon in these heterojunctions. In this work, x-ray photoemission spectroscopy has been used to determine the band offsets in a heterojunction made of InP quantum dots on Si. The valence and conduction band offset was found to be 0.12 eV and 0.35 eV, respectively, with a type-II band lineup. Deviation from theoretical prediction and previously published reports on quasi similar systems have been found and analyzed on the basis of the effect of strain, surface energy, shift in the electrostatic dipole and charge transfer at the interface. The carrier transport mechanisms along with different device parameters in the heterojunction have been studied for a temperature range of 180-300 K. This heterojunction is found to behave as an efficient infrared photodetector with an ON/OFF ratio of 21 at a reverse bias of 2 V. The corresponding rise and decay time was found to be 132 ms and 147 ms, respectively.

  11. Binding of electrons, holes, and excitons in symmetric strained InP/ In0.49 Ga0.51 P triple quantum-dot molecules

    Science.gov (United States)

    Tadić, M.; Peeters, F. M.

    2004-11-01

    The electron, hole, and exciton spectra in the strained quantum-dot molecule consisting of three vertically arranged type-II InP/ In0.49 Ga0.51 P self-assembled quantum dots are modeled by the k•p theory. For the sake of simplicity, we consider dots of cylindrical shape, but take into account the anisotropy of the strain through the continuum mechanical model. For thick spacers, the strain leads to an upward shift of the lowest energies in all explored electron shells, but for spacers thinner than, say, the coupling length, the quantum mechanical coupling prevails, and downward shifts are observed. The magnitudes of both the energy shift and the coupling length vary with the quantum-dot height. For the holes, the interplay of strain and mixing enables binding at larger distances than for the electrons. The overlap of the hole clouds is basically established by means of the light holes, which are confined by the strain in the spacer between the dots and may efficiently couple the heavy-hole states, which are localized inside the quantum dots. Similar to electrons, the exciton lowest-energy states of different angular momenta, as computed by an exact-diagonalization approach, exhibit overshoots on the single-quantum-dot levels. Good agreement is found with experiment on the spatial location of electrons and holes in the triple-quantum-dot molecules.

  12. Magnesium doping in InAlAs and InGaAs/Mg films lattice-matched to InP grown by MOVPE

    Science.gov (United States)

    Ezzedini, Maher; Sfaxi, Larbi; M'Ghaieth, Ridha

    2017-01-01

    Mg-doped InAlAs and InGaAs films were grown at 560 °C lattice matched to InP semi-insulting substrate by metalorganic vapor phase epitaxy (MOVPE) under various Cp2Mg flow conditions. Hall effect, photoluminescence (PL), high-resolution X-ray diffraction (HR-XRD), and secondary ion mass (SIMS) were the tools used in this work. The crystalline quality and the n-p conversion of the InAlAs and InGaAs/Mg films are described and discussed in relation to the Cp2Mg flow. Distinguishing triple emission peaks in PL spectra is observed and seems to be strongly dependent on the Cp2Mg flow. SIMS is employed to analyze the elements in the epitaxial layers. The variation of indium and magnesium components indicates a decrease of magnesium incorporation during the growth of InAlAs layers leading to a contracted lattice. In addition, the magnesium incorporation in the InGaAs lattice during growth has been confirmed by SIMS.

  13. Projected Range, Straggling and Sputtering Yield of the Ion-Impingement of Inert Gases in Group IV, InP and GaAs Semiconductors

    Directory of Open Access Journals (Sweden)

    J.D. Femi-Oyetoro

    2015-03-01

    Full Text Available One of the major challenges in ion implantation and sputtering process (especially in thin film deposition is to get a shallow or very deep profile and maximum sputtering yield respectively. In this paper, we simulate the projected range, lateral straggle, longitudinal straggle and sputtering yield of inert gas ions (He+, Ne+, Ar+, Kr+, Xe+, Rn+ impinged in group IV elements (C, Si, Ge, Sn, Pb, InP and GaAs against different parameters (ion energy and angle of incident ion, using the TRIM Monte-Carlo Code as embedded in SRIM. In particular, we generated a result on the consistency of the projected range, lateral and longitudinal straggle with the angle of incident ion using ion energies 1 KeV and 10 KeV. However an inconsistency exists in the sputtering yield and we noticed that maximum sputtering yield occurs for certain incident angle. In conclusion, the results presented here provides parameters needed to get low or high projected range and straggling, and also the exact incident angle needed in getting the maximum sputtering yield for the ion-target combinations used.

  14. High electron density and mobility in single and double planar doped InGaAs/InAlAs heterojunctions in InP

    Energy Technology Data Exchange (ETDEWEB)

    Gueissaz, F.; Houdre, R.; Ilegems, M. (Inst. de Micro- et Optoelectronique, Ecole Polytechnique Federale de Lausanne (Switzerland))

    1991-05-01

    We present results of a growth study concerning the electrical properties of lattice matched InAlGa/InGaAs single planar doped (SPD) and double planar doped (DPD) heterostructures grwon on InP by molecular beam epitaxy (MBE). It is shown that room temperature electron mobilities ({mu}{sub H}) as high as 11000 cm{sup 2}/V.s at high sheet densities of 2.8x10{sup 12} cm{sup -2} can be obtained by optimizing the growth temperatures of each material in the SPD structure. High performance two-dimensional electron gas field effect transistors (TEGFET's) are demonstrated, with transconductances as high as 420 mS/mm at 1 {mu}m gatelength and f{sub T}'s of 46 GHz at 0.7 {mu}m gatelength. The DPD heterostructures further boost the n{sub s} values up to 6.2x10{sup 12} cm{sup -2} at {mu}{sub H} (300 K)=6000 cm{sup 2}/V.s. (orig.).

  15. MBE Growth of High Electron Mobility InP Epilayers%高电子迁移率InP/InP外延材料的MBE生长

    Institute of Scientific and Technical Information of China (English)

    舒永春; 姚江宏; 林耀望; 邢小东; 皮彪; 徐波; 王占国; 许京军

    2005-01-01

    The molecular beam epitaxial growth of high quality epilayers on (100) InP substrate using a valve phosphorous cracker cell over a wide range of P/In BEP ratio (2.0~7.0) and growth rate (0. 437 and 0. 791μm/h). Experimental results show that electrical properties exhibit a pronounced dependence on growth parameters, which are growth rate, P/In BEP ratio, cracker zone temperature, and growth temperature. The parameters have been optimized and electron concentration of 1.55 × 1015 cm-3 have been achieved with an epilayer thickness of 2.35μtm at a growth temperature of 370℃ by using a cracking zone temperature of 850℃.%采用固态磷源分子束外延技术在InP(100)衬底上生长了高质量的InP外延材料.实验结果表明InP/InP外延材料的电学性质与诸多生长参数密切相关.根据霍耳测量结果,对生长条件和实验参数进行了优化,在生长温度为370℃,磷裂解温度为850℃,生长速率为0.791μm/h和束流比为2.5的条件下,获得了厚度为2.35μm的InP/InP外延材料.在77K温度下,电子浓度为1.55×1015cm-3,电子迁移率达到4.57×104cm2/(V·s).

  16. Impacto de perfis de rádio ocultação GNSS na qualidade das Previsões de tempo do CPTEC/INPE

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Sapucci

    2014-12-01

    Full Text Available Estudos sobre a sensibilidade dos modelos de previsão numérica de tempo a erros nas condições iniciais têm evidenciado a contribuição da assimilação de dados na melhoria do desempenho dos mesmos em descrever o estado futuro da atmosfera. Entre outras fontes de dados, a assimilação de perfis atmosféricos obtidos por rádio ocultação Global Navigation Satellite System (GNSS tem-se destacado como uma ferramenta adicional na redução das deficiências do sistema de coleta de dados meteorológicos. Com o intuito de explorar os benefícios dessa fonte adicional de dados na previsão numérica de tempo gerada pelo modelo de circulação geral atmosférico do CPTEC/INPE, foram realizados experimentos assimilando perfis atmosféricos de altura geopotencial e umidade obtidos por rádio ocultação GNSS, utilizando dados da constelação Constellation Observing System for Meteorology Ionosphere & Climate (COSMIC, para os meses de janeiro e julho de 2009. Os resultados mostraram que o impacto é significativamente positivo durante o verão em todas as variáveis de estado, com ganhos expressivos na extensão das previsões válidas (coeficiente de correlação de anomalia acima de 60%, os quais foram em alguns casos superiores a 48 horas. Esse impacto foi ainda maior sobre a América do Sul com resultados positivos mesmo durante o inverno.

  17. The mechanism of twinning in zincblende structure crystals: New insights on polarity effects from a study of magnetic liquid encapsulated Czochralski grown InP single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dudley, M.; Raghothamachar, B.; Guo, Y. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering] [and others

    1998-12-31

    Synchrotron White Beam X-ray Topography (SWBXT) and synchrotron X-ray anomalous scattering have been employed to determine the polarity of {l_brace}111{r_brace} edge facets, anchored to the three phase boundary (TPB) on which twinning is observed to nucleate in Magnetic Liquid Encapsulated Czochralski (MLEC) grown sulfur doped, <001> InP single crystals. Analysis of the results indicates that both the formation of edge facets and the nucleation of twins occur preferentially on {l_brace}{bar 1}{bar 1}{bar 1}{r_brace}{sub P} faces. Of the four possible sets of edge facets, belonging to the {l_brace}{bar 1}{bar 1}{bar 1}{r_brace}{sub P} form, which are oriented so as to be thermodynamically favored to be anchored to the TPB, two can give rise to a {l_brace}115{r_brace} to {l_brace}{bar 1}{bar 1}{bar 1}{r_brace}{sub P} external should facet conversion upon twinning, while the other two can give rise to a {l_brace}114{r_brace} to {l_brace}110{r_brace} conversion. For these cases, twinning is only observed when the {l_brace}{bar 1}{bar 1}{bar 1}{r_brace}{sub P} edge facets are anchored to the TPB in a region where the shoulder angle is close to 74.21{degree} or 70.53{degree}, facilitating the production of the {l_brace}115{r_brace} and {l_brace}114{r_brace} external should facets, respectively, prior to twinning. These observations are discussed in light of calculated surface energies of the various internal and external facets.

  18. All-optical SR flip-flop based on SOA-MZI switches monolithically integrated on a generic InP platform

    Science.gov (United States)

    Pitris, St.; Vagionas, Ch.; Kanellos, G. T.; Kisacik, R.; Tekin, T.; Broeke, R.; Pleros, N.

    2016-03-01

    At the dawning of the exaflop era, High Performance Computers are foreseen to exploit integrated all-optical elements, to overcome the speed limitations imposed by electronic counterparts. Drawing from the well-known Memory Wall limitation, imposing a performance gap between processor and memory speeds, research has focused on developing ultra-fast latching devices and all-optical memory elements capable of delivering buffering and switching functionalities at unprecedented bit-rates. Following the master-slave configuration of electronic Flip-Flops, coupled SOA-MZI based switches have been theoretically investigated to exceed 40 Gb/s operation, provided a short coupling waveguide. However, this flip-flop architecture has been only hybridly integrated with silica-on-silicon integration technology exhibiting a total footprint of 45x12 mm2 and intra-Flip-Flop coupling waveguide of 2.5cm, limited at 5 Gb/s operation. Monolithic integration offers the possibility to fabricate multiple active and passive photonic components on a single chip at a close proximity towards, bearing promises for fast all-optical memories. Here, we present for the first time a monolithically integrated all-optical SR Flip-Flop with coupled master-slave SOA-MZI switches. The photonic chip is integrated on a 6x2 mm2 die as a part of a multi-project wafer run using library based components of a generic InP platform, fiber-pigtailed and fully packaged on a temperature controlled ceramic submount module with electrical contacts. The intra Flip-Flop coupling waveguide is 5 mm long, reducing the total footprint by two orders of magnitude. Successful flip flop functionality is evaluated at 10 Gb/s with clear open eye diagram, achieving error free operation with a power penalty of 4dB.

  19. Liderazgo carismático como motivación intrínseca y el desempeño directivo en el INPE Santa Mónica Chorrillos - Lima - 2013

    OpenAIRE

    Gamarra Espíritu, Lidia Patricia

    2015-01-01

    El trabajo Liderazgo carismático como motivación intrinseca y el desempeño directivo en el INPE Santa Mónica Chorrillos -Lima-2013, el cual fue desarrollado con la finalidad de comprobar el efecto del liderazgo carismático en el desempeño directivo. El tipo de diseño fue el cuasi-experimental, pues se manipuló la variable liderazgo carismático, para ver su efecto y relación con la variable, desempeño directivo. La población y muestra estuvo constituida por el director general, personal direct...

  20. Extrinsic and intrinsic regulation of DOR/TP53INP2 expression in mice: effects of dietary fat content, tissue type and sex in adipose and muscle tissues.

    Science.gov (United States)

    Fromm-Dornieden, Carolin; Lytovchenko, Oleksandr; von der Heyde, Silvia; Behnke, Nina; Hogl, Sebastian; Berghoff, Janina; Köpper, Frederik; Opitz, Lennart; Renne, Ulla; Hoeflich, Andreas; Beissbarth, Tim; Brenig, Bertram; Baumgartner, Bernhard G

    2012-09-21

    DOR/TP53INP2 acts both at the chromosomal level as a nuclear co-factor e.g. for the thyroid hormone receptor and at the extrachromosomal level as an organizing factor of the autophagosome. In a previous study, DOR was shown to be down-regulated in skeletal muscle of obese diabetic Zucker fa/fa rats. To identify sites of differential DOR expression in metabolically active tissues, we measured differences in DOR expression in white adipose tissue (WAT), brown adipose tissue (BAT), skeletal muscle (SM) and heart muscle (HM) by qPCR. To assess whether DOR expression is influenced in the short term by nutritional factors, NMRI mice were fed different fat rich diets (fat diet, FD: 18% or high fat diet, HFD: 80% fat) for one week and DOR expression was compared to NMRI mice fed a control diet (normal diet, ND: 3.3% fat). Additionally, DOR expression was measured in young (45 days old) and adult (100 days old) genetically obese (DU6/DU6i) mice and compared to control (DUKs/DUKsi) animals. ANOVA results demonstrate a significant influence of diet, tissue type and sex on DOR expression in adipose and muscle tissues of FD and HFD mice. In SM, DOR expression was higher in HFD than in FD male mice. In WAT, DOR expression was increased compared to BAT in male FD and HFD mice. In contrast, expression levels in female mice were higher in BAT for both dietary conditions.DOR expression levels in all tissues of 100 days old genetically obese animals were mainly influenced by sex. In HM, DOR expression was higher in male than female animals. DOR expression varies under the influence of dietary fat content, tissue type and sex. We identified target tissues for further studies to analyze the specific function of DOR in obesity. DOR might be part of a defense mechanism against fat storage in high fat diets or obesity.

  1. Cytotoxicity assessment of functionalized CdSe, CdTe and InP quantum dots in two human cancer cell models

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing [Institute of Gerontology and Geriatrics & Beijing Key Lab of Aging and Geriatrics, Chinese PLA General Hospital, Beijing 100853 (China); Hu, Rui [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Liu, Jianwei [Institute of Gerontology and Geriatrics & Beijing Key Lab of Aging and Geriatrics, Chinese PLA General Hospital, Beijing 100853 (China); Zhang, Butian; Wang, Yucheng [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Liu, Xin [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Law, Wing-Cheung [Department of Industrial and System Engineering, The Hang Kong Polytechnic University, Hung Hom (Hong Kong); Liu, Liwei [School of Science, Changchun University of Science and Technology, Changchun 130022 (China); Ye, Ling, E-mail: lye_301@163.com [Institute of Gerontology and Geriatrics & Beijing Key Lab of Aging and Geriatrics, Chinese PLA General Hospital, Beijing 100853 (China); Yong, Ken-Tye, E-mail: ktyong@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2015-12-01

    protocols are urgently needed to be developed and employed for fully assessing and understanding the origins of the toxicity arising from different QD formulations. - Highlights: • The cytotoxicity of CdSe, CdTe and InP based on four QD formulations were assessed. • Gastric adenocarcinoma and neuroblastoma cells showed different toxicity responses. • Multi-factors including core, coating and cell type contribute to QD cytotoxicity. • The cellular uptake of QDs plays an important role in the toxicity impact of QDs.

  2. InP单晶的磁光和热电效应%Magneto-Optical and Seebeck Effect of InP Single Crystal

    Institute of Scientific and Technical Information of China (English)

    潘静; 李晓岚; 杨瑞霞; 孙聂枫

    2011-01-01

    The physical properties were measured for the undoped InP using the temperature control multi purpose cryostat. The temperature dependent photoconductivity measurement was investigated.The room temperature energy gap was 1. 339 2 eV and it's temperature coefficient was found to be -3 × 10-4 eV/K in the range of 295 -318 K . The magneto-optical properties were measured up to 1.8 T,the magnetic coefficient of Eg is 8.6 × 10-4 eV/T. From this value, the reduced effective mass of electrons mr * was found to be 0. 067 m0. From thermoelectric power measurements, Seebeck coefficient was found to be 565 μV/K at room temperature. The density of state effective mass md * was calculated and found to be 0. 075 7m0 according to seebeck coefficient and the Hall measurement value. This value and that of the reduced effective mass of electrons mentioned above gave the effective mass of electrons in the valance band mv * of 0. 591 mO in this lnP sample.%对同一原生非掺杂InP单晶进行了一系列物理测试分析,研究了材料的光电导率与温度的依从关系,在295~318 K内,温度系数为-3×104 eV/K,测得的室温禁带宽度为1.339 2 eV.禁带宽度Eg的磁性系数为8.6×10-4eV/T,材料的磁光特性测量结果为1.8 T.由此数据可得,约化电子有效质量mr*为0.067m0.由热电功率测量结果可得室温塞贝克系数为565 μV/K.由此值以及霍尔测量值,可计算出状态密度有效质量md为0.075 7m0.由该值和上面提到的约化电子有效质量可得到InP样品的价带电子有效质量mv*为0.591m0.

  3. Characterization of InGaAs and InAlAs layers on InP by four-crystal high resolution X-ray diffraction and wedge transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Houdre, R.; Gueissaz, F.; Gailhanou, M.; Ganiere, J.D.; Rudra, A.; Ilegems, M. (Inst. de Micro- et Optoelectronique, Ecole Polytechnique Federale de Lausanne (Switzerland))

    1991-05-01

    The indium desorption rates from InGaAs and InAlAs grown on InP substrates have been measured by wedge transmission electron microscopy as a function of the growth temperature. Desorption becomes significant at 545degC for both materials. No automatching effects could be observed under the growth conditions of the experiment. The bandgap of In{sub y}Al{sub 1-y}As has been measured at 77 K as a function of the indium content. The composition and the strain have been measured by four-crystal high resolution X-ray diffraction with symmetrical (004) and assymmetrical (115{+-}) Bragg reflections. The intrinsic bandgap follows the relation E{sub g}(y)=2.774-2.411y and the strained material the relation E{sub gs}(y)=0.671+5.236y-6.929y{sup 2}. (orig.).

  4. Numerical simulation of the influence of the orbiters attitude on the μg growth of InP : S crystals from an In solution during the EURECA-1 flight

    Science.gov (United States)

    Boschert, St.; Danilewsky, A. N.; Benz, K. W.

    1999-08-01

    S-doped InP crystals were grown from an In-solution in a THM arrangement during the EURECA-1 mission using the automatic mirror furnace (AMF) under microgravity conditions. The InP-crystals showed growth rate oscillations in the range of 0.8-2.0 μm/min with a period of 45 min, which is half the time of an orbit of the EURECA-1 satellite. The fluid dynamic conditions during this experiment are modelled using a 3D model with the commercial software FIDAP. The time-dependent simulation, considering thermal as well as solutal buoyancy effects, indicates a weak laminar flow in this material system. Due to the fixed attitude of the satellite with respect to the sun the residual gravity vector rotates relative to the sample axis. This rotation results in a significant change of the residual convection level. Its maximum is obtained, when the gravity is parallel to the growth interface (two times during each orbit). Due to a high Schmidt number Sc≈25 a time-dependent influence of the convection on the concentration field can also be observed.

  5. Extended wavelength mid-infrared photoluminescence from type-I InAsN and InGaAsN dilute nitride quantum wells grown on InP

    Energy Technology Data Exchange (ETDEWEB)

    Wheatley, R.; Kesaria, M., E-mail: m.kesaria@lancaster.ac.uk; Marshall, A.; Zhuang, Q. D.; Krier, A. [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Mawst, L. J.; Kirch, J. D. [Department of Electrical and Computer Engineering, University of Wisconsin, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States); Kuech, T. F. [Department of Chemical and Biological Engineering, University of Wisconsin, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

    2015-06-08

    Extended wavelength photoluminescence emission within the technologically important 2–5 μm spectral range has been demonstrated from InAs{sub 1−x}N{sub x} and In{sub 1−y}Ga{sub y}As{sub 1−x}N{sub x} type I quantum wells grown onto InP. Samples containing N ∼ 1% and 2% exhibited 4 K photoluminescence emission at 2.0 and 2.7 μm, respectively. The emission wavelength was extended out to 2.9 μm (3.3 μm at 300 K) using a metamorphic buffer layer to accommodate the lattice mismatch. The quantum wells were grown by molecular beam epitaxy and found to be of a high structural perfection as evidenced in the high resolution x-ray diffraction measurements. The photoluminescence was more intense from the quantum wells grown on the metamorphic buffer layer and persisted up to room temperature. The mid-infrared emission spectra were analysed, and the observed transitions were found to be in good agreement with the calculated emission energies.

  6. Semiclassical three-valley Monte Carlo simulation analysis of steady-state and transient electron transport within bulk InAsxP1-x, InAs and InP

    Directory of Open Access Journals (Sweden)

    Hadi Arabshahi

    2010-04-01

    Full Text Available We have studied how electrons, initially in thermal equilibrium, drift under the action of an applied electric field within bulk zincblende InAsxP1-x, InAs and InP. Calculations are made using a non-parabolic effective-mass energy band model. Monte Carlo simulation includes all of the major scattering mechanisms. The band parameters used in the simulation are extracted from optimised pseudo-potential band calculations to ensure excellent agreement with experimental information and ab-initio band models. The effects of alloy scattering on the electron transport physics are examined. For all materials, it is found that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material parameters. Transient velocity overshoot has also been simulated, with the sudden application of fields up to 1600 kVm-1, appropriate to the gate-drain fields expected within an operational field-effect transistor. The electron drift velocity relaxes to the saturation value of about 1.5105 ms-1 within 4 pico-seconds for all crystal structures. The steady-state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

  7. Modification of electrical properties of Au/n-type InP Schottky diode with a high-k Ba0.6Sr0.4TiO3 interlayer

    Science.gov (United States)

    Thapaswini, P. Prabhu; Padma, R.; Balaram, N.; Bindu, B.; Rajagopal Reddy, V.

    2016-05-01

    Au/Ba0.6Sr0.4TiO3 (BST)/n-InP metal/insulator/semiconductor (MIS) Schottky diodes have been analyzed by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The surface morphology of the BST films on InP is fairly smooth. The Au/BST/n-InP MIS Schottky diode shows better rectification ratio and low leakage current compared to the conventional Au/n-InP metal-semiconductor (MS) Schottky diode. Higher barrier height is achieved for the MIS Schottky diode compared to the MS Schottky diode. The Norde and Cheung's methods are employed to determine the barrier height, ideality factor and series resistance. The interface state density (NSS) is determined from the forward bias I-V data for both the MS and MIS Schottky diodes. Results reveal that the NSS of the MIS Schottky diode is lower than that of the MS Schottky diode. The Poole-Frenkel emission is found dominating the reverse current in both Au/n-InP MS and Au/BST/n-InP MIS Schottky diodes, indicating the presence of structural defects and trap levels in the dielectric film.

  8. Analisis dan Optimasi Desain Sistem Reaktor Gas Temperatur Tinggi RGTT200K dan RGTT200KT

    Directory of Open Access Journals (Sweden)

    Mohammad Dhandhang Purwadi

    2013-03-01

    dengan penyelesaian persamaan aljabar linier dari model RGTT200K dan RGTT200KT. Dari analisis dan optimasi ini dihasilkan desain konseptual sistem RGTT200K dan RGTT200KT dengan spesifikasi thermal-flow teras sama, dan peningkatan EUF dari 63% menjadi 80,14% (untuk RGTT200K dan dari 63,6% menjadi 78,02% (untuk RGTT200KT.

  9. Theory of nuclear reactors. Vol. 1. Theorie der Kernreaktoren. Bd. 1. Der stationaere Reaktor

    Energy Technology Data Exchange (ETDEWEB)

    Emendoerfer, D.; Hoecker, K.H.

    1982-01-01

    An introduction is given to the elements of reactor physics and reactor calculation which refers to practice from the present point of view. It is demonstrated to the reader how the reactor characteristics relevant to construction can be calculated from atomic factors by means of neutron transport and diffusion theory; these reactor characteristics are: multiplication factor, power density distribution, burn-up, plutonium build-up, xenon vibrations, short-time behaviour. The interaction between thermo- and fluid-dynamic processes is important for this calculation. On grounds of didactics the crucial point of this book is the establishment and calculation of simple models which give a clear description of all important characteristics of the events. Attempts for more exact simulation by computer are dealt with including typical solutions.

  10. UNJUK KERJA REAKTOR PLASMA DIELECTRIC BARRIER DISCHARGE UNTUK PRODUKSI BIODIESEL DARI MINYAK KELAPA SAWIT

    Directory of Open Access Journals (Sweden)

    Ardian Dwi Yudhistira

    2013-10-01

    Full Text Available Biodiesel is one of alternative renewable energy source to substitute diesel fuel. Various biodiesel productionprocesses through transesterification reaction with a variety of catalysts have been developed by previousresearcher. This process still has the disadvantage of a long reaction time, and high energy need. DielectricBarrier Discharge (DBD plasma electro-catalysis may become a solution to overcome the drawbacks in theconventional transesterification process. This process only needs a short time reaction and low energy process.The purpose of this study was to assess the performance of DBD plasma rector in making biodiesel such as: theeffect of high voltage electric value, electrodes gap, mole ratio of methanol / oil, and reaction time. TheResearch method was using GC-MS (Gas Cromatography-Mass Spectrofotometry and FTIR (FourierTransform Infrared Spectrofotometry and then it will be analysed the change of chemical bond betweenreactant and product. So, the reaction mechanism can be predicted. Biodiesel is produced using methanol andpalm oil as reactants and DBD plasma used as reactor in batch system. Then, reactants contacted by highvoltage electric. From the results of this research can be concluded that the reaction mechanism occurs in theprocess is the reaction mechanism of cracking, the higher of electric voltage and the longer of reaction time leadto increasing of product yield. The more of mole ratio of methanol / oil and widening the gap between theelectrodes lead to decreased product yield. From this research, product yield maksimum is 89,8% in the variableof rasio mol metanol/palm oil 3:1, voltage 10 kV, electrode gap 1,5 cm, and reaction time 30 seconds.

  11. Trajetória de egressos da pós- graduação do Instituto Nacional de Pesquisas Espaciais: uma ferramenta para avaliação Tracking alumni of the National Institute of Space Research (INPE: a tool for program evaluation

    Directory of Open Access Journals (Sweden)

    Maria Lígia Moreira

    2012-03-01

    Full Text Available Este trabalho analisa a trajetória acadêmica e o destino profissional dos egressos dos cursos de mestrado e doutorado do Instituto Nacional de Pesquisas Espaciais (INPE. Para isso, foram realizados levantamento e análise dos dados de 1098 egressos, titulados no período 1968 a 2009, nos cursos de Astronomia, Geofísica Espacial, Meteorologia, Engenharia e Tecnologia Espaciais, Computação Aplicada e Sensoriamento Remoto. Os resultados mostram a relevância das atividades de ensino do Instituto para o desenvolvimento da ciência espacial no país, assim como a importância dos mecanismos de avaliação de desempenho e impacto como subsídios ao planejamento e às ações de formação de competências.This work analyses the academic trajectory and professional activities of space science specialists who received their Masters and PhD degrees in graduate programs offered by the Brazilian Institute for Space Research (INPE. The analysis is based on data about 1,098 graduates who got their degrees in Astronomy, Space Geophysics, Meteorology, Space Technology and Remote Sensing between 1968 and 2009. The results show the relevance of the graduate education they received to the development of activities in space science in the country. It also documents the importance of developing evaluation tools so that graduate programs in general and INPE in particular can better plan its capacity building activities.

  12. Non-Debye heat capacity formula refined and applied to GaP, GaAs, GaSb, InP, InAs, and InSb

    Directory of Open Access Journals (Sweden)

    R. Pässler

    2013-08-01

    Full Text Available Characteristic non-Debye behaviors of low-temperature heat capacities of GaP, GaAs, GaSb, InP, InAs, and InSb, which are manifested above all in form of non-monotonic behaviors (local maxima of the respective Cp(T/T3 curves in the cryogenic region, are described by means of a refined version of a recently proposed low-to-high-temperature interpolation formula of non-Debye type. Least-mean-square fittings of representative Cp(T data sets available for these materials from several sources show excellent agreements, from the liquid-helium region up to room temperature. The results of detailed calculations of the respective material-specific Debye temperature curves, ΘD(T, are represented in graphical form. The strong, non-monotonic variations of ΘD(T values confirm that it is impossible to provide reasonable numerical simulations of measured Cp(T dependences in terms of fixed Debye temperatures. We show that it is possible to describe in good approximation the complete Debye temperature curves, from the cryogenic region up to their definitive disappearance (dropping to 0 in the high temperature region, by a couple of unprecedented algebraic formulas. The task of constructing physically adequate prolongations of the low-temperature Cp(T curves up to melting points was strongly impeded by partly rather large differences (up to an order of 10 J/(K·mol between the high-temperature data sets presented in different research papers and/or data reviews. Physically plausible criteria are invoked, which enabled an a priori rejection of a series of obviously unrealistic high-temperature data sets. Residual uncertainties for GaAs and InAs could be overcome by re-evaluations of former enthalpy data on the basis of a novel set of properly specified four-parameter polynomial expressions applying to large regions, from moderately low temperatures up to melting points. Detailed analytical and numerical descriptions are given for the anharmonicity

  13. 8-band and 14-band kp modeling of electronic band structure and material gain in Ga(In)AsBi quantum wells grown on GaAs and InP substrates

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, M.; Wartak, M. S. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Kudrawiec, R. [Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

    2015-08-07

    The electronic band structure and material gain have been calculated for GaAsBi/GaAs quantum wells (QWs) with various bismuth concentrations (Bi ≤ 15%) within the 8-band and 14-band kp models. The 14-band kp model was obtained by extending the standard 8-band kp Hamiltonian by the valence band anticrossing (VBAC) Hamiltonian, which is widely used to describe Bi-related changes in the electronic band structure of dilute bismides. It has been shown that in the range of low carrier concentrations n < 5 × 10{sup 18 }cm{sup −3}, material gain spectra calculated within 8- and 14-band kp Hamiltonians are similar. It means that the 8-band kp model can be used to calculate material gain in dilute bismides QWs. Therefore, it can be applied to analyze QWs containing new dilute bismides for which the VBAC parameters are unknown. Thus, the energy gap and electron effective mass for Bi-containing materials are used instead of VBAC parameters. The electronic band structure and material gain have been calculated for 8 nm wide GaInAsBi QWs on GaAs and InP substrates with various compositions. In these QWs, Bi concentration was varied from 0% to 5% and indium concentration was tuned in order to keep the same compressive strain (ε = 2%) in QW region. For GaInAsBi/GaAs QW with 5% Bi, gain peak was determined to be at about 1.5 μm. It means that it can be possible to achieve emission at telecommunication windows (i.e., 1.3 μm and 1.55 μm) for GaAs-based lasers containing GaInAsBi/GaAs QWs. For GaInAsBi/Ga{sub 0.47}In{sub 0.53}As/InP QWs with 5% Bi, gain peak is predicted to be at about 4.0 μm, i.e., at the wavelengths that are not available in current InP-based lasers.

  14. The optical constants of n- and p-doped In{sub 0.66}Ga{sub 0.34}As on InP (001) including the Burstein-Moss shift: Experiment and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Holden, T.; Pollak, F.H. [City Univ. of New York, Brooklyn, NY (United States); Freeouf, J.L. [Interface Studies, Inc., Katonah, NY (United States); Charache, G.W.; Raynolds, J.E. [Lockheed-Martin Corp., Schenectady, NY (United States)

    1998-10-01

    The complex optical constants (real and imaginary components of the dielectric function and index of refraction) and absorption coefficient in the range 0.3--5.5 eV have been evaluated at 300K using spectral ellipsometry for a series of n-(5.7 {times} 10{sup 17} cm{sup {minus}3} < n < 5.5 {times} 10{sup 19} cm{sup {minus}3}) and p-(6.5 {times} 10{sup 17} cm{sup {minus}3} < p < 5.0 {times} 10{sup 10} cm{sup {minus}3}) doped relaxed In{sub 0.66}Ga{sub 0.34}As grown by metalorganic chemical vapor deposition on InP (001). The authors have observed the fundamental absorption edge, spin-orbit split E{sub 1}-R{sub 1}, (E{sub 1}+{Delta}{sub 1})-R{sub 1} doublet and E{sub 2} feature. The data have been fit using a comprehensive model based on the electronic energy-band structure near critical points plus relevant excitonic and band-to-band Coulomb enhancement (BBCE) effects. The intrinsic band gap of 0.612 {+-} 0.01 eV corresponds to an In composition of 66 {+-} 1%. The Burstein-Moss (BM) shift was accounted for using a Fermi level filling factor in addition to the excitonic and BBCE terms. While for the p-type samples the BM shift exhibited only parabolic effects, the n-type samples had pronounced non-parabolicity at the highest doping level, in agreement with a bandstructure calculation. By accounting for the BBCE term the authors have obtained the binding energy, R{sub 1}, of the 2D exciton associated with E{sub 1}-R{sub 1}, (E{sub 1} + {Delta}{sub 1})-R{sub 1} features. Except for Holden et al. this quantity has not been obtained from any previous ellipsometric or other optical studies.

  15. Zinc Telluride Growth on InP

    Science.gov (United States)

    1989-01-14

    evaporation at high bakel .,ut temperatures. In the present case, subsequent to the wet chemical preparation stage 2 a , v o bakeout under hydrogen at...ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S) WOARD - R - a ~s llI 6.NAME OF PERFORMING ORGANIZATION 16b. OFFICE SYMBO8L 7a...peaks. It proved impossible with our atmospheric pressure MOCVD reactor and, us ing, a conventional source of Te to prepared epitaxial layers of the

  16. Properties of lattice matched quaternary InAlGaAs on InP substrate grown by gas source MBE%InP衬底上晶格匹配四元系InAlGaAs的气态源分子束外延生长

    Institute of Scientific and Technical Information of China (English)

    王凯; 顾溢; 方祥; 周立; 李成; 李好斯白音; 张永刚

    2012-01-01

    Properties of quaternary InAlGaAs alloys prepared by gas source MBE growth have been investigated with high resolution X-ray diffraction rocking curves,photoluminescence and Hall measurements.X-ray rocking curves show that all the samples are well matched to InP substrate according to calibration data.The photoluminescence and Hall measurement show that the PL intensity,electron concentration and mobility decrease distinctly as Al composition increases.The group Ⅲ compositions are determined from both photoluminescence and x-ray diffraction measurements,and agreed well with the designed values.The relationship between the designed Al compositions and measured values provides us a practical way for the precise composition control.%采用高分辨率X射线衍射摇摆曲线、光致发光以及霍尔测试对采用气态源分子束外延方法生长的四元系InAlGaAs材料性质进行了表征.摇摆曲线结果表明,根据计算数据所生长的InAlGaAs样品与InP衬底基本匹配.光致发光和霍尔测试结果显示随着Al组分的增加,样品的光致发光强度、电子浓度和迁移率均有所下降.样品的三族元素组分由光致发光及X射线衍射实验获得,测试结果与设计值吻合,Al组分的实验设计值与测试结果的关系提供了一种实用的精确控制组分的方法.

  17. Scavi e ricerche ad Althiburos (INP e ISMA-CNR

    Directory of Open Access Journals (Sweden)

    Massimo Botto

    2017-03-01

    Full Text Available L’Institut National du Patrimoine e l’Istituto di Studi sul Mediterraneo Antico del Consiglio Nazionale delle Ricerche conducono da vari anni ricerche archeologiche nel sito di el Médéïna, l’antica Althiburos. Qui si presentano gli aspetti principali della cooperazione tunisino-italiana e alcuni dei risultati finora raggiunti. The Tunisian National Heritage Institute and the Institute for the Studies on Ancient Mediterranean, of the Italian National Research Council, lead by several years archaeological research in el Médéïna (ancient Althiburos. Here we present the main aspects of the Tunisian-Italian cooperation and an assessment of the results achieved so far.

  18. Experimental examination of gaas dissolution in in-p melt

    Science.gov (United States)

    Bolkhovityanov, Yu. B.; Bolkhovityanova, R. I.; Chikichev, S. I.

    1983-05-01

    The “solubility” of GaAs crystals in quaternary In-Ga-As-P liquids (X{Ga/I} = X{As/I}) has been studied experi-mentally at 770°C using seed-dissolution technique. The location of the true liquidus isotherm has been established independently by means of the direct vi-sual observation technique. Comparison between the two data sets indicates that the first method can be successfully used only for those In-Ga-As-P melt compositions which have the corresponding solid InxGa1-xAsyP1-y alloys nearly lattice-matched to the GaAs substrate. In other cases the results obtained by this method are totally misleading although in-teresting as they are. The phenomenon of “catastro-phic” substrate erosion is investigated. The results of the present study are interpreted within the conceptual framework developed previously.

  19. Sinterless Fabrication Of Contact Pads On InP Devices

    Science.gov (United States)

    Weizer, Victor G.; Fatemi, Navid S.; Korenyi-Both, Andras L.

    1995-01-01

    Research has shown that with proper choice of material, low-resistance contact pads deposited on solar cells and other devices by improved technique that does not involve sintering. Research directed at understanding mechanisms involved in contact-sintering process has resulted in identification of special group of materials that includes phosphides of gold, silver, and nickel; specifically, Au(2)P(3), AgP(2), and Ni(3)P. Incorporation of phosphide interlayer substantially reduces resistivity between gold current-carrying layer and indium phosphide substrate. Further research indicated only very thin interlayer of any of these compounds needed to obtain low contact resistance, without subjecting contact to destructive sintering process.

  20. Imaging pancreatic cancer using bioconjugated InP quantum dots.

    Science.gov (United States)

    Yong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J; Maitra, Anirban; Prasad, Paras N

    2009-03-24

    In this paper, we report the successful use of non-cadmium-based quantum dots (QDs) as highly efficient and nontoxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulfide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in nonaqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anticlaudin 4 and antiprostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor-mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in nonpancreatic cancer based cell lines which are negative for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium-based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer.

  1. Imaging Pancreatic Cancer Using Bioconjugated InP Quantum Dots

    OpenAIRE

    2009-01-01

    In this paper, we report the successful use of non-cadmium based quantum dots (QDs) as highly efficient and non-toxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulphide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in non-aqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjug...

  2. Contact metallurgy optimization for ohmic contacts to InP

    DEFF Research Database (Denmark)

    Clausen, Thomas; Pedersen, Arne Skyggebjerg; Leistiko, Otto

    1991-01-01

    AuGeNi and AuZnNi metallizations to n- and p-InP were studied as a function of the annealing temperature in a Rapid Thermal Annealing (RTA) system. For n-InP (S:8×1018cm-3) a broad minimum existed from 385°C to 500°C, in which the specific contact resistance, rc, was about 10-7 ¿cm2. The lowe...

  3. InP Transferred Electron Cathodes: Basic to Manufacturing Methods

    Science.gov (United States)

    2007-08-29

    4 R. Sankaran et al, J. Vac. Sci. Technol. 13, 932 (1976) 5 J. S. Escher , IEEE Trans. Elec. Dev. 27, 1244 (1980) 6 R. L. Bell et al, Appl. Phys...Lett. 19, 513 (1971) 7 J. S. Escher et al, J. Appl. Phys. 49, 2591 (1978) 15 8 R. L. Bell, L. W. James, R. L. Moon, Appl. Phys. Lett. 25, 645 (1974...9 J. S. Escher , R. Sankaran, Appl. Phys. Lett. 29, 87 (1976) 10 J. S. Escher et al, CRC Crit. Rev. Solid State Sci. 5, 577 (1975) 11 R. L. Bell, W

  4. Compact, Single-Stage MMIC InP HEMT Amplifier

    Science.gov (United States)

    Pukala, David; Samoska, Lorene; Fung, King Man; Gaier, Todd; Deal, W. R.; Mei, Gerry; Radisic, Vesna; Lai, Richard

    2008-01-01

    A monolithic micro - wave integrated-circuit (MMIC) singlestage amplifier containing an InP-based high-electron-mobility transistor (HEMT) plus coplanar-waveguide (CPW) transmission lines for impedance matching and input and output coupling, all in a highly miniaturized layout as needed for high performance at operating frequencies of hundreds of gigahertz is described.

  5. Photoluminescence Imaging Characterization of Thin-Film InP

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Steve; Allende Motz, Alyssa; Moore, James; Zheng, Maxwell; Javey, Ali; Bermel, Peter

    2015-06-14

    Indium phosphide grown using a novel vapor-liquid-solid method is a promising low-cost material for III-V single-junction photovoltaics. In this work, we characterize the properties of these materials using photoluminescence (PL) imaging, time-resolved photoluminescence (TRPL), and microwave-reflection photoconductive decay (u-PCD). PL image data clearly shows the emergence of a self-similar dendritic growth network from nucleation sites, while zoomed-in images show grain structure and grain boundaries. Single photon TRPL data shows initial surface-dominated recombination, while two-photon excitation TRPL shows a lifetime of 10 ns. Bulk carrier lifetime may be as long as 35 ns as measured by u-PCD, which can be less sensitive to surface recombination.

  6. InP (Indium Phosphide): Into the future

    Science.gov (United States)

    Brandhorst, Henry W., Jr.

    1989-01-01

    Major industry is beginning to be devoted to indium phosphide and its potential applications. Key to these applications are high speed and radiation tolerance; however the high cost of indium phosphide may be an inhibitor to progress. The broad applicability of indium phosphide to many devices will be discussed with an emphasis on photovoltaics. Major attention is devoted to radiation tolerance and means of reducing cost of devices. Some of the approaches applicable to solar cells may also be relevant to other devices. The intent is to display the impact of visionary leadership in the field and enable the directions and broad applicability of indium phosphide.

  7. Svar til: Hvorfor bryder robotter sammen i Tjernobyl-reaktor? (Ingeniøren, lørdag d. 17 nov. 2007)

    DEFF Research Database (Denmark)

    Morgen, Per

    2007-01-01

    Som svar på spørgsmålet om, hvorfor man ikke kunne tage billeder med robotter og digitalkameraer i en af Tjernobyls "sarkofager", har jeg fundet en artikel om emnet fra 2006: Investigating the influence of ionizing radiation on standard CCD cameras and a possible impact on photogrammetric...... Symposium 'Image Engineering and Vision Metrology'. Det er kendt af folk, der beskæftiger sig med mikroelektronik, at computerchips og hukommelseskredse kan blive sat ud af spillet, når de bliver udsat for radioaktivitet, og derfor vil også en computerstyret robot være sårbar overfor dette. Radioaktiv...

  8. Svar til: Hvorfor bryder robotter sammen i Tjernobyl-reaktor? (Ingeniøren, lørdag d. 17 nov. 2007)

    DEFF Research Database (Denmark)

    Morgen, Per

    2007-01-01

    stråling i form af partikler eller gamma- og røntgenstråling ioniserer på deres vej igennem siliciummet de atomer, som de møder på deres vej. Derved dannes der inde i chippen løse elektroner og huller, som kan frembringe falske elektroniske signaler i den. Hvis man er uheldig, ændrer disse signaler...

  9. Determination of the reactivity coefficient of a sodium cooled reactor with metallic fuel; Bestimmung der Reaktivitaetskoeffizienten eines schnellen natriumgekuehlten Reaktors mit metallischem Brennstoff

    Energy Technology Data Exchange (ETDEWEB)

    Guilliard, N. [Stuttgart Univ. (Germany). Inst. fuer Kernenergetik und Energiesysteme (IKE)

    2013-07-01

    Fast sodium cooled breeding reactors are of interest in the frame of the Generation IV reactor design. Die to the experience in France and Japan the concept seems to be realizable in the near future. Due to the new design concepts the accident scenarios and the safety analyses based on modern simulation codes have to be adjusted in the frame of the European JASMIN project. The project is aimed to develop a European accident code for fast breeder reactors based on the modular LWR code ASTEC. Extensions with respect to sodium as coolant, improved physical models and the different design are necessary. Besides this a point kinetic model shall be implemented. The coupling of point kinetic neutronics to a thermal hydraulic code requires the determination of the reactivity coefficients of the respective system. Using the core design of a benchmark specification OECD/NEA SFR task force the reactivity coefficients are determined as an example.

  10. The vegetation as sink and biochemical reactor for airborne pollutants. Final report; Die Vegetation als Senke und biochemischer Reaktor fuer luftgetragene Schadstoffe. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Weissflog, L.; Wenzel, K.D. [UFZ - Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany). Sektion Chemische Oekotoxikologie

    1997-06-30

    The present project involved extensive studies on the air pollution situation and interactions between organic as well as inorganic air pollutant levels and the vegetation in three east German states. Seven monitoring sites with different emission profiles were selected in Saxony-Anhalt, one typically polluted site in Saxony, and two less polluted sites in Mecklenburg-Western Pomerania. The following emitter types were found to exhibit consistent pollutant patterns: landfills receiving chloroorganic special wastes; hard-coal-fuelled firing installations; commercial charcoal plants; industry; industry - car traffic - domestic fuel combustion; car traffic. [Deutsch] Im Verlauf der Projektarbeiten wurden an sieben durch unterschiedliche Emittententypen belasteten Standorten in Sachsen-Anhalt, einem typisch belasteten Standort in Sachsen und an zwei weniger belasteten Standorten in Mecklenburg/Vorpommern umfangreiche Untersuchungen zur Immissionssituation und der Wechselwirkung der luftgetragenen anorganischen und organischen Schadstofffracht mit der Vegetation durchgefuehrt. Dabei konnten fuer folgende Emittenten charakteristische Schadstoffmuster ermittelt werden: - Deponien mit chlororganischem Sondermuell - Feuerungsanlagen fuer Steinkohle - Gewerbliche Anlagen zur Herstellung von Holzkohle - Industrie - Industrie/Kfz-Verkehr/Hausbrand - Kfz-Verkehr. (orig.)

  11. The vegetation as sink and biochemical reactor for airborne pollutants. Final report; Die Vegetation als Senke und biochemischer Reaktor fuer luftgetragene Schadstoffe. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Weissflog, L.; Wenzel, K.D. [UFZ - Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany). Sektion Chemische Oekotoxikologie

    1997-06-30

    The present project involved extensive studies on the air pollution situation and interactions between organic as well as inorganic air pollutant levels and the vegetation in three east German states. Seven monitoring sites with different emission profiles were selected in Saxony-Anhalt, one typically polluted site in Saxony, and two less polluted sites in Mecklenburg-Western Pomerania. The following emitter types were found to exhibit consistent pollutant patterns: landfills receiving chloroorganic special wastes; hard-coal-fuelled firing installations; commercial charcoal plants; industry; industry - car traffic - domestic fuel combustion; car traffic. [Deutsch] Im Verlauf der Projektarbeiten wurden an sieben durch unterschiedliche Emittententypen belasteten Standorten in Sachsen-Anhalt, einem typisch belasteten Standort in Sachsen und an zwei weniger belasteten Standorten in Mecklenburg/Vorpommern umfangreiche Untersuchungen zur Immissionssituation und der Wechselwirkung der luftgetragenen anorganischen und organischen Schadstofffracht mit der Vegetation durchgefuehrt. Dabei konnten fuer folgende Emittenten charakteristische Schadstoffmuster ermittelt werden: - Deponien mit chlororganischem Sondermuell - Feuerungsanlagen fuer Steinkohle - Gewerbliche Anlagen zur Herstellung von Holzkohle - Industrie - Industrie/Kfz-Verkehr/Hausbrand - Kfz-Verkehr. (orig.)

  12. Development for InP MISFET for OEIC%用于OEIC的InPMISFET的研制

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    用MOCVD方法生长了n+-InP/n-InP/SI-InP材料,以HfO2为介质膜,用电子束蒸发和选择化学腐蚀研制成栅宽0.002mm、栅长为0.2mm的具有蘑菇状栅极结构的InPMISFET.直流特性测量表明,跨导gm=80-115ms/mm,开启电压VT-3.62V,沟道的有效电子迁移率ueff=674cm2/V·S,界面态密度NSS=9.56×1011cm-2.设计计算的特征频率fT=97.1GHz,最高特征频率fmax=64.7GHz,尚未发现器件性能的漂移现象.本器件可作为InP基的单片光电子集成器件(OEIC)的放大部分.

  13. A Verilog-A large signal model for InP DHBT including thermal effects

    Science.gov (United States)

    Yuxia, Shi; Zhi, Jin; Zhijian, Pan; Yongbo, Su; Yuxiong, Cao; Yan, Wang

    2013-06-01

    A large signal model for InP/InGaAs double heterojunction bipolar transistors including thermal effects has been reported, which demonstrated good agreements of simulations with measurements. On the basis of the previous model in which the double heterojunction effect, current blocking effect and high current effect in current expression are considered, the effect of bandgap narrowing with temperature has been considered in transport current while a formula for model parameters as a function of temperature has been developed. This model is implemented by Verilog-A and embedded in ADS. The proposed model is verified with DC and large signal measurements.

  14. A quantum entropy source on an InP photonic integrated circuit for random number generation

    CERN Document Server

    Abellan, Carlos; Domenech, David; Muñoz, Pascual; Capmany, Jose; Longhi, Stefano; Mitchell, Morgan W; Pruneri, Valerio

    2016-01-01

    Random number generators are essential to ensure performance in information technologies, including cryptography, stochastic simulations and massive data processing. The quality of random numbers ultimately determines the security and privacy that can be achieved, while the speed at which they can be generated poses limits to the utilisation of the available resources. In this work we propose and demonstrate a quantum entropy source for random number generation on an indium phosphide photonic integrated circuit made possible by a new design using two-laser interference and heterodyne detection. The resulting device offers high-speed operation with unprecedented security guarantees and reduced form factor. It is also compatible with complementary metal-oxide semiconductor technology, opening the path to its integration in computation and communication electronic cards, which is particularly relevant for the intensive migration of information processing and storage tasks from local premises to cloud data centre...

  15. Study of Ultra Short HFET Devices with InP Substrates

    Science.gov (United States)

    1992-01-30

    MBE growth , and sharply (-100:1) reduction of the gate breakdown current by using a barrier-enhancement acceptor doping plane under the gate. Near pinch-off, the drain-source voltage at breakdown was doubled. Additionally, the optimization of the fabrication technology of the mushroom (or T) shaped gates was completed for these devices, and integrated circuits for millimeter amplifiers and oscillators were designed and

  16. Modelling and characterization of a travelling-wave electro-optic modulator on InP

    Directory of Open Access Journals (Sweden)

    W. Pascher

    2003-01-01

    Full Text Available A fast travelling-wave Mach-Zehnder modulator is modelled and designed using a rigorous vectorial analysis. In order to investigate propagation characteristics, velocity and microwave loss, the semiconductor layer stack and the lossy electrodes are modelled using the method of lines. The microwave field distribution is determined, design curves are derived and the cross-sectional dimensions of the modulator are optimized. The loss of the fabricated device agrees very well with small signal measurements up to 40 GHz and HFSS simulations.

  17. Enhanced EOS photovoltaic power system capability with InP solar cells

    Science.gov (United States)

    Bailey, Sheila G.; Weinberg, Irving; Flood, Dennis J.

    1991-01-01

    The Earth Observing System (EOS), which is part of the International Mission to Planet Earth, is NASA's main contribution to the Global Change Research Program which opens a new era in international cooperation to study the Earth's environment. Five large platforms are to be launched into polar orbit, two by NASA, two by ESA, and one by the Japanese. In such an orbit the radiation resistance of indium phosphide solar cells combined with the potential of utilizing five micron cell structures yields an increase of 10 percent in the payload capability. If further combined with the advanced photovoltaic solar array the payload savings approaches 12 percent.

  18. InP nanowires from surfactant-free thermolysis of single molecule precursors.

    Science.gov (United States)

    Banerjee, Chiranjib; Hughes, David L; Bochmann, Manfred; Nann, Thomas

    2012-06-28

    Indium phosphide nanofibres were grown from a single-molecule precursor, [(PhCH(2))(2)InP(SiMe(3))(2)](2), using hot injection techniques by a solution-liquid-solid (SLS) process, under "surfactant-free" conditions and without the use of protic additives. The fibres are 85-95 nm in diameter and grow from In metal droplets of 100 nm diameter. The length of the nanofibres is a function of the precursor injection temperature (rather than the growth temperature) and can be varied from 6000 nm at 210 °C to 1000 nm at 310 °C. The indium metal tip can be readily removed under mild, non-etching conditions by treatment with thiophenol-P(SiMe(3))(3) mixtures.

  19. Room Temperature InP DFB Laser Array Directly Grown on (001) Silicon

    CERN Document Server

    Wang, Zhechao; Pantouvaki, Marianna; Guo, Weiming; Absil, Philippe; Van Campenhout, Joris; Merckling, Clement; Van Thourhout, Dries

    2015-01-01

    Fully exploiting the silicon photonics platform requires a fundamentally new approach to realize high-performance laser sources that can be integrated directly using wafer-scale fabrication methods. Direct band gap III-V semiconductors allow efficient light generation but the large mismatch in lattice constant, thermal expansion and crystal polarity makes their epitaxial growth directly on silicon extremely complex. Here, using a selective area growth technique in confined regions, we surpass this fundamental limit and demonstrate an optically pumped InP-based distributed feedback (DFB) laser array grown on (001)-Silicon operating at room temperature and suitable for wavelength-division-multiplexing applications. The novel epitaxial technology suppresses threading dislocations and anti-phase boundaries to a less than 20nm thick layer not affecting the device performance. Using an in-plane laser cavity defined by standard top-down lithographic patterning together with a high yield and high uniformity provides ...

  20. Multiport InP monolithically integrated all-optical wavelength router.

    Science.gov (United States)

    Zheng, Xiu; Raz, Oded; Calabretta, Nicola; Zhao, Dan; Lu, Rongguo; Liu, Yong

    2016-08-15

    An indium phosphide-based monolithically integrated wavelength router is demonstrated in this Letter. The wavelength router has four input ports and four output ports, which integrate four wavelength converters and a 4×4 arrayed-waveguide grating router. Each wavelength converter is achieved based on cross-gain modulation and cross-phase modulation effects in a semiconductor optical amplifier. Error-free wavelength switching for a non-return-to-zero 231-1 ps eudorandom binary sequence at 40 Gb/s data rate is performed. Both 1×4 and 3×1 all-optical routing functions of this chip are demonstrated for the first time with power penalties as low as 3.2 dB.

  1. A voltage-controlled ring oscillator using InP full enhancement-mode HEMT logic

    Science.gov (United States)

    Rui, Du; Yang, Dai; Yanling, Chen; Fuhua, Yang

    2009-03-01

    A voltage-controlled ring oscillator (VCO) based on a full enhancement-mode InAlAs/InGaAs/InP high electron mobility transistor (HEMT) logic is proposed. An enhancement-mode HEMT (E-HEMT) is fabricated, whose threshold is demonstrated to be 10 mV. The model of the E-HEMT is established and used in the SPICE simulation of the VCO. The result proves that the full E-HEMT logic technology can be applied to the VCO. And compared with the HEMT DCFL technology, the complexity of our fabrication process is reduced and the reliability is improved.

  2. InP chip scale integration platform for high performance tunable lasers

    Science.gov (United States)

    Simes, Robert J.; Fish, Gregory A.; Abraham, Patrick; Akulova, Yuliya A.; Coldren, Christopher W.; Focht, Marlin; Hall, Eric M.; Larson, Mike C.; Marchand, Hugues; Kozodoy, Peter; Dahl, Anders; Koh, Ping C.; Strand, T.

    2003-12-01

    Tunable semiconductor lasers have been listed in numerous critical technology lists for future optical communication systems. Lasers with full band tuning ranges (C or L) allow reduction of the inventory cost and simplify deployment and operation of existing systems in addition to enabling wavelength agile networking concepts in future systems. Furthermore, monolithic integration of full band tunable lasers with modulators to form complete transmitters offers the most potential for reducing system size, weight, power consumption, and cost. This paper summarizes design, fabrication technology, and performance characteristics of widely tunable CW sources and transmitters based on chip scale integration of a Sampled Grating Distributed Bragg Reflector (SG DBR) laser with a Semiconductor Optical Amplifier (SOA) and Electroabsorption (EA) or Mach Zehnder (MZ) modulator. Widely tunable CW sources based on SG-DBR lasers exhibit high fiber coupled output power (20 mW CW) and side mode suppression ratio (>40 dB), low relative intensity noise (below -140 dB/Hz) and line width ( 10 dB, and error-free transmission over 350 km of standard fiber at 2.5 Gb/s across a 40 nm tuning range. Monolithic integration of widely tunable lasers with MZ modulators allow for further extension of bit rate (10 Gb/s and beyond) and transmission distances through precise control of the transient chirp of the transmitter. Systematic investigations of accelerated aging confirm that reliability of these widely-tunable transmitters is sufficient for system deployment.

  3. A voltage-controlled ring oscillator using InP full enhancement-mode HEMT logic

    Institute of Scientific and Technical Information of China (English)

    Du Rui; Dai Yang; Chen Yanling; Yang Fuhua

    2009-01-01

    A voltage-controlled ring oscillator (VCO) based on a full enhancement-mode InAIAs/InGaAs/InP high electron mobility transistor (HEMT) logic is proposed. An enhancement-mode HEMT (E-HEMT) is fabricated, whose threshold is demonstrated to be 10 mV. The model of the E-HEMT is established and used in the SPICE simulation of the VCO. The result proves that the full E-HEMT logic technology can be applied to the VCO. And compared with the HEMT DCFL technology, the complexity of our fabrication process is reduced and the reliability is improved.

  4. Electrical Compensation in InP Produced by Background Impurities and Structural Defects

    Science.gov (United States)

    1980-10-01

    parts HC1 and 1 part HNO 3) for a minimum of 20 minutes, to dissolve heavy metals, and then rinsed thorougly with DI water. 5. Step 3 a-e is repeated and...34Pellon" pad mounted on a ii,, . •.-,• • - -- - . . . . •- ’T -Pr-WW_ -7- tilted rotating table. The substrates are cemented with beeswax to a

  5. Physico-chemical mechanism for the vapors sensitivity of photoluminescent InP quantum dots

    Science.gov (United States)

    Prosposito, P.; De Angelis, R.; De Matteis, F.; Hatami, F.; Masselink, W. T.; Zhang, H.; Casalboni, M.

    2016-03-01

    InP/InGaP surface quantum dots are interesting materials for optical chemical sensors since they present an intense emission at room temperature, whose intensity changes rapidly and reversibly depending on the composition of the environmental atmosphere. We present here their emission properties by time resolved photoluminescence spectroscopy investigation and we discuss the physico-chemical mechanism behind their sensitivity to the surrounding atmosphere. Photoluminescence transients in inert atmosphere (N2) and in solvent vapours of methanol, clorophorm, acetone and water were measured. The presence of vapors of clorophorm, acetone and water showed a very weak effect on the transient times, while an increase of up to 15% of the decay time was observed for methanol vapour exposure. On the basis of the vapor molecule nature (polarity, proticity, steric hindrance, etc.) and of the interaction of the vapor molecules with the quantum dots surface a sensing mechanism involving quantum dots non-radiative surface states is proposed.

  6. The Effect of Fatty Amine Chain Length on Synthesis Process of Inp/Zns Quantum Dots

    OpenAIRE

    2016-01-01

    Obtaining narrow size distribution through conventional methods used for quantum dots of group II-VI semiconductors is impractical in the case of III-V semiconductors speciallyInP/ZnS quantum dots because of molecular precursors depletion and growth stage continuation through Ostwald ripening process. Using fatty amines as activator along with precursors can lead to more monodispersed quantum dots. In this work, the effect of fatty amine chain length on InP/ZnS quantum dots synthesis was inve...

  7. Radoptic effect in InP and GaN for ultrafast scintillator applications

    Science.gov (United States)

    Brown, Kristina; Steele, Paul; Curtis, Alden

    2014-09-01

    Ultrafast scintillators are the subject of current research in an effort to better resolve ultrafast phenomena in high-energy density physics (HEDP) experiments. Despite extensive research on new scintillator materials, the essential mechanism of energy absorption, excitation, and photo-emission has remained unchanged for over 50 years. Recently, a new class of semiconductor detector has been developed utilizing the radoptic effect, or the change of refractive index when subjected to radiation, in an attempt to record events faster than conventional scintillators.1 This study was designed for the observation of the radoptic effect by optical interferometry in different semiconductors to experimentally determine the fastest and most sensitive materials for the optimization of current radsensors.

  8. Concepts for a Standard Data Interchange Structure (SDIS) INPE proposal to CCSDS/Panel 3

    Science.gov (United States)

    Bergamini, E. W.; Martins, R. C.

    1983-05-01

    Concepts for a standard data interchange structure (SDIS) are proposed. Applications processes, products and an end-to-end reference physical and system model are identified for characterization of services to be offered with the aid of a SDIS, as a system. Implementation aspects are proposed for the SDIS: logical structure, format and protocol, inspired on the ISO/ANSI Reference Model for open systems interconnection.

  9. Optical and transport properties correlation driven by amorphous/crystalline disorder in InP nanowires

    Science.gov (United States)

    Kamimura, H.; Gouveia, R. C.; Carrocine, S. C.; Souza, L. D.; Rodrigues, A. D.; Teodoro, M. D.; Marques, G. E.; Leite, E. R.; Chiquito, A. J.

    2016-11-01

    Indium phosphide nanowires with a single crystalline zinc-blend core and polycrystalline/amorphous shell were grown from a reliable route without the use of hazardous precursors. The nanowires are composed by a crystalline core covered by a polycrystalline shell, presenting typical lengths larger than 10 μm and diameters of 80-90 nm. Raman spectra taken from as-grown nanowires exhibited asymmetric line shapes with broadening towards higher wave numbers which can be attributed to phonon localization effects. It was found that optical phonons in the nanowires are localized in regions with average size of 3 nm, which seems to have the same order of magnitude of grain sizes in the polycrystalline shell. Regardless of the fact that the nanowires exhibit a crystalline core, any considerable degree of disorder can lead to a localized behaviour of carriers. In consequence, the variable range hopping was observed as the main transport instead of the usual thermal excitation mechanisms. Furthermore the hopping length was ten times smaller than nanowire cross-sections, confirming that the nanostructures do behave as a 3D system. Accordingly, the V-shape observed in PL spectra clearly demonstrates a very strong influence of the potential fluctuations on the exciton optical recombination. Such fluctuations can still be observed at low temperature regime, confirming that the amorphous/polycrystalline shell of the nanowires affects the exciton recombination in every laser power regime tested.

  10. Alloying InAs and InP nanowires for optoelectronic applications: A first principles study

    Energy Technology Data Exchange (ETDEWEB)

    Toniolo, Giuliano R.; Anversa, Jonas [Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Santos, Cláudia L. dos [Área de Ciências Tecnológicas, Centro Universitário Franciscano, 97010-032, Santa Maria, RS (Brazil); Piquini, Paulo, E-mail: paulo.piquini@ufsm.br [Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil)

    2014-08-01

    The capability of nanowires to relieve the stress introduced by lattice mismatching through radial relaxation opens the possibility to search for devices for optoelectronic applications. However, there are difficulties to fabricate, and therefore to explore the properties of nanowires with narrow diameters. Here we apply first principles calculations to study the electronic and optical properties of narrow InAs{sub 1−x}P{sub x} nanowires. Our results show that the absorption threshold can be pushed to near-ultraviolet region, and suggests that arrays of these nanowires with different diameters and compositions could be used as devices acting from the mid-infrared to the near-ultraviolet region. - Highlights: • The optical properties of InAsP alloy nanowires were studied using DFT calculations. • The variation of band edges and band offsets with composition were determined. • The dependence of the optical absorption with alloy composition was settled. • The onset for optical absorption is suggested to be pushed to the UV region.

  11. Stability investigation for InP DHBT mm‐wave power amplifier

    DEFF Research Database (Denmark)

    Yan, Lei; Johansen, Tom Keinicke; Kammersgaard, Jacob

    2013-01-01

    microwave integrated circuit power amplifier. Experimental results from a redesigned power amplifier with improved stability are presented to confirm that the previously detected oscillation loop is removed using odd‐mode stabilization resistors with the correct choice of values and locations. © 2012 Wiley...

  12. Growth of InP Based Films Using the Hydride Growth Technique.

    Science.gov (United States)

    1981-01-01

    eliminate this variable , we are in the process of constructing a PCI3 cracking furnace, which is shown in Figure 5. The PCl3 is heated in hydrogen to such...11. The InCi, HU1, PRH P4 , and P 2equilibriuml partial pressures plotted as a funcion of the sou1rce input HI~ concentiatiofl, HCl 0 II.when TS

  13. Mid-IR optical properties of silicon doped InP

    DEFF Research Database (Denmark)

    Panah, Mohammad Esmail Aryaee; Han, Li; Norrman, Kion

    2017-01-01

    frequency were determined by Fourier transform infrared spectroscopy (FTIR) for different carrier density levels. The plasma frequency can be tuned effectively via doping from 18.43 to 50.5 THz. Based on the experimental results, a semi-empirical formula for the plasma frequency, as a function of carrier...

  14. All-optical signal processing using InP photonic-crystal nanocavity switches

    DEFF Research Database (Denmark)

    Yu, Yi; Vukovic, Dragana; Heuck, Mikkel

    2014-01-01

    the probe leads to pulse broadening. In addition, high-frequency carrier density oscillations can be induced, leading to pulse splitting. Excellent agreements between simulations and experiments are ob tained when employing a car rier rate equation model containing three relaxation times, accountin g...

  15. Evaluation of chemical phenomena that could have an effect on the performance of recirculation strainers in a Ringhals PWR; Bedoemning av kemiska fenomen med betydelse foer silfunktionen i Ringhals PWR-reaktorer

    Energy Technology Data Exchange (ETDEWEB)

    Liljenzin, Jan-Olov [Liljenzins data och kemikonsult, Goeteborg (Sweden)

    2005-01-15

    An evaluation has been made of the various chemical phenomena that could have an effect on the performance of recirculation strainers after a LOCA in a PWR. Values of pH and concentrations in the water at the bottom of the containment have been calculated as functions of time and temperature for a postulated LOCA. The behaviour of glass wool insulation, its dissolution, and precipitation of amorphous silic acid have been evaluated. Also the corrosion of galvanized surfaces has been considered. Dissolution of zinc by hot boric acid solution can lead to a later precipitation of amorphous zinc hydroxide or phosphate when pH increases and temperature drops. Also a possible growth of microorganisms is discussed. A rough classification of the various phenomena possible along a simplified time scale yields the following conclusions: Hours after the beginning of the LOCA: Precipitation of zinc hydroxide and/or phosphate. Dissolution of glass wool giving rise to an increasing concentration of silic acid in the water. Days after the beginning of the LOCA: Continued dissolution of glass wool and increasing concentration of silica in the water. Perhaps a precipitation of phosphates or carbonates of the metal ions released during dissolution of glass wool. Weeks after the beginning of the LOCA: Continued slow dissolution of glass wool leading to a risk of precipitation of amorphous silica. Perhaps a precipitation of phosphates or carbonates of the metal ions released during dissolution of glass wool. Initial growth of microorganisms in the water and on surfaces after mutations and adaptation to the existing environment. Months after the beginning of the LOCA: Continued slow dissolution of glass wool leading to a risk of precipitation of amorphous silica. Perhaps a precipitation of phosphates or carbonates of the metal ions released during dissolution of glass wool. Continued growth of adapted microorganisms.

  16. PEMBUATAN BAHAN BAKU SPREADS KAYA KAROTEN DARI MINYAK SAWIT MERAH MELALUI INTERESTERIFIKASI ENZIMATIK MENGGUNAKAN REAKTOR BATCH [Preparation of Red Palm Oil Based-Spreads Stock Rich in Carotene Through Enzymatic Interesterification in Batch-type Reactor

    Directory of Open Access Journals (Sweden)

    Nur Wulandari1,2

    2012-12-01

    Full Text Available Enzymatic interesterification of red palm oil (a mixture of red palm olein/RPO and red palm stearin/RPS in 1:1 weight ratio and coconut oil (CNO blends of varying proportions using a non-specific immobilized Candida antartica lipase (Novozyme 435 was studied for the preparation of spread stock. The interesterification reaction was held in a batch-type reactor. Two substrate blends were chosen for the production of spread stock i.e. 77.5:22,5 and 82.5:17.5 (RPO/RPS:CNO, by weight through enzymatic interesterification in three different reaction times (2, 4, and 6 hours. The interesterification reactions were conducted at 60°C, 200 rpm agitation speed and 10% of Novozyme 435. The interesterified products were evaluated for their physical characteristics (slip melting point or SMP and solid fat content or SFC and chemical characteristics (carotene retention, moisture content, and free fatty acid/FFA content. All of the interesterified products had lower SFC and SMP as compared to the initial blends. The SMP and SFC increased in longer reaction times. The SMP ranged from 30.8°C to 34.9°C. The carotene retention ranged from 74.80% to 81.08%, while the moisture content and FFA content increased in longer reaction times. The interesterified products had desirable physical properties for possible use as a spread stock rich in carotene.

  17. The development of fast reactors - Effects on the Swedish system of management of spent fuel; Utveckling av snabba reaktorer - Paaverkan paa det svenska systemet foer hantering av anvaent braensle

    Energy Technology Data Exchange (ETDEWEB)

    Hans Forsstroem, Hans [SKB International AB, Stockholm (Sweden)

    2013-09-15

    Since the start of the nuclear power era studies have been performed of how to utilise the uranium energy resource in the most effective way. Only about one percent of the energy potential of uranium is utilised in the light water reactors of today. To improve the utilization other types of reactors are needed. With fast reactors theoretically 50-100 times more energy can be extracted from the uranium. This will require reprocessing of the uranium and multiple recycling of the plutonium. Plutonium and uranium can also be recycled in light water reactors, but this will only improve the uranium utilisation by about 20 %. Recycling of plutonium on a routine basis is presently only done in France. The development of fast reactors has been going on since the end of the 1940ies. During the 1970ies the planning was that a large number of fast reactors and their associated fuel cycle facilities would be in operation by the year 2000. The development has, however, for different reasons been much slower than planned. The general assessment today is that fast reactor, if they will be realised, will hardly give an important contribution to energy production until after 2050. Nuclear power production has instead been dominated by light water reactors similar to the ones in use in Sweden. Light water reactors are believed to continue to dominate during the next decades. To start a fast reactor system plutonium (or highly enriched uranium) will be needed. Such plutonium is contained in spent nuclear fuel from light water reactors. This raises the question: Should the spent nuclear fuel be stored so that the potential energy resource in the fuel can be used in the future instead of disposing of it as a waste? The answer to this question will depend on when the material will be useful, i.e. when fast reactors have been introduced on a large scale. It will also depend on the demand for plutonium at this time, i.e. will plutonium be a scarce redundant resource at this point of time. In this context it should be considered that fast reactors will generate their own plutonium, as breeder reactors. Plutonium from other reactors will thus only be needed for the first years of operation. To provide a basis for the answer to the question if the Swedish spent fuel is a resource or a waste this report provides an overview of the present development status for fast reactors and their potential for large scale commercial use. It further describes the impact on the Swedish system for management of spent nuclear fuel if the fuel were to be reprocessed and the uranium and plutonium reused as fuel for fast reactors or for the present reactors.

  18. Nuclear power in space. Use of reactors and radioactive substances as power sources in satellites and space probes; Kaernkraft i rymden. Anvaendningen av reaktorer och radioaktiva aemnen som kraftkaellor i satelliter och rymdsonder

    Energy Technology Data Exchange (ETDEWEB)

    Hoestbaeck, Lars

    2008-11-15

    Today solar panels are the most common technique to supply power to satellites. Solar panels will work as long as the power demand of the satellite is limited and the satellite can be equipped with enough panels, and kept in an orbit that allows enough sunlight to hit the panels. There are various types of space missions that do not fulfil these criteria. With nuclear power these types of missions can be powered regardless of the sunlight and as early as 1961 the first satellite with a nuclear power source was placed in orbit. Out of seventy known space missions that has made use of nuclear power, ten have had some kind of failure. In no case has the failure been associated with the nuclear technology used. This report discusses to what degree satellites with nuclear power are a source for potential radioactive contamination of Swedish territory. It is not a discussion for or against nuclear power in space. Neither is it an assessment of consequences if radioactive material from a satellite would reach the earth's surface. Historically two different kinds of Nuclear Power Sources (NPS) have been used to generate electric power in space. The first is the reactor where the energy is derived from nuclear fission of 235U and the second is the Radioisotope Thermoelectric Generator (RTG) where electricity is generated from the heat of naturally decaying radionuclides. NPS has historically only been used in space by United States and the Soviet Union (and in one failing operation Russia). Nuclear Power Sources have been used in three types of space objects: satellites, space probes and moon/Mars vehicles. USA has launched one experimental reactor into orbit, all other use of NPS by the USA has been RTG:s. The Soviet Union, in contrast, only launched a few RTG:s but nearly forty reactors. The Soviet use of NPS is less transparent than the use in USA and some data published on Soviet systems are more or less well substantiated assessments. It is likely that also future space probes, moon and Mars vehicles will be using NPS. Besides the more established users of NPS in space, USA and Soviet Union (today Russia), it is possible that we in a not to distant future will see use of NPS in space by China, India and maybe also ESA (European Space Agency). In 1992 the United Nations General Assembly adopted a resolution regarding principles for the use of NPS in space. The resolution consists of eleven points regarding definitions and usage of NPS in space, and how to handle notification and compensation in case of damages due to a failure involving a satellite with an NPS. The probability of radioactive fallout in Sweden following an incident with a NPS-equipped satellite is very small. Due to the fact that everything placed in orbit around Earth sooner or later will re-enter, it is not possible to use probability of re-entry at any time as a measure of risk. Instead the measure Probability of re-entry within 100 year has been chosen. If the routine use of NPS in Low Earth Orbit (LEO) is not taken up again two cases can be defined: - Within about 3 000 years all satellites stored in Nuclear Safe Orbit (NSO) will de-orbit and re-enter the Earth atmosphere. One satellite, Triad OI-IX is in orbit at a lower altitude, and will thus de-orbit earlier. The probability that it does re-enter within 100 years from now is so small that a quantitative measure is deemed not to be meaningful - There is a risk of a launch failure involving a satellite or space probe with a NPS, with a risk of fallout in Sweden. This is not a large risk, but it is orders of magnitude higher than the probability of a satellite that now is in NSO will end up in Sweden within 100 years. If the routine use of NPS in LEO is re-established, the probabilities above are no longer valid

  19. Official announcement of recommendations issued by the RSK (Reactor Safety Commission) and the SSK (Radiation Protection Commission). As of 11 October 1994; Bekanntmachung von Empfehlungen der Reaktor-Sicherheitskommission und der Strahlenschutzkommission. Vom 11. Oktober 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-23

    The RSK and the SSK have found satisfactory evidence that the planned surface and underground facilities and equipment of the repository fulfill the safety requirements given, and that the planned operations for emplacement and storage can be performed with due safety. RSK and SSK put emphasis on the fact that the specific types and volumes of the radioactive wastes envisaged for storage at this site will not create a hazardous situation at any place of the entire repository as a result of temperatures, pressures or radioactivity concentrations developing during emplacement or storage, so that the repository`s hazardous potential is assessed to be very low, both in the operational phase and during the post-sealing phase. The RSK and SSK approve of the submitted safety concept for specified normal operation, as well as the submitted regime of preventive measures for protection from accidents, and the results of the accident analyses performed. Engineered and other radiation protection measures provided for specified normal operation are found to guarantee protection of the personnel, the local population and the environment. Calculated radiation doses are below the limits given in section 44, sub-section 1, and sections 45 and 49 of the Radiation Protection Ordinance (StrlSchV). The calculations submitted for emergency-induced radioactivity levels show compliance with the maximum acceptable doses laid down in section 28, sub-sec. 3 StrlSchV. The review of data submitted concerning the longterm safety of the site and the calculation approaches for determining individual doses by way of model calculations for radionuclide migration from the storage site to the biosphere are approved of by the commissions, who found evidence that the waste stored will not create hazardous radiation levels in a post-sealing operation phase extending over a period of 10.000 years. (orig./HP) [Deutsch] RSK und die SSK haben sich davon ueberzeugt, dass alle geplanten ueber- und untertaegigen Anlagen und Einrichtungen des Endlagers den sicherheitstechnischen Anforderungen entsprechen. Der geplante Einlagerungsbetrieb kann sicher durchgefuehrt werden. RSK und SSK weisen darauf hin, dass im gesamten Endlager Konrad auf Grund der spezifischen Abfalleigenschaften und der Menge an radioaktiven Abfaellen weder hohe Temperaturen oder Druecke noch hohe Aktivitaetskonzentrationen auftreten. Aus diesen Gruenden schaetzen sie das Gefaehrdungspotential des Endlagers in der Betriebs- und in der Nachbetriebsphase als sehr niedrig ein. Die RSK und die SSK akzeptieren das vorgestellte Sicherheitskonzept im bestimmungsgemaessen Betrieb sowie die getroffenen Vorsorgemassnahmen gegen Stoerfaelle und die Ergebnisse der Stoerfallanalysen. Der Strahlenschutz des Personals, der Bevoelkerung und der Umwelt ist im bestimmungsgemaessen Betrieb gewaehrleistet. Die berechneten Strahlenexpositionen liegen jeweils unter den in Paragraph 44 Abs. 1, Paragraph 45 und Paragraph 49 StrlSchV festgelegten Grenzwerten. Die Stoerfallplanungswerte gemaess Paragraph 28 Abs. 3 StrlSchV koennen eingehalten werden. Die Beratungen zur Langzeitsicherheit haben keine Einwaende gegen die Vorgehensweise zur Ermittlung der Individualdosen mittels Modellrechnungen zur Radionuklidausbreitung von der Endlagerformation bis in die Biosphaere ergeben. RSK und SSK sehen den Nachweis als erbracht an, dass in der Nachbetriebsphase im Zeitraum von ca. 10000 Jahren keine endlagerbedingte Strahlenexposition auftritt. (orig./HP)

  20. Development of a methodology for safety classification on a non-reactor nuclear facility illustrated using an specific example; Entwicklung einer Methodik zur Sicherheitsklassifizierung fuer eine kerntechnische Anlage ohne Reaktor an einem spezifischen Beispiel

    Energy Technology Data Exchange (ETDEWEB)

    Scheuermann, F.; Lehradt, O.; Traichel, A. [NUKEM Technologies Engineering Services GmbH, Alzenau (Germany)

    2015-07-01

    To realize the safety of personnel and environment systems and components of nuclear facilities are classified according to their potential danger into safety classes. Based on this classification different demands on the manufacturing quality result. The objective of this work is to present the standardized method developed by NUKEM Technologies Engineering Services for the categorization into the safety classes restricted to Non-reactor nuclear facilities (NRNF). Exemplary the methodology is used on the complex Russian normative system (four safety classes). For NRNF only the lower two safety classes are relevant. The classification into the lowest safety class 4 is accordingly if the maximum resulting dose following from clean-up actions in case of incidents/accidents remains below 20 mSv and the volume activity restrictions of set in NRB-99/2009 are met. The methodology is illustrated using an example. In short the methodology consists of: - Determination of the working time to remove consequences of incidents, - Calculation of the dose resulting from direct radiation and due to inhalation during these works. The application of this methodology avoids over-conservative approaches. As a result some previously higher classified equipment can be classified into the lower safety class.

  1. NPP Grafenrheinfeld. No thank you. Questions and answers concerning the oldest operating crack susceptible reactor in the federal republic; AKW Grafenrheinfeld. Nein danke. Fragen und Antworten zum aeltesten noch laufenden und rissanfaelligsten Reaktor der Republik

    Energy Technology Data Exchange (ETDEWEB)

    Darge, Tobias

    2014-03-15

    The brochure discusses questions on the NPP Grafenrheinfeld. concerning the following issues: reactor type, operating company, nuclear fuel, licensing, radioactive waste management, susceptibility to damage, stress test results, critical arguments concerning the reactor pressure vessel steel and the containment, cracks in the primary circuit, safety in case of an aircraft crash, possibility of a severe accident, consequences of a severe accident, medical emergency plan, public information for an emergency case, shutdown at the end of 2015, necessity of a new power plant for energy security?.

  2. Enhancement of EMAG: A 2-D Electrostatic and Magnetostatic Solver for MATLAB

    Science.gov (United States)

    1994-09-01

    insidc(N+2:2*N,:), inside(2*N+2 :3 *N,:); inside(3 *N+2:4*N,:)]; insideppW[inside( 1,:); inside(N+I ,:); inside(2*N+I,:); inside(3*N+ 1,:)]; [ rinp ...c-inp]=size(insidep); sysmat(l1:r inp,r inp+lI:r-inp+c-inp)=insidep; sysmat(lI : rinp , 1: : rinp )=-eye(r-inp); if EM-flag==M’N, er -matrix-coarse~holdCr...inside(3*N+ 1,:)1; [r-inp,c-inp]=size(insidep); sysmat(l 1 : rinp ,r inp+l1:r inp+c-inp)=insidep; sysmat(lI:r-inp, I :r_inp)=--eye(r-inp); if EM-flag=M

  3. Study of element uptake in plants from the soil to assess environmental contamination by toxic elements

    CERN Document Server

    En, Z; Tsipin, V V; Tillaev, T; Jumaniyazova, G I

    2003-01-01

    Uptake of various elements by plants through the root system from the soil was studied. Vegetation experiments with cotton and white beet were carried out in the control and test fields. The test fields were enriched with phyto-bacterial strains capable of dissolving insoluble phosphate compounds. Analytical work involved analysis of blank, control and test soil samples and analysis of plants sampled in different growing periods: periods of first sprouts, florescence and ripening of the plants. Multielement analyses of soil and plant samples were carried out by instrumental neutron activation techniques using our WWR-SM research reactor. Results of the measurements have shown that macro- and microelement composition of the analyzed soil samples were consistent to clark contents except for copper. Our experiments have resulted that the concentration levels of copper in the soils were within 300-450 mg/kg, and its average concentration in cotton leaves was about similar to 35 mg/kg while in beet leaves it reach...

  4. Electrochemical Characterization of InP and GaAs Based Structures for Space Solar Cell Applications.

    Science.gov (United States)

    Faur, Maria; Faur, Mircea; Jenkins, Philip P.; Goradia, Manju; Wilt, David M.

    1994-01-01

    In this paper the emphasis is on accurate majority carrier concentration EC-V profiling of structures based on Indium Phosphide and Gallium Arsenide, using a newly developed electrolyte based on Hydrogen Flouride, Acetic Acid, Phosphoric Acid, 1-phenyl-2-propanamine and Ammonia Diflouride. Some preliminary data on the use of this electrolyte for determining the energy distribution of surface and deep states of these structures, applicable to fabrication process optimization and radiation induced defects studies of solar cells, are also provided.

  5. Influence of Zn Diffusion on Bandwidth and Extinction in MQW Electroabsorption Modulators Buried with Semi-Insulating InP

    Institute of Scientific and Technical Information of China (English)

    Takayuki; Yamanaka; Hideki; Fukano; Ken; Tsuzuki; Munehisa; Tamura; Ryuzo; Iga; Matsuyuki; Ogasawara; Yasuhiro; Kondo; Tadashi; Saitoh

    2003-01-01

    A comprehensive analysis of multi-quantum-well electroabsorption modulators buried with semi-insulating (SI)-InP is presented. We quantitatively demonstrate that suppression of Zn diffusion into the burying and optical core layers plays a key role in high-speed and high-extinction operation.

  6. Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

    Science.gov (United States)

    Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

    2016-09-01

    Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage.

  7. Novel InP- and GaSb-based light sources for the near to far infrared

    Science.gov (United States)

    Stephan, Sprengel; Frederic, Demmerle; Markus-Christian, Amann

    2016-11-01

    This topical review presents an overview on novel concepts for light emitting diodes (LEDs) and lasers for the near infrared to the THz regime. GaSb-based quantum well lasers are shown to be a promising concept for laser from the near to mid infrared. The GaSb-based edge-emitting lasers offer low thresholds for wavelengths ranging from about 2 to 3.7 μm. However, the development of vertical-cavity surface-emitting lasers and other advanced laser concepts is lagging behind due to material issues and complicated process technology. InP-based type-II quantum wells are an innovative concept for sources emitting in the wavelength range from 2 to 4 μm. This concept combines extended long wavelength emission with the reliable process technology of the already well-established InP-based lasers. Based on this, we present LEDs up to 3.5 μm wavelength, surface emitting lasers at 2.5 μm wavelength and edge emitting lasers up to 2.7 μm. For longer wavelengths, the so-called GaSb- and InAs-based interband cascade lasers can be used operating up to about 7 μm. The mid infrared range between 3 and 20 μm is also covered by quantum cascade lasers (QCL), which are dominating especially in the longer wavelength range above 7 μm. The far infrared reaching to the THz regime is exclusively covered by QCL. While for decades the only available semiconductor laser source for the far infrared and THz range was the direct THz QCL, recent progress demonstrated THz emission in nonlinear mid infrared QCLs. These devices are emitting THz by a nonlinear frequency conversion process, which allows operation at room temperature and beyond. Tunable THz lasers were demonstrated using both monolithic tuning mechanisms and an external cavity approach.

  8. A Comparative Thermodynamic Analysis of Impurity Incorporation in Vapor Phase Epitaxial InP and GaAs.

    Science.gov (United States)

    1983-10-31

    Crystal Growth, 8, 1971. 3. Thurmond C.D., J. Phys. Chem. Solids, 26, 1965. 4. Prausnitz J.M., Molecular Thermodynamics of Fluid-Phase Equilibrium...Methods of Reactor Analysis, Academic .. Pres’, 1964. S𔃿. Prausnitz J.M., Molecular Thermodynamics of Flui’-Phase Equilibrium, Prentice Hail, 1969. 6

  9. ULTRA-HIGH BW OPTICAL COMMUNICATION USING OXYGEN PLASMA ASSISTED InP BASED HYBRID Si LASER

    Directory of Open Access Journals (Sweden)

    PRATTAY BIN ABDUL WAHAB

    2010-12-01

    Full Text Available This paper demonstrates the development of a hybrid integration platform to build major electrically driven photonic active devices: silicon evanescent DFB lasers, silicon evanescent amplifiers, silicon evanescent waveguide photo-detectors or pre-amplified photo-detectors on a single silicon platform consisting of III-V gain layers with passive waveguide for board to board and for chip to chip optical communication for tera scale computing. The structural description proposed here may push forward the manufacturing of photonic ICs tomake high speed communicational imaginings to reality and to start a new era.

  10. Ultra-broadband Nonlinear Microwave Monolithic Integrated Circuits in SiGe, GaAs and InP

    DEFF Research Database (Denmark)

    Krozer, Viktor; Johansen, Tom Keinicke; Djurhuus, Torsten

    2006-01-01

    conversion gain with a 3 dB bandwidth of 10 GHz for SiGe and in excess of 20 GHz for GaAs processes. The concurrent LO-IF isolation is better than -25 dB, without including the improvement due to the combiner circuit. The converter circuits exhibit similar instantaneous bandwidth at IF and RF ports of ≫ 7.......5 GHz and ≫ 10 GHz for SiGe BiCMOS and GaAs MMIC, respectively. Analysis of the frequency behaviour of frequency converting devices is presented for improved mixer design. Millimeter-wave front-end components for advanced microwave imaging and communications purposes have also been demonstrated...

  11. Cell-permeable Ln(III) chelate-functionalized InP quantum dots as multimodal imaging agents.

    Science.gov (United States)

    Stasiuk, Graeme J; Tamang, Sudarsan; Imbert, Daniel; Poillot, Cathy; Giardiello, Marco; Tisseyre, Céline; Barbier, Emmanuel L; Fries, Pascal Henry; de Waard, Michel; Reiss, Peter; Mazzanti, Marinella

    2011-10-25

    Quantum dots (QDs) are ideal scaffolds for the development of multimodal imaging agents, but their application in clinical diagnostics is limited by the toxicity of classical CdSe QDs. A new bimodal MRI/optical nanosized contrast agent with high gadolinium payload has been prepared through direct covalent attachment of up to 80 Gd(III) chelates on fluorescent nontoxic InP/ZnS QDs. It shows a high relaxivity of 900 mM(-1) s(-1) (13 mM(-1 )s(-1) per Gd ion) at 35 MHz (0.81 T) and 298 K, while the bright luminescence of the QDs is preserved. Eu(III) and Tb(III) chelates were also successfully grafted to the InP/ZnS QDs. The absence of energy transfer between the QD and lanthanide emitting centers results in a multicolor system. Using this convenient direct grafting strategy additional targeting ligands can be included on the QD. Here a cell-penetrating peptide has been co-grafted in a one-pot reaction to afford a cell-permeable multimodal multimeric MRI contrast agent that reports cellular localization by fluorescence and provides high relaxivity and increased tissue retention with respect to commercial contrast agents.

  12. Composition-dependent trap distributions in CdSe and InP quantum dots probed using photoluminescence blinking dynamics

    Science.gov (United States)

    Chung, Heejae; Cho, Kyung-Sang; Koh, Weon-Kyu; Kim, Dongho; Kim, Jiwon

    2016-07-01

    Although Group II-VI quantum dots (QDs) have attracted much attention due to their wide range of applications in QD-based devices, the presence of toxic ions in II-VI QDs raises environmental concerns. To fulfill the demands of nontoxic QDs, synthetic routes for III-V QDs have been developed. However, only a few comparative analyses on optical properties of III-V QDs have been performed. In this study, the composition-related energetic trap distributions have been explored by using three different types of core/multishell QDs: CdSe-CdS (CdSe/CdS/ZnS), InP-ZnSe (InP/ZnSe/ZnS), and InP-GaP (InP/GaP/ZnS). It was shown that CdSe-CdS QDs have much larger trap densities than InP-shell QDs at higher energy states (at least 1Eg (band gap energy) above the lowest conduction band edge) based on probability density plots and Auger ionization efficiencies which are determined by analyses of photoluminescence blinking dynamics. This result suggests that the composition of encapsulated QDs is closely associated with the charge trapping processes, and also provides an insight into the development of more environmentally friendly QD-based devices.Although Group II-VI quantum dots (QDs) have attracted much attention due to their wide range of applications in QD-based devices, the presence of toxic ions in II-VI QDs raises environmental concerns. To fulfill the demands of nontoxic QDs, synthetic routes for III-V QDs have been developed. However, only a few comparative analyses on optical properties of III-V QDs have been performed. In this study, the composition-related energetic trap distributions have been explored by using three different types of core/multishell QDs: CdSe-CdS (CdSe/CdS/ZnS), InP-ZnSe (InP/ZnSe/ZnS), and InP-GaP (InP/GaP/ZnS). It was shown that CdSe-CdS QDs have much larger trap densities than InP-shell QDs at higher energy states (at least 1Eg (band gap energy) above the lowest conduction band edge) based on probability density plots and Auger ionization efficiencies which are determined by analyses of photoluminescence blinking dynamics. This result suggests that the composition of encapsulated QDs is closely associated with the charge trapping processes, and also provides an insight into the development of more environmentally friendly QD-based devices. Electronic supplementary information (ESI) available: Additional blinking traces, PL decay profile, PL spectra and fluorescence intensity lifetime distribution (FLID). See DOI: 10.1039/c5nr09291d

  13. Folate-receptor-mediated delivery of InP quantum dots for bioimaging using confocal and two-photon microscopy.

    Science.gov (United States)

    Bharali, Dhruba J; Lucey, Derrick W; Jayakumar, Harishankar; Pudavar, Haridas E; Prasad, Paras N

    2005-08-17

    A novel method for the synthesis of highly monodispersed hydrophillic InP-ZnS nanocrystals and their use as luminescence probes for live cell imaging is reported. Hydrophobic InP-ZnS nanocrystals are prepared by a new method that yields high-quality, luminescent core-shell nanocrystals within 6-8 h of total reaction time. Then by carefully manipulating the surface of these passivated nanocrystals, aqueous dispersions of folate-conjugated nanocrystals (folate-QDs) with high photostability are prepared. By use of confocal microscopy, we demonstrate the receptor-mediated delivery of folic acid conjugated quantum dots into folate-receptor-positive cell lines such as KB cells. These folate-QDs tend to accumulate in multi-vescicular bodies of KB cells after 6 h of incubation. Receptor-mediated delivery was confirmed by comparison with the uptake of these particles in folate-receptor-negative cell lines such as A549. Efficient two-photon excitation of these particles and two-photon imaging using these particles are also demonstrated. The use of these InP-ZnS nanoparticles and their efficient two-photon excitation can be potentially useful for deep tissue imaging for future in vivo studies.

  14. Single-photon emission from electrically driven InP quantum dots epitaxially grown on CMOS-compatible Si(001)

    Science.gov (United States)

    Wiesner, M.; Schulz, W.-M.; Kessler, C.; Reischle, M.; Metzner, S.; Bertram, F.; Christen, J.; Roßbach, R.; Jetter, M.; Michler, P.

    2012-08-01

    The heteroepitaxy of III-V semiconductors on silicon is a promising approach for making silicon a photonic platform. Mismatches in material properties, however, present a major challenge, leading to high defect densities in the epitaxial layers and adversely affecting radiative recombination processes. However, nanostructures, such as quantum dots, have been found to grow defect-free even in a suboptimal environment. Here we present the first realization of indium phosphide quantum dots on exactly oriented Si(001), grown by metal-organic vapour-phase epitaxy. We report electrically driven single-photon emission in the red spectral region, meeting the wavelength range of silicon avalanche photodiodes’ highest detection efficiency.

  15. Large-signal modeling of multi-finger InP DHBT devices at millimeter-wave frequencies

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Midili, Virginio; Squartecchia, Michele

    2017-01-01

    on an improved UCSD HBT model formulation avoiding an erroneous RciCbci transit-time contribution from the intrinsic collector region as found in other III-V based HBT models. The mutual heating between fingers is modeled by a thermal coupling network with parameters extracted from electro-thermal simulations...

  16. Direct Growth of High-Quality InP Layers on GaAs Substrates by MOCVD

    Directory of Open Access Journals (Sweden)

    K. F. Yarn

    2003-01-01

    group V partial pressure, growth rate and V/III ratios. A mirror-like, uniform surface and high crystal quality of the metamorphic buffer layer directly grown on a GaAs substrate can be achieved. Finally, to investigate the performance of the metamorphic microwave devices, we also fabricate the InAlAs/InGaAs metamorphic HEMT on GaAs substrates.

  17. Growth of High Quality Semi-Insulating InP Single Crystal by Suppression of Compensation Defects

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Deep level defects in as-grown and annealed SI-InP samples were investigated by thermally stimulated current spectroscopy. Correlations between electrical property, compensation ratio, thermal stability and deep defect concentration in SI-InP were revealed. An optimized crystal growth condition for high quality SI-InP was demonstrated based on the experimental results.

  18. Chemical Bonding, Interdiffusion and Electronic Structure at InP, GaAs, and Si-Metal Interfaces.

    Science.gov (United States)

    1985-10-01

    1013 (1965). 15. L. Schumann, A. Lehmann, H. Sobotta , V. Riede, U. Teschner and K. HUbner, Phys. Stat. Sol. 8110, K69 (1982). 16. H.Richter, T.E...Electrochem. Soc. 112, 1013 (1965). 16. L. Schumann, A. Lehmann, H. Sobotta , V. Riede, U. Teschner and K. HUbner, Phys. Stat. Sol. Bl10, K69 (1982). C 17. J

  19. Electrical properties of nanosized non-barrier inhomogeneities in Zn-based metal-semiconductor contacts to InP

    DEFF Research Database (Denmark)

    Clausen, Thomas; Leistiko, Otto

    1998-01-01

    We have found that the electrical properties of carriers across the metal-semiconductor interface for alloyed Zn based metallizations to n- and p-InP are dominated by nanosized non-barrier inhomogeneities. The effective area covered by the nanosized regions is a small fraction of the contact area...

  20. Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

    Science.gov (United States)

    Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

    2016-01-01

    Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage. PMID:27659796

  1. Adamkus : EU might be willing to negotiate on postponing Ignalina reactor closure

    Index Scriptorium Estoniae

    2008-01-01

    President Valdas Adamkus teatas võimalusest, et EL alustab arutelu Ignalina tuumaelektrijaama sulgemise edasilükkamisest. Uue jaama valmimise aeg pole teada ning praegune reaktor on tänu rootslaste abile turvaline

  2. Adamkus : EU might be willing to negotiate on postponing Ignalina reactor closure

    Index Scriptorium Estoniae

    2008-01-01

    President Valdas Adamkus teatas võimalusest, et EL alustab arutelu Ignalina tuumaelektrijaama sulgemise edasilükkamisest. Uue jaama valmimise aeg pole teada ning praegune reaktor on tänu rootslaste abile turvaline

  3. Põhja-Korea lubas taas jätta tuumaplaanid / Jürgen Tamme

    Index Scriptorium Estoniae

    Tamme, Jürgen

    2007-01-01

    Pekingis toimunud kuuepoolsete desarmeerimiskõneluste tulemusena on Põhja-Korea nõus andma ülevaate riigi tuumarajatistest ning alustama nende likvideerimist. 14. juulil suleti Yongbyoni tuumakeskuse reaktor. Lisa: Tuumavaidlus

  4. Modifikasi Mekanisme Koufopanos pada Kinetika Reaksi Pirolisis Ampas Tebu (Bagasse)

    OpenAIRE

    Erawati, Emi; Sediawan, Wahyudi Budi; Mulyono, Panut

    2014-01-01

    Ampas tebu merupakan produk samping dari ekstraksi gula. Ampas tebu yang dihasilkan di pabrik gula sekitar 13% dari tebu yang digiling. Tujuan penelitian ini adalah menentukan energi aktivasi dan pre-exponential factor pada persamaan kinetika reaksi pirolisis ampas tebu. Pirolisis dilakukan dalam reaktor yang terbuat dari pipa besi jenis 5737 dengan diameter 7,62 cm dan panjang 37 cm. Reaktor ini dimasukkan ke dalam furnace yang berdiameter 15,24 cm dan panjang 40 cm. Seratus lima puluh...

  5. PENGARUH NILAI BAKAR TERHADAP INTEGRITAS KELONGSONG ELEMEN BAKAR TRIGA 2000

    OpenAIRE

    K.A. Sudjatmi

    2015-01-01

    Bentuk elemen bakar reaktor TRIGA Bandung adalah silinder padat yang merupakan campuran homogen paduan uranium dan zirkonium hidrida. Pada saat reaktor beroperasi, suhu elemen bakar akan bertambah, akibatnya akan menaikan tekanan gas-gas yang ada di dalam kelongsong elemen bakar. Tekanan gas yang timbul dalam kelongsong elemen bakar merupakan penjumlahan tiga komponen tekanan yaitu tekanan akibat udara yang terperangkap antara kelongsong dengan bahan bakar, tekanan oleh gas hasil fisi yang te...

  6. DESAIN TERAS PLTN JENIS PEBBLE BED MODULAR REACTOR (PBMR) MENGGUNAKAN PAKET PROGRAM MCNP-5 PADA KONDISI BEGINNING OF LIFE

    OpenAIRE

    Ralind Re Marla; Yohannes Sardjono; Supardi Supardi

    2015-01-01

    Telah dilakukan desain teras Pembangkit Listrik Tenaga Nuklir (PLTN) untuk jenis Pebble Bed Modular Reactor (PBMR) dengan daya 70 MWe untuk keperluan proses smelter pada keadaan beginning of life (BOL). Analisis ini bertujuan untuk mengetahui persen pengkayaan, distribusi suhu dan nilai keselamatan dengan koefisien reaktivitas teras yang negatif pada reaktor jenis PBMR apabila daya reaktor 70 MWe. Analisis menggunakan program Monte Carlo N-Particle-5 (MCNP5) dan dari hasil analisis ini dihara...

  7. STUDI MODEL ALIRAN FLUIDA DAN PERPINDAHAN PANAS PADA PBMR.

    Directory of Open Access Journals (Sweden)

    Achmad Fatich Al-Qodri

    2016-11-01

    Full Text Available Reaktor tipe Pebble bed merupakan opsi yang menjanjikan untuk teknologi reaktor generasi mendatang dan memiliki potensi untuk memberikan pembangkitan listrik dengan efisiensi tinggi dan murah.Perpindahan panas reaktor ini menghadapi kendala akibat kompleksitas yang berkaitan dengan desain aliran panas.Dengan demikian, untuk mensimulasikan secara baik aliran dan perpindahan panas reaktor modular pebble bed ini memerlukan suatu model perpindahan panas yang berhubungan dengan radiasi serta konveksi dan konduksi panas.Dalam studi ini, suatu model dengan kemampuan untuk mensimulasikan aliran fluida dan perpindahan panas dalam teras reaktor modular pebble bed telah dikembangkan.Model ini diterapkan pada suatu personal computer (PC yang menggunakan program komputer Matlab r2008a Versi 7.1.Beberapa parameter penting aliran fluida dan perpindahan panas telah dipelajari, termasuk penurunan tekanan (pressure drop di teras reaktor, koefisien perpindahan panas, bilangan Nusselt, dan konduktivitas panas efektif pebble bahan bakar. Hasil yang diperoleh dari percobaan simulasi menunjukkan adanya suatu tekanan yang merata pada arah radial untuk suatu rasio diameter teras terhadap elemen bakar (D/d > 20 dan koefisien perpindahan panas meningkat seiring dengan peningkatan temperatur dan laju alir massa pendingin. Model ini dapat menjelaskan secara memadai fenomena aliran panas dan perpindahan panas dan kehilangan tekanan melalui friksi dalam PBMR tipe pebble bed.

  8. Efek Durasi Pencahayaan Pada Sistem HRAR Untuk Menurunkan Kandungan Minyak Solar Dalam Air Limbah

    Directory of Open Access Journals (Sweden)

    Dian Puspitasari

    2014-09-01

    Full Text Available Kandungan minyak di dalam air limbah industri perminyakan umumnya bersifat toksik terhadap mikroorganisme dan mengganggu proses pengolahan secara biologis. Sistem HRAR diperkirakan dapat mengatasi hambatan tersebut melalui proses fotosintesis untuk menghasilkan oksigen yang dibutuhkan mikroorganisme dalam mendegradasi senyawa hidrokarbon. Penelitian ini bertujuan mengkaji pengaruh perpanjangan waktu pencahayaan pada kemampuan HRAR dalam menurunkan kandungan minyak di dalam limbah. Variabel yang digunakan pada penelitian ini adalah variasi durasi pencahayaan dan variasi penambahan volume minyak solar yang ditambahkan ke dalam reaktor. Variasi durasi pencahayaan yang digunakan adalah pencahayaan selama 12 jam dan pencahayaan selama 24 jam. Sedangkan penambahan volume minyak solar ke dalam masing-masing reaktor adalah sebesar 346 ppm, 519 ppm dan 692 ppm. Hasil yang didapatkan dari penelitian ini adalah durasi pencahayaan selama 12 jam memiliki efek yang lebih baik terhadap penurunan konsentrasi minyak dibandingkan pencahayaan selama 24 jam. Hal ini dapat terlihat dari baiknya pertumbuhan alga dan bakteri di dalam reaktor serta tingginya penurunan konsentrasi minyak solar di dalamnya. Penurunan konsentrasi minyak solar terbaik terdapat pada reaktor dengan penambahan minyak solar sebesar 346 ppm. Pada reaktor dengan durasi pencahayaan selama 12 jam terjadi penurunan konsentrasi minyak sebesar 78,4%. Sedangkan penurunan kandungan minyak solar pada reaktor dengan durasi pencahayaan selama 24 jam adalah sebesar 73,9%.

  9. Application of ultrasonic array transducers and robotics for external inspection of reactor pressure vessels - practical experience from refuelling operations at the Kruemmel NPP in 2000; Einsatz von Ultraschall-Gruppenstrahlerprueftechniken und neuer Robotik bei der Aussenpruefung von Reaktor-Druckbehaeltern - Einsatzerfahrungen im Kernkraftwerk Kruemmel im Brennelementwechsel 2000

    Energy Technology Data Exchange (ETDEWEB)

    Eggers, H.; Hein, E.; Zwahr, B. [Hamburgische Electricitaets-Werke AG, Hamburg (Germany). Abt. Oeffentlichkeitsarbeit; Rathgeb, W.; Schirner, G. [Siemens NDT, Erlangen (Germany)

    2000-07-01

    The performance of a novel testing robot of Siemens NDT and novel testing techniques for inspection of a welded joint for longitudinal and transverse defects is described in great detail. (orig./CB) [German] Im Rahmen einer Pruefgeraetelieferung ist HEW und Siemens NDT uebereingekommen, die gesamte Prueftechnik fuer die Siedewasseraussenpruefung effizienter zu gestalten. Ziel war, mit einem voellig neuen Pruefroboter und neuer Prueftechnik eine Schweissnaht in einem Prueflauf vollstaendig auf Laengs- und Querfehler zu pruefen. Dabei sollten die Umbaumassnahmen zwischen den einzelnen Pruefbereichen, wie den Rundnaehten und den Stutzeneinschweissnaehten, sowie der Stutzenkante entfallen. Die Prueftechnik wurde auf eine moderne Gruppenstrahlerprueftechnik umgestellt. Die dabei erreichbare Pruefdichte sollte zumindest so, wie mit herkoemmlichen Pruefsystemen oder dichter sein. Grundlegende Untersuchungen wurden zur Tandemtechnik angestellt, um mit einer modifizierten Tandemtechnik, bestehend aus zwei Gruppenstrahlerpruefkoepfen, die Wanddicke des SWR-Reaktordruckbehaelters mit maximal fuenf Tandemzonen zu pruefen. (orig.)

  10. SAFIRA. Sub-project B 1.3: Development of coupled in-situ reactors and optimisation of the geochemical processes in the discharge of different in situ reactor sytems. Final report; SAFIRA. Teilprojekt B 1.3: Entwicklung von gekoppelten in situ-Reaktoren und Optimierung der geochemischen Prozesse im Abstrom von verschiedenen in situ-Reaktor-Systemen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Dahmke, A.; Schaefer, D.; Koeber, R.; Plagentz, V.

    2002-12-01

    The Bitterfeld ground water is contaminated with many different pollutants over a large area. Long-term measures like reactive barriers for purification are required. However, groundwater contaminated with multiple contaminants cannot be purified by a single reactive material; for this reason, the effectivity of combinations of different reactive materials was investigated. Of the combinations investigated, reducing iron and activated carbon connected in series was the most effective: The iron will remove the reducible chlorinated hydrocarbons, while the rest of the contaminants are adsorbed to the activated carbon. Iron and ORC was another interesting option, but the combination of iron and activated carbon was found to be the most favourable option. Until a better method is available, it is recommended to connect iron and activated carbon in parallel for removing contaminant mixtures. Directly behind reactive iron barriers (also when combined with activated carbon), the limiting values of the Freshwater Ordinance for Fe(II) and pH are exceeded. Directly behind ORC reactors, the limiting values for Mg and pH are exceeded. Investigations in the outflow of these reactive materials showed that the high pH values are buffered by contact with the aquifer material to values typical of aquifers, which usually are below the limiting values of the Freshwater Ordinance. However, as the buffer capacity of the soil is exhausted, a zone with a higher pH starts to grow in the aquifer. The growth of this zone depends on the pH and on the aquifer material. Especially in soils as found at Bitterfeld, with a high concentration of organic matter, we find long-term desorption of pollutants from the aquifer materials which will burden the purified water leaving the water treatment system and prohibit its utilization. [German] Der Grundwasserleiter im Raum Bitterfeld ist grossraeumig mit vielen verschiedenen Substanzen kontaminiert. Aufgrund der grossraeumigen Erstreckung kommen nur langfristig kostenguenstige passive Massnahmen wie reaktive Barrieren zur Sanierung in Frage. Grundwasser, das mit mehreren und unterschiedlich reagierenden Stoffen kontaminiert ist, kann jedoch nicht mit Hilfe eines einzelnen reaktiven Materials gereinigt werden, daher wurde die Effektivitaet von Kombinationen unterschiedlicher reaktiver Materialien zur Sanierung untersucht. Von den untersuchten Kombinationen erwies sich die Hintereinanderschaltung von reduzierendem Eisen und Aktivkohle als besonders effektiv. Reduzierbare chlorierte Kohlenwasserstoffe werden im Eisen entfernt, die verbleibenden Kontaminanten adsorbieren auf der Aktivkohle. Auch die Hintereinanderschaltung von Eisen und Sauerstoff abgebenden ORC, in denen ein aerober mikrobieller Abbau statt findet, ist zur Entfernung von Mischkontaminationen geeignet. Eine Kostenschaetzung zeigt, dass die Kombination von Eisen und Aktivkohle in Abhaengigkeit von der Zusammensetzung der Kontamination guenstiger als Aktivkohle allein sein kann und generell guenstiger als die Kombination von Eisen und ORC ist. Ohne ein guenstigeres Verfahren zum Einbringen von Sauerstoff in den Aquifer wird die Hintereinanderschaltung von Eisen und Aktivkohle zur Sanierung von Mischkontaminationen empfohlen. Im direkten Abstrom von reaktiven Eisenbarrieren (auch in Kombination mit Aktivkohle) sind die Grenzwerte fuer Fe(II) und pH entsprechend der Trinkwasserverordnung ueberschritten. Im Abstrom von ORC-Reaktoren werden die zulaessigen Werte fuer Mg und pH ueberschritten. Untersuchungen im Abstrom dieser reaktiven Materialien zeigen, dass die hohen pH-Werte durch den Kontakt mit dem Aquifermaterial auf Aquifer-typische Werte gepuffert werden, die ueblicherweise unter den Grenzwerten der Trinkwasserverordnung liegen. Mit Erschoepfen der Pufferkapazitaet des Bodens breitet sich jedoch eine Zone mit erhoehtem pH-Wert im Aquifer aus. Die Geschwindigkeit dieser Ausbreitung haengt vom pH-Wert und dem Aquifermaterial ab. Gerade fuer sehr Organik reiche Boeden wie in Bitterfeld wird auch eine lange anhaltende Desorption von Schadstoffen aus dem Aquifermaterial beobachtet, durch die das saubere Wasser, das die Sanierungsanlage verlaesst, wieder mit Schadstoffen beladen wird, was zu einer anhaltenden Nutzungseinschraenkung fuehrt. (orig.)

  11. Development of an improved methodology for the determination of the neutron load of the pressure vessel steel of WWER-1000 type reactors. Final report; Entwicklung einer fortgeschrittenen Methodik zur Bestimmung der Neutronenbelastung des Druckbehaeltermaterials vom Reaktor des Typs WWER-1000. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Barz, H.U.; Boehmer, B.; Konheiser, J.; Stephan, I.

    1998-05-01

    The investigations, reported on here, are aimed at the theoretical and experimental determination of the neutron exposure of the VVER-1000 reactors Balakovo-3 and Rovno-3. The overall approach, partially developed and at least improved in the frame of this project, comprises the pure calculation part, the gamma spectrometric analysis of neutron activation detectors and the comparison of experimental and theoretical results using the spectrum adjustment procedure. The approach is not restricted to neutron embrittlement but can be applied to neutron fluence problems in general. (orig./GL) [Deutsch] In diesem Projekt wurden fuer die WWER-1000 Reaktoren Balakovo-3 und Rovno-3 die Parameter der Neutronenbelastung experimentell und theoretisch bestimmt. Der vorliegende Bericht beschreibt das methodische Vorgehen, welches aus dem reinen Berechnungsteil, der gammaspektrometrischen Analyse der Ativierungsdetektoren und dem Vergleich der gemessenen und berechneten Werte einschliesslich der Spektrumsjustierung besteht. Dieses Instrumentarium, welches allgemein bei der Bestimmung der Neutronenfluenz anwendbar ist, wurde im Projektzeitraum weiter verbessert. (orig./GL)

  12. SAFIRA. Sub-project B 1.3: Development of coupled in-situ reactors and optimisation of the geochemical processes in the discharge of different in situ reactor sytems. Final report; SAFIRA. Teilprojekt B 1.3: Entwicklung von gekoppelten in situ-Reaktoren und Optimierung der geochemischen Prozesse im Abstrom von verschiedenen in situ-Reaktor-Systemen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Dahmke, A.; Schaefer, D.; Koeber, R.; Plagentz, V.

    2002-12-01

    The Bitterfeld ground water is contaminated with many different pollutants over a large area. Long-term measures like reactive barriers for purification are required. However, groundwater contaminated with multiple contaminants cannot be purified by a single reactive material; for this reason, the effectivity of combinations of different reactive materials was investigated. Of the combinations investigated, reducing iron and activated carbon connected in series was the most effective: The iron will remove the reducible chlorinated hydrocarbons, while the rest of the contaminants are adsorbed to the activated carbon. Iron and ORC was another interesting option, but the combination of iron and activated carbon was found to be the most favourable option. Until a better method is available, it is recommended to connect iron and activated carbon in parallel for removing contaminant mixtures. Directly behind reactive iron barriers (also when combined with activated carbon), the limiting values of the Freshwater Ordinance for Fe(II) and pH are exceeded. Directly behind ORC reactors, the limiting values for Mg and pH are exceeded. Investigations in the outflow of these reactive materials showed that the high pH values are buffered by contact with the aquifer material to values typical of aquifers, which usually are below the limiting values of the Freshwater Ordinance. However, as the buffer capacity of the soil is exhausted, a zone with a higher pH starts to grow in the aquifer. The growth of this zone depends on the pH and on the aquifer material. Especially in soils as found at Bitterfeld, with a high concentration of organic matter, we find long-term desorption of pollutants from the aquifer materials which will burden the purified water leaving the water treatment system and prohibit its utilization. [German] Der Grundwasserleiter im Raum Bitterfeld ist grossraeumig mit vielen verschiedenen Substanzen kontaminiert. Aufgrund der grossraeumigen Erstreckung kommen nur langfristig kostenguenstige passive Massnahmen wie reaktive Barrieren zur Sanierung in Frage. Grundwasser, das mit mehreren und unterschiedlich reagierenden Stoffen kontaminiert ist, kann jedoch nicht mit Hilfe eines einzelnen reaktiven Materials gereinigt werden, daher wurde die Effektivitaet von Kombinationen unterschiedlicher reaktiver Materialien zur Sanierung untersucht. Von den untersuchten Kombinationen erwies sich die Hintereinanderschaltung von reduzierendem Eisen und Aktivkohle als besonders effektiv. Reduzierbare chlorierte Kohlenwasserstoffe werden im Eisen entfernt, die verbleibenden Kontaminanten adsorbieren auf der Aktivkohle. Auch die Hintereinanderschaltung von Eisen und Sauerstoff abgebenden ORC, in denen ein aerober mikrobieller Abbau statt findet, ist zur Entfernung von Mischkontaminationen geeignet. Eine Kostenschaetzung zeigt, dass die Kombination von Eisen und Aktivkohle in Abhaengigkeit von der Zusammensetzung der Kontamination guenstiger als Aktivkohle allein sein kann und generell guenstiger als die Kombination von Eisen und ORC ist. Ohne ein guenstigeres Verfahren zum Einbringen von Sauerstoff in den Aquifer wird die Hintereinanderschaltung von Eisen und Aktivkohle zur Sanierung von Mischkontaminationen empfohlen. Im direkten Abstrom von reaktiven Eisenbarrieren (auch in Kombination mit Aktivkohle) sind die Grenzwerte fuer Fe(II) und pH entsprechend der Trinkwasserverordnung ueberschritten. Im Abstrom von ORC-Reaktoren werden die zulaessigen Werte fuer Mg und pH ueberschritten. Untersuchungen im Abstrom dieser reaktiven Materialien zeigen, dass die hohen pH-Werte durch den Kontakt mit dem Aquifermaterial auf Aquifer-typische Werte gepuffert werden, die ueblicherweise unter den Grenzwerten der Trinkwasserverordnung liegen. Mit Erschoepfen der Pufferkapazitaet des Bodens breitet sich jedoch eine Zone mit erhoehtem pH-Wert im Aquifer aus. Die Geschwindigkeit dieser Ausbreitung haengt vom pH-Wert und dem Aquifermaterial ab. Gerade fuer sehr Organik reiche Boeden wie in Bitterfeld wird auch eine lange anhaltende Desorption von Schadstoffen a

  13. THERMAL-HYDRAULIC ANALYSIS OF SMR WITH NATURALLY CIRCULATING PRIMARY SYSTEM DURING LOSS OF FEED WATER ACCIDENT

    Directory of Open Access Journals (Sweden)

    Susyadi Susyadi

    2016-09-01

    ABSTRAK Reaktor daya kecil modular (SMR memiliki beberapa keunggulan dibanding reaktor daya besar konvensional. Dengan disain yang lebih sederhana dan terintegrasi, penerapan hukum alamiah untuk sistem keselamatannya dan biaya modal yang rendah, reaktor ini sangat cocok untuk dibangun di Indonesia. Salah satunya disain SMR yang sedang dikembangkan menerapkan gaya penggerak alami untuk sistim pendingin primernya. Dengan disain seperti itu, adalah sangat penting untuk memahami implikasinya terhadap aspek keselamatan pada seluruh kondisi operasi. Salah satu yang perlu diinvestigasi adalah kecelakaan kehilangan air umpan (LoFW. Pada studi ini, dilakukan analisis kinerja thermal hidrolik SMR yang menggunakan sistim pendinginan primer sirkulasi alam saat kecelakaan LoFW. Tujuannya adalah untuk menginvestigasi karakteristik aliran sistem primer saat kecelakaan LoFW dan untuk memastikan apakah aliran sirkulasi alam cukup untuk memindahkan panas dari teras guna menjaga kondisi tetap aman selama kecelakaan tersebut. Metoda yang digunakan adalah dengan merepresentasikan sistem reaktor ke dalam model-model generik program RELAP5 dan melakukan simulasi numerik. Hasil perhitungan menunjukkan bahwa setelah kejadian pemicu dan trip reaktor, pada sisi primer laju alirnya berfluktuasi secara signifikan dan temperatur pendinginnya menurun secara bertahap sedangkan  pada sisi sekunder kondisi uap berubah menjadi uap jenuh. Laju alir turun dari ~711 kg/detik menjadi ~263 kg/detik sebelum kembali naik lagi pada t=~46 detik. Saat laju alir di titik terendah, temperatur pusat bahan bakar dan fluida pendingin adalah sekitar  ~565 K dan  ~554 K, yang menujukkan bahwa temperatur bahan bakar masih jauh di bawah batas disain dan temperatur fluidanya juga berada di bawah titik saturasi. Keadaan ini menunjukkan bahwa saat transien kedua parameter utama termohidrolik reaktor tetap dalam kondisi yang dapat diterima sehingga dapat disimpulkan  bahwa saat  kecelakaan kehilangan air umpan, SMR

  14. Electronic parameters of high barrier Au/Rhodamine-101/n-Inp Schottky diode with organic Latin-Small-Letter-Dotless-I nterlayer

    Energy Technology Data Exchange (ETDEWEB)

    Guellue, Oe. [Batman University, Faculty of Sciences and Arts, Department of Physics, Batman (Turkey); Aydogan, S., E-mail: saydogan@atauni.edu.tr [Atatuerk University, Faculty of Sciences, Department of Physics, 25240-Erzurum (Turkey); Tueruet, A. [Atatuerk University, Faculty of Sciences, Department of Physics, 25240-Erzurum (Turkey)

    2012-01-01

    In this work, we present that Rhodamine-101 (Rh-101) organic molecules can control the electrical characteristics of conventional Au/n-InP metal-semiconductor contacts. An Au/n-InP Schottky junction with Rh-101 interlayer has been formed by using a simple cast process. A potential barrier height as high as 0.88 eV has been achieved for Au/Rh-101/n-InP Schottky diodes, which have good current-voltage (I-V) characteristics. This good performance is attributed to the effect of formation of interfacial organic thin layer between Au and n-InP. By using capacitance-voltage measurement of the Au/Rh-101/n-InP Schottky diode the diffusion potential and the barrier height have been calculated as 0.78 V and 0.88 eV, respectively. From the I-V measurement of the diode under illumination, short circuit current and open circuit voltage have been extracted as 1.70 {mu}A and 240 mV, respectively.

  15. Quasiparticle and excitonic effects in the optical spectra of diamond, SiC, Si, GaP, GaAs, InP, and AlN

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, P.H.; Seino, K.; Schmidt, W.G.; Furthmueller, J.; Bechstedt, F. [Institut fuer Festkoerpertheorie und -optik, Friedrich-Schiller-Universitaet, Max-Wien-Platz 1, 07743 Jena (Germany)

    2005-11-01

    We demonstrate the potential of recently developed electronic-structure methods for the calculation of the optical properties of solids. As prototypical examples semiconductors crystallizing in diamond or zinc-blende structure are studied. The many-body effects are fully taken into account by a solution of the combined Dyson and Bethe-Salpeter equations. We show that an initial-value formulation of the polarization function allows for an efficient numerical calculation of the optical susceptibility. The effect of the renormalization of electrons and holes to quasiparticles is shown for both the band structure and the optical spectrum. In addition, excitonic effects are identified to remarkably influence the optical absorption. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Shadowing and mask opening effects during selective-area vapor-liquid-solid growth of InP nanowires by metalorganic molecular beam epitaxy.

    Science.gov (United States)

    Kelrich, A; Calahorra, Y; Greenberg, Y; Gavrilov, A; Cohen, S; Ritter, D

    2013-11-29

    Indium phosphide nanowires were grown by metalorganic molecular beam epitaxy using the selective-area vapor-liquid-solid method. We show experimentally and theoretically that the size of the annular opening around the nanowire has a major impact on nanowire growth rate. In addition, we observed a considerable reduction of the growth rate in dense two-dimensional arrays, in agreement with a calculation of the shadowing of the scattered precursors. Due to the impact of these effects on growth, they should be considered during selective-area vapor-liquid-solid nanowire epitaxy.

  17. MOCVD regrowth of InP on RIE patterned substrates for p-substrate 1.3{micro}m BH laser application

    Energy Technology Data Exchange (ETDEWEB)

    Takemi, M.; Kimura, T.; Suzuki, D.; Shiba, T.; Shibata, K.; Mihashi, Y.; Takamiya, S.; Aiga, M. [Mitsubishi Electric Corp., Itami, Hyogo (Japan). Optoelectronic and Microwave Devices Lab.

    1996-12-31

    The authors have investigated the growth behavior of sulfur-doped n-InP layers around the dry-etched mesas as a function of various H{sub 2}S flow rates. It is found that the growth rate of n-InP layer of the sidewall ((1{bar 1}0) plane) of the mesa is significantly affected by the H{sub 2}S flow rate. Using this technique, the authors have fabricated p-substrate 1.3{micro}m BH laser with a pnp current-blocking structure around the dry-etched mesa and realized excellent lasing characteristics with high reliability for the first time.

  18. Tuning InP self-assembled quantum structures to telecom wavelength: A versatile original InP(As) nanostructure "workshop"

    Science.gov (United States)

    Mura, E. E.; Gocalinska, A.; Juska, G.; Moroni, S. T.; Pescaglini, A.; Pelucchi, E.

    2017-03-01

    The influence of hydride exposure on previously unreported self-assembled InP(As) nanostructures is investigated, showing an unexpected morphological variability with growth parameters, and producing a large family of InP(As) nanostructures by metalorganic vapour phase epitaxy, from dome and ring-like structures to double dot in a ring ensembles. Moreover, preliminary microphotoluminescence data are indicating the capped rings system as an interesting candidate for single quantum emitters at telecom wavelengths, potentially becoming a possible alternative to InAs QDs for quantum technology and telecom applications.

  19. Cytotoxicity assessment of functionalized CdSe, CdTe and InP quantum dots in two human cancer cell models.

    Science.gov (United States)

    Liu, Jing; Hu, Rui; Liu, Jianwei; Zhang, Butian; Wang, Yucheng; Liu, Xin; Law, Wing-Cheung; Liu, Liwei; Ye, Ling; Yong, Ken-Tye

    2015-12-01

    The toxicity of quantum dots (QDs) has been extensively studied over the past decade. Some common factors that originate the QD toxicity include releasing of heavy metal ions from degraded QDs and the generation of reactive oxygen species on the QD surface. In addition to these factors, we should also carefully examine other potential QD toxicity causes that will play crucial roles in impacting the overall biological system. In this contribution, we have performed cytotoxicity assessment of four types of QD formulations in two different human cancer cell models. The four types of QD formulations, namely, mercaptopropionic acid modified CdSe/CdS/ZnS QDs (CdSe-MPA), PEGylated phospholipid encapsulated CdSe/CdS/ZnS QDs (CdSe-Phos), PEGylated phospholipid encapsulated InP/ZnS QDs (InP-Phos) and Pluronic F127 encapsulated CdTe/ZnS QDs (CdTe-F127), are representatives for the commonly used QD formulations in biomedical applications. Both the core materials and the surface modifications have been taken into consideration as the key factors for the cytotoxicity assessment. Through side-by-side comparison and careful evaluations, we have found that the toxicity of QDs does not solely depend on a single factor in initiating the toxicity in biological system but rather it depends on a combination of elements from the particle formulations. More importantly, our toxicity assessment shows different cytotoxicity trend for all the prepared formulations tested on gastric adenocarcinoma (BGC-823) and neuroblastoma (SH-SY5Y) cell lines. We have further proposed that the cellular uptake of these nanocrystals plays an important role in determining the final faith of the toxicity impact of the formulation. The result here suggests that the toxicity of QDs is rather complex and it cannot be generalized under a few assumptions reported previously. We suggest that one have to evaluate the QD toxicity on a case to case basis and this indicates that standard procedures and comprehensive protocols are urgently needed to be developed and employed for fully assessing and understanding the origins of the toxicity arising from different QD formulations.

  20. Large-scale synthesis of high quality InP quantum dots in a continuous flow-reactor under supercritical conditions

    Science.gov (United States)

    Ippen, Christian; Schneider, Benjamin; Pries, Christopher; Kröpke, Stefan; Greco, Tonino; Holländer, Andreas

    2015-02-01

    The synthesis of indium phosphide quantum dots (QDs) in toluene under supercritical conditions was carried out in a macroscopic continuous flow reaction system. The results of first experiments are reported in comparison with analogous reactions in octadecene. The reaction system is described and details are provided about special procedures that are enabled by the continuous flow system for the screening of reaction conditions. The produced QDs show very narrow emission peaks with full width at half maximum down to 45 nm and reasonable photoluminescence quantum yields. The subsequent purification process is facilitated by the ease of removal of toluene, and the productivity of the system is increased by high temperature and high pressure conditions.

  1. Influence of optical coherence on the electron spin in singly charged InP quantum dots excited by resonant laser pulses

    Science.gov (United States)

    Tomimoto, Shinichi; Kawana, Keisuke; Murakami, Akira; Masumoto, Yasuaki

    2012-06-01

    We have experimentally studied the spin dynamics of excitons, electrons, and trions in charge-tunable InP/InGaP quantum dots (QDs) excited by picosecond resonant laser pulses by observing the time-resolved Kerr rotation. In singly charged QDs, inversion of the spin polarization direction of doped electrons is found to be caused simply by variation in the pulse intensity, which is accompanied by an abrupt change of the spin coherence time. This phenomenon is reproduced by density-matrix calculations allowing for the reaction on the QD electron-trion four-level system during its coherent radiation emission. This result means that the optical coherence is another critical factor affecting electron spin coherence.

  2. 胶体化学法合成InP量子点%Synthesis of InP Quantum Dots by Colloidal Chemical Processing

    Institute of Scientific and Technical Information of China (English)

    吴启明; 张道礼; 张建兵; 陈胜

    2006-01-01

    采用InCl3·4H2O为铟源,P(Si(CH3)3)3为磷源,TOPO为包覆剂,十二烷胺为表面活性剂,通过胶体化学法合成InP量子点.使用TEM对量子点表面形貌进行了分析,利用荧光光谱仪和紫外可见分光光度计分析了其光学性质.所合成的量子点具有较好的分散性和表面性能,随着粒径的减小,表现出较好的量子效应.量子点表面性能的好坏是影响其光学性能的一个关键因素.

  3. All-Optical Regenerative OTDM Add-Drop Multiplexing at 40 Gb/s using Monolithic InP Mach-Zehnder Interferometer

    DEFF Research Database (Denmark)

    Fischer, St.; Dülk, M.; Gamper, E.;

    2000-01-01

    We present a novel method for all-optical add-drop multiplexing having regenerative capability for 40-Gb/s optical time-division multiplexed (OTDM) data using a semiconductor optical amplifier (SOA) based, monolithic Mach-Zehnder interferometer (MZI). Simultaneous dropping of one 10-Gb/s channel ...

  4. All-Optical Regenerative OTDM Add/Drop Multiplexing at 40 Gbit/s using Monolithic InP Mach-Zehnder Interferometer

    DEFF Research Database (Denmark)

    Buxens, Alvaro A.; Clausen, Anders; Poulsen, Henrik Nørskov;

    2000-01-01

    We report a novel method for simultaneous add-drop multiplexing in OTDM systems which includes regenerative capabilities and perfect clearing of the drop channel time slot. The principle has been demonstrated at 40 Gb/s showing an excellent performance....

  5. Passive and electro-optic polymer photonics and InP electronics integration for multi-flow terabit transceivers at edge SDN switches and data-center gateways

    DEFF Research Database (Denmark)

    Avramopoulos, Hercules; Katopodis, V.; Groumas, P.

    2014-01-01

    Within PANTHER research project, we aim to develop multi-rate, multi-format, multi-reach and multi-flow terabit transceivers for data-center gateways, having the capability of flexibly controlling this enormous capacity and distributing it among independent optical flows. To this end, we combine ...

  6. Perancangan dan Simulasi MRAC untui Proses Pengendalian Temperatur pada Continuous Stirred Tank Reactor (CSTR

    Directory of Open Access Journals (Sweden)

    Amelia Sylvia

    2014-03-01

    Full Text Available Temperatur merupakan salah satu variabel proses dasar yang dikendalikan untuk menjaga suhu cairan di dalam reaktor. Model Reference Adaptive Controller (MRAC dengan MIT rule dipilih untuk mencapai spesifikasi respon yang diinginkan pada CSTR. Beban yang bervariasi berupa debit aliran likuid yang masuk ke dalam reaktor dapat menyebabkan perubahan parameter yang mempengaruhi perubahan temperatur output produk pada CSTR. Sebuah simulasi dilakukan dengan menggunakan MATLAB dan hasilnya dianalisa. Respon plant dapat melakukan adaptasi parameter – parameter kontrolernya cukup baik pada nilai gain adaptasi dengan rentang 0.00000010000 sampai 0.00000000001. Waktu yang dibutuhkan untuk mengatasi beban yang bervariasi berupa debit aliran yang masuk ke dalam reaktor dengan nilai yang maksimal (1.5 m^3/min menghasilkan respon plant lebih cepat 42 detik dari pada debit aliran masuk dengan nilai yang nominal (1 m^3/min 63 detik dan minimal (0.5 m^3/min 75 detik.

  7. Preclinical studies of neutron capture therapy effectiveness in the treatment of malignant tumours, at the nuclear reactor hvr-sm InP as of RUz Preclinical studies of neutron capture therapy effectiveness in the treatment of malignant tumours, at the nuclear reactor hvr-sm InP as of RUz

    OpenAIRE

    KHODJAEVA NAZIMA KHAYRULLAEVNA; NAVRUZOV SARIMBEK NAVRUZOVICH; KAHHOROV JAMAL NEMATOVICH; KULABDULLAEV GAYRAT ASATOVICH; КIM ANDREY ALEKSEEVICH

    2016-01-01

    Developed for treatment of radio resistant malignant tumors the Gadolinium neutron capture therapy (GdNCT) is based on the nuclear capture and reactions that occur when 155Gd and 157Gd, which are non-radioactive constituents of natural elemental gadolinium, are irradiated by thermal neutrons with low energy, In this article, results of scientific researches on development GdNCT in Uzbekistan are presented. The beam of epithermal neutrons with characteristics satisfying the all requirements of...

  8. Pengolahan Sampah Secara Pirolisis dengan Variasi Rasio Komposisi Sampah dan Jenis Plastik

    Directory of Open Access Journals (Sweden)

    Qonita Rachmawati

    2015-03-01

    Full Text Available Pada tahun 2012, sampah yang dihasilkan sebesar 1200 ton/hari. Jika permasalahan sampah di Kota Surabaya tidak ditangani dengan baik maka akan menimbulkan beberapa masalah antara lain: masalah kesehatan dan masalah kebersihan. Oleh karena itu, diperlukan metode yang dapat mengolah sampah namun tidak menimbulkan masalah baru lainnya. Salah satu metode pengolahan sampah yang telah dikembangkan, yaitu metode pirolisis. Penelitian ini bertujuan untuk menentukan pengaruh jenis plastik dan komposisi terhadap produk hasil pirolisis. Pada penelitian ini digunakan reaktor dengan kapasitas 500 g yang berbahan stainless steel. Variabel yang digunakan yaitu jenis sampah plastik dan komposisi sampah. Jenis sampah yang digunakan yaitu sampah plastik HDPE (High Density Polyethylene, PET (Poly Ethylene Terephthalate, dan PS (Poly Styrene. Komposisi sampah yang digunakan antara lain: 100:0, 75:25, dan 50:50. Temperatur yang digunakan pada reaktor yaitu 500°C dengan waktu 30 menit. Penelitian dimulai dari persiapan bahan uji, persiapan reaktor, percobaan pendahuluan, dan penelitian dengan reaktor pirolisis. Selanjutnya dilakukan analisis untuk masing-masing hasil produk. Penelitian ini jenis sampah plastik yang menghasilkan gas tertinggi yaitu jenis plastik PET sebesar 45,40% dan jenis plastik yang menghasilkan wax tertinggi yaitu jenis plastik HDPE sebesar 69,91%. Sedangkan komposisi yang menghasilkan gas tertinggi yaitu komposisi dengan ranting 25% dan PET 75% sebesar 71,24% dan komposisi yang menghasilkan wax tertinggi yaitu komposisi dengan ranting 25% dan PS 75% sebesar 61,36%.

  9. Kinetika Reaksi Heterogen Etanolisis Minyak Jarak Kepyar (Ricinus communis) dengan Katalisator Zeolit Klinoptilolit

    OpenAIRE

    Harjanti, Ratna Sri; Sarto

    2012-01-01

    Minyak jarak kepyar mempunyai potensi untuk dijadikan biodiesel melalui proses alkoholisis katalitik. Zeolit alam klinoptilolit berpotensi digunakan sebagai katalisator dalam alkoholisis tersebut. Pada penelitian ini, alkoholisis minyak jarak dilakukan pada suhu tinggi dengan katalisator zeolit alam klinoptilolit dalam sebuah reaktor autoklaf yang dilengkapi dengan manometer, termometer, kran pengambil cuplikan, dan pemanas. Data percobaan menunjukkan bahwa pada kisaran waktu tertentu, pening...

  10. Electrophysiologic study of dysrhythmias after atrial operations in dogs.

    Science.gov (United States)

    Tamiya, T; Yamashiro, T; Hata, A; Kuge, K; Asano, S; Sato, T

    1992-10-01

    Experiments were conducted with 159 dogs to investigate the mechanism of persistent dysrhythmias clinically encountered after atrial-level operations. Those found after incisions to the internodal pathways (INPs) of the right atrium were analyzed using cardiac mapping in an anesthetized or extracorporeally perfused state. Longitudinal incisions of the posterior INP often allowed inducible sustained atrial flutter, with circus movement of excitation around the right atrium near the tricuspid orfice. Sustained atrial flutter thus produced was modified in cycle length by coexisting division of the middle INP but inhibited by that of the anterior INP. Its incidence increased at chronic stage, with marked cicatricial changes. The disrupted anterior INP markedly prolonged conduction time to the atrioventricular node and A-H interval compared with the other disruptions. Persistent atrioventricular junctional rhythm developed in about 50% of the animals after disruption of all three INPs or anterior and posterior INPs; division of the anterior INP was the common potent factor, although no single blocked INP produced persistent junctional rhythm. Our results support the "summation theory." The incidence of junctional rhythm and hypoxia of the sinoatrial node (flow rate of less than 10 mL.100 g-1.min-1) were markedly enhanced by coexisting blockade of atrial feeding arteries in addition to division of the anterior INP. In conclusion, massive posterior INP disruption is a potent anatomic substrate in producing sustained atrial flutter, middle INP division a modifier, and anterior INP division an inhibitor. Division of the anterior INP is a potent anatomic substrate in producing junctional rhythm, and hypoxia involving the sinoatrial node reacts as its synergic factor.

  11. MBE Growth of High 2-DEG Sheet Density InP Based PHEMT Epitaxial Materials%MBE生长高2-DEG面密度InP基PHEMT外延材料

    Institute of Scientific and Technical Information of China (English)

    徐静波; 杨瑞霞; 武一宾

    2005-01-01

    利用MBE技术生长了InP基InAlAs/InGaAs PHEMT结构,使用原子力显微镜(AFM)、霍耳测试系统研究了影响二维电子气(2-DEG)面密度和电子迁移率的因素,着重分析了隔离层厚度、沟道层In组分的影响.在保持较高迁移率的基础上,生长出了高μn×ns的InP PHEMT外延材料.

  12. Analysis by high-resolution electron microscopy of elastic strain in thick InAs layers embedded in Ga{sub 0.47}In{sub 0.53}As buffers on InP(0 0 1) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Gatel, C., E-mail: gatel@cemes.fr [CNRS, CEMES (Centre d' Elaboration des Materiaux et d' Etudes Structurales), BP 94347, 29 rue J. Marvig, 31055 Toulouse (France)] [Universite de Toulouse, UPS, 31055 Toulouse (France); Tang, H.; Crestou, C.; Ponchet, A. [CNRS, CEMES (Centre d' Elaboration des Materiaux et d' Etudes Structurales), BP 94347, 29 rue J. Marvig, 31055 Toulouse (France)] [Universite de Toulouse, UPS, 31055 Toulouse (France); Bertru, N.; Dore, F.; Folliot, H. [FOTON-LENS-INSA, 20 av. des Buttes de Coesmes, CS 14315, 35043 Rennes (France)

    2010-05-15

    Elastic strain has been investigated by transmission electron microscopy in nanometric InAs layers grown on Ga{sub 0.47}In{sub 0.53}As/InP(0 0 1) by molecular beam epitaxy using a residual Sb flux. Deposits of 10 and 15 monolayers of InAs (3 and 4.5 nm) remain elastically stressed with a two-dimensional growth mode. The out-of-plane strain in the layers is analyzed by cross-sectional high-resolution electron microscopy. A distortion of the substrate below and on top of the InAs layers is detected and is attributed to a significant surface relaxation effect due to thinning. Surface relaxation is modeled by three-dimensional finite element modeling. An additional relaxation effect is obtained when the sample is not infinite along the direction perpendicular to the thinning. This effect enhances the buffer distortion of the buffers below and on top of the strained layers. Taking into account thin foil effects, the experimental out-of-plane strain is in excellent agreement with the theoretical value calculated for a pure InAs layer (i.e. 0.035), demonstrating the high level of strain and stress in the layers.

  13. Influence of baking on the photoluminescence spectra of In{sub 1-x} Ga{sub x} As{sub y} P{sub 1-y} solid solutions grown on Inp substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mishurnyi, V.A.; Gorbatchev, A.Y.; Anda, F. De; Nieto N, J. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi (Mexico)

    2004-07-01

    The influence of thermal treatments on the photoluminescence spectra of In{sub 1-x} Ga{sub x} As{sub y} P{sub 1-y} epitaxial layers of various compositions grown by LPE on In P substrates has been studied. To prevent the epitaxial layers from degradation, due to phosphor evaporation during the baking, their surface was covered by spin-on SiO{sub 2} layers. The photoluminescence spectra did not change for solid solutions whose compositions were near In P and InGaAs. For compositions in the middle of the lattice-matched region, the variations were very noticeable because the appearance of additional peaks in the luminescence spectra. This could be related to the decomposition of those solid solutions whose compositions lie inside a theoretically predicted miscibility gap. (Author)

  14. Effect of InxGa1-xAs Interlayer on Surface Morphology and Optical Properties of GaSb/InGaAs Type-II Quantum Dots Grown on InP (100) Substrates

    Science.gov (United States)

    Chen, Yu-Long; Gao, You; Chen, Hong; Zhang, Hui; He, Miao; Li, Shu-Ti; Zheng, Shu-Wen

    2016-09-01

    Not Available Supported by the Science and Technology Planning Projects of Guangdong Province under Grant Nos 2014B050505020, 2015B010114007 and 2014B090904045, the Research Fund for the Doctoral Program of Higher Education of China under Grant No 20134407110008, the Guangzhou Science and Technology Project of Guangdong Province under Grant No 2016201604030027, and the Zhongshan Science and Technology Project of Guangdong Province under Grant No 2013B3FC0003.

  15. Study on Thin Film Growth of InP in H2SO4 Etchants%硫酸蚀刻溶液中InP半导体之薄膜生长

    Institute of Scientific and Technical Information of China (English)

    刘汉忠

    2013-01-01

    利用X-射线衍射技术研究了InP半导体在H2SO4/H2O蚀刻溶液中之薄膜生长,分析p型InP(100)在酸性蚀刻溶液中表面氧化物的化学组成.实验中,一台12 kW的铜旋转阳极X射线源用于保证高敏感度的表面型态分析.利用广角度衍射(WAD),从一个基体氧化物的晶格组界面检测衍射线来分析蚀刻溶液H2SO4/H2O.每个衍射线出现可能引起的反应物表面层反射光束的干涉图案,生成物为具有单晶结构的磷酸铟水合物(InPO4·xH2O).观察到一组(nh,nk,hi)的广角度衍射中磷酸铟水合物(InPO4· xH2O)相的反射峰,并且侦测到在每个反射光束的干扰振荡现象.利用感应电浆耦合离子发射光谱法测定溶液中的铟(In)和磷(P)成分,分析InP在不同浓度的H2SO4 /H2O溶液中的溶解速率.观察发现,在InP的氧化表面上存在混合成份的氧化物和单一成份生成物.借着ICP仪器分析测试在照光或暗室下,InP在H2SO4/H2O系统的溶解率差异几乎是不可分辨的.藉由X射线结果对比JCPDS卡标准化合物中的数据.可获得酸性溶液蚀刻反应中各种表面氧化物的结构特点和反应现象.

  16. Time-resolved photoluminescence measurements of InGaAs/ InP multiple-quantum-well structures at 1.3-µm wavelengths by use of germanium single-photon avalanche photodiodes.

    Science.gov (United States)

    Buller, G S; Fancey, S J; Massa, J S; Walker, A C; Cova, S; Lacaita, A

    1996-02-20

    A commercially available germanium avalanche photodiode operating in the single-photon-counting mode has been used to perform time-resolved photoluminescence measurements on InGaAs/lnP multiple-quantum-well structures. Photoluminescence in the spectral region of 1.3-1.48 µm was detected with picosecond timing accuracy by use of the time-correlated single-photon counting technique. The carrier dynamics were monitored for excess photogenerated carrier densities in the range 10(18)-10(15) cm(-3). The recombination time is compared for similar InGaAs-based quantum-well structures grown by use of different epitaxial processes.

  17. Monolithic integration of an InGaAsP InP strained DFB laser and an electroabsorption modulator by ultra-low-pressure selective-area-growth MOCVD

    Science.gov (United States)

    Zhao, Q.; Pan, J. Q.; Zhou, F.; Wang, B. J.; Wang, L. F.; Wang, W.

    2005-06-01

    The design and basic characteristics of a strained InGaAsP-InP multiple-quantum-well (MQW) DFB laser monolithically integrated with an electroabsorption modulator (EAM) by ultra-low-pressure (22 mbar) selective-area-growth (SAG) MOCVD are presented. A fundamental study of the controllability and the applicability of band-gap energy by using the SAG method is performed. A large band-gap photoluminescence wavelength shift of 88 nm was obtained with a small mask width variation (0-30 µm). The technique is then applied to fabricate a high performance strained MQW EAM integrated with a DFB laser. The threshold current of 26 mA at CW operation of the device with DFB laser length of 300 µm and EAM length of 150 µm has been realized at a modulator bias of 0 V. The devices also exhibit 15 dB on/off ratio at an applied bias voltage of 5 V.

  18. Evaluation of Some Agroecological Characteristics of Basil (Ocimum basilicum L. as Affected by Simultaneous Application of Water-Saving Superabsorbent Hydrogel in Soil and Foliar Application of Humic Acid under Different Irrigation Intervals in a Low Inp

    Directory of Open Access Journals (Sweden)

    M. Jahan

    2016-02-01

    Full Text Available Introduction: Basil (Ocimum basilicum L. is an annual herbaceous plant that belongs to lamiaceae family. This plant is native of India country and other countries in south of Asia. Nowadays, the use of water superabsorbent polymers is increased in agriculture and their role in reducing the drought stress and increasing the crops production has been demonstrated in many researches. Superabsorbent polymers can absorb lots of water and keep it in their structure and give it to plant under drought stress conditions (9. Humic substances are a group of heterogeneous molecules that are bonded together by weak forces, therefore they have high chemical stability. Humic acid comprise 65 to 80 percent of total soil organic matter (6. According to medicinal importance of Basil and its roles in the food and pharmaceutical industries, beside the limited water resources and need to increase water use efficiency through using ecological inputs, this study designed and conducted aimed to evaluate agroecological characteristics of Basil as affected by application of water-saving superabsorbent and humic acid under irrigation intervals. Materials and Methods: In order to evaluate the effects of different amounts of water-saving superabsorbent and foliar application of humic acid and irrigation intervals on some quantitative characteristics of basil (Ocimum basilicum L., a split strip plot experiment was conducted based on RCBD design with three replications at The Research Farm of Ferdowsi University of Mashhad, Iran during growing season of 2012-13. Experimental factors included three levels of water-saving superabsorbent (0, 40 and 80 kg ha-1 as the main plot factor, two levels of humic acid (0 and 3 kg ha-1 as the sub plot factor and two levels of irrigation interval (5 and 10 days as the strip plot factor. Studied traits were seed number and weight per plant, plant height, number of lateral branches per plant, seed yield, biological yield and harvest index. Results and Discussion: The results showed that interaction of superabsorbent and humic acid had a significant effect on seed yield (p≤ 0.05, as the highest seed yield (2638.8 kg ha-1 obtained from application of 40 kg ha-1 superabsorbent without humic acid. Evaluation of the superabsorbent and irrigation intervals interaction revealed that in all levels of superabsorbent, dry matter yield under irrigation interval of 5 days was more than irrigation interval of 10 days, so that dry matter yield at irrigation interval of 5 days and 0, 40 and 80 kg ha-1 levels of superabsorbent increased 13, 50 and 17% compared to irrigation interval of 10 days, respectively. Seed number per plant significantly was affected by interaction effects of humic acid and irrigation interval, so that in condition of using of humic acid in irrigation interval of 10 days, seed number per plant increased by 26% compared to control. The triple interaction of superabsorbent, humic acid and irrigation interval had significant effect on branch number per plant, as in irrigation interval of 5 days, in both conditions of application and no-application of humic acid, the highest branch number per plant observed in 40 kg ha-1 level of superabsorbent. In general, the combined use of 40 kg ha-1 water-saving superabsorbent and humic acid in different levels of irrigation, particularly under drought stress condition, while improved quantitative characteristics of basil, played an effective role in alleviation the devastating effects of drought stress. It seems that the appropriate level of water-saving superabsorbent (40 kg ha-1 increased morphological characteristics and seed yield of Basil through the absorption of water (4 and improvement of soil physical characteristics. It seems that humic acid increased quantitative characteristics of Basil by increasing activity of growth hormones such as auxin and improving nutrient uptake. In most of the studied traits, efficiency of humic acid improved in conditions of superabsorbent application and the plant could use the humic acid more efficient. Conclusio

  19. Size-resolved measurements of ice nucleating particles at six locations in North America and one in Europe

    Science.gov (United States)

    Mason, R. H.; Si, M.; Chou, C.; Irish, V. E.; Dickie, R.; Elizondo, P.; Wong, R.; Brintnell, M.; Elsasser, M.; Lassar, W. M.; Pierce, K. M.; Leaitch, W. R.; MacDonald, A. M.; Platt, A.; Toom-Sauntry, D.; Sarda-Estève, R.; Schiller, C. L.; Suski, K. J.; Hill, T. C. J.; Abbatt, J. P. D.; Huffman, J. A.; DeMott, P. J.; Bertram, A. K.

    2015-07-01

    Detailed information on the size of ice nucleating particles (INPs) may be useful in source identification, modeling their transport in the atmosphere to improve climate predictions, and determining how effectively or ineffectively instrumentation used for quantifying INPs in the atmosphere captures the full INP population. In this study we report immersion-mode INP number concentrations as a function of size at six ground sites in North America and one in Europe. The lowest INP number concentrations were observed at Arctic and alpine locations and the highest at suburban and agricultural locations, consistent with previous studies of INP concentrations in similar environments. We found that 91, 79, and 63 % of INPs had an aerodynamic diameter > 1 μm at ice activation temperatures of -15, -20, and -25 °C, respectively, when averaging over all sampling locations. In addition, 62, 55, and 42 % of INPs were in the coarse mode (> 2.5 μm) at ice activation temperatures of -15, -20, and -25 °C, respectively, when averaging over all sampling locations. These results are consistent with six out of the seven studies in the literature that have focused on the size distribution of INPs in the atmosphere. Taken together, these findings strongly suggest that supermicron and coarse mode aerosol particles are a significant component of the ice nuclei population in many different ground-level environments. Further size-resolved studies of INPs as a function of altitude are required.

  20. Novel dimeric β-helical model of an ice nucleation protein with bridged active sites

    Directory of Open Access Journals (Sweden)

    Walker Virginia K

    2011-09-01

    Full Text Available Abstract Background Ice nucleation proteins (INPs allow water to freeze at high subzero temperatures. Due to their large size (>120 kDa, membrane association, and tendency to aggregate, an experimentally-determined tertiary structure of an INP has yet to be reported. How they function at the molecular level therefore remains unknown. Results Here we have predicted a novel β-helical fold for the INP produced by the bacterium Pseudomonas borealis. The protein uses internal serine and glutamine ladders for stabilization and is predicted to dimerize via the burying of a solvent-exposed tyrosine ladder to make an intimate hydrophobic contact along the dimerization interface. The manner in which PbINP dimerizes also allows for its multimerization, which could explain the aggregation-dependence of INP activity. Both sides of the PbINP structure have tandem arrays of amino acids that can organize waters into the ice-like clathrate structures seen on antifreeze proteins. Conclusions Dimerization dramatically increases the 'ice-active' surface area of the protein by doubling its width, increasing its length, and presenting identical ice-forming surfaces on both sides of the protein. We suggest that this allows sufficient anchored clathrate waters to align on the INP surface to nucleate freezing. As PbINP is highly similar to all known bacterial INPs, we predict its fold and mechanism of action will apply to these other INPs.

  1. Joint Services Electronics Program.

    Science.gov (United States)

    1986-09-30

    Generalized Impulse Response," Proceedings of Midwest Symposium on Circuits and Systems, Puebla , Mexico, pp. 198-202 (August 15-16, 1983). 10. S.H. Park...properties include basic studies of ambient /InP interactions and studies of the properties of various interfaces between lnP and deposited dielectrics...Investigations of InP surfaces include studies of the interaction of InP with chemical etching solutions, gas ambients , and vacuum environments. Studies

  2. Size-resolved measurements of ice-nucleating particles at six locations in North America and one in Europe

    Science.gov (United States)

    Mason, R. H.; Si, M.; Chou, C.; Irish, V. E.; Dickie, R.; Elizondo, P.; Wong, R.; Brintnell, M.; Elsasser, M.; Lassar, W. M.; Pierce, K. M.; Leaitch, W. R.; MacDonald, A. M.; Platt, A.; Toom-Sauntry, D.; Sarda-Estève, R.; Schiller, C. L.; Suski, K. J.; Hill, T. C. J.; Abbatt, J. P. D.; Huffman, J. A.; DeMott, P. J.; Bertram, A. K.

    2016-02-01

    Detailed information on the size of ice-nucleating particles (INPs) may be useful in source identification, modeling their transport in the atmosphere to improve climate predictions, and determining how effectively or ineffectively instrumentation used for quantifying INPs in the atmosphere captures the full INP population. In this study we report immersion-mode INP number concentrations as a function of size at six ground sites in North America and one in Europe using the micro-orifice uniform-deposit impactor droplet freezing technique (MOUDI-DFT), which combines particle size-segregation by inertial impaction and a microscope-based immersion freezing apparatus. The lowest INP number concentrations were observed at Arctic and alpine locations and the highest at suburban and agricultural locations, consistent with previous studies of INP concentrations in similar environments. We found that 91 ± 9, 79 ± 17, and 63 ± 21 % of INPs had an aerodynamic diameter > 1 µm at ice activation temperatures of -15, -20, and -25 °C, respectively, when averaging over all sampling locations. In addition, 62 ± 20, 55 ± 18, and 42 ± 17 % of INPs were in the coarse mode (> 2.5 µm) at ice activation temperatures of -15, -20, and -25 °C, respectively, when averaging over all sampling locations. These results are consistent with six out of the nine studies in the literature that have focused on the size distribution of INPs in the atmosphere. Taken together, these findings strongly suggest that supermicron and coarse-mode aerosol particles are a significant component of the INP population in many different ground-level environments. Further size-resolved studies of INPs as a function of altitude are required since the size distribution of INPs may be different at high altitudes due to size-dependent removal processes of atmospheric particles.

  3. Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

    Science.gov (United States)

    Mason, R. H.; Si, M.; Li, J.; Chou, C.; Dickie, R.; Toom-Sauntry, D.; Pöhlker, C.; Yakobi-Hancock, J. D.; Ladino, L. A.; Jones, K.; Leaitch, W. R.; Schiller, C. L.; Abbatt, J. P. D.; Huffman, J. A.; Bertram, A. K.

    2015-11-01

    Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between -15 and -25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between -15 and -25 °C at this site for the time period studied. At -30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving chemical tracers of marine aerosols and marine biological activity, sodium and methanesulfonic acid, indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated. This finding illustrates that additional measurements are needed to improve parameterizations of INPs and their

  4. Basic Research of Self-Organized Quantum Dots and Their Potential In Solar Cells and Novel Devices Applications (Phase 4)

    Science.gov (United States)

    2006-01-01

    addition, InP quantum dots are also another candidate for high efficiency quantum dot solar cells due to their wider bandgap which gives better response...at visible region of solar spectrum. However, novel epitaxial growth of high density InP quantum dots with appropriate capping layers is needed to...improvement. We are looking forward to studying InP quantum dots for new structure of quantum dot molecule solar cells having higher open- circuit voltage

  5. ACAPEX – Ship-Based Ice Nuclei Collections Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    DeMott, Paul J [Colorado State Univ., Fort Collins, CO (United States); Hill, Thomas CJ [Colorado State Univ., Fort Collins, CO (United States)

    2016-04-01

    Measurements were sought to evaluate a hypotheses that sea-spray-sourced ice-nucleating particles (INPs) are of biological origin and represent a distinctly different INP population in comparison to long-range-transported desert or urban and regional land-sourced INP, and that the layering of marine within other aerosol layers feeding orographic storms over the mountains of California and the Western United States thereby leads to common and quantifiable scenarios that influence precipitation over the region. Aerosol collections on the National Oceanic and Atmospheric Administration (NOAA) research vessel (RV) Ronald H. Brown, for subsequent processing of INP immersion freezing activation temperature spectra and composition analyses, added a valuable measurement component to the ARM Cloud Aerosol Precipitation Experiment (ACAPEX) and related CalWater2 (NOAA) studies for use in parameterizing and modeling the impacts of marine boundary layer and other aerosols on climate and radiation via aerosol indirect effects on mixed-phase clouds. Twenty-five nominally 24-hour collections were made and have been processed for immersion freezing INP number concentrations versus temperature in the mixed-phase cloud temperature regime from -10 to -27°C. The similarity of INP number concentrations compared to typical marine boundary layer values attributed to sea-spray aerosols was noted. Nevertheless, variability of INP concentrations of up to 50 times was noted at individual temperatures over the course of the study. A particular analysis possible with this data set is to examine INP budgets over oceans inside versus outside of atmospheric river conditions. These INP measurements supplemented multiple airborne INP measurements on the ARM Aerial Facility (AAF), and others on the ground during ACAPEX and CalWater2, to provide extensive spatial and temporal analyses of INP immersion freezing spectra during winter storm periods. Future analyses will use thermal sensitivity to

  6. Pengolahan Limbah Rumah Makan dengan Proses Biofilter Aerobik

    Directory of Open Access Journals (Sweden)

    Laily Zoraya Zahra

    2015-03-01

    Full Text Available Berkembangnya rumah makan/restoran yang semakin pesat dapat dipastikan akan turut menambah buangan air limbah domestik dengan kadar organik yang tinggi dalam jumlah yang tidak sedikit yang dibuang ke badan air.Tingginya kadar organik dalam limbah domestik rumah makan akan menyebabkan aroma yang tidak sedap jika tidak ada pengolahan terlebih dahulu, maka pengolahan yang dapat digunakan untuk mengolah air limbah rumah makan tersebut adalah proses biofilter aerobik. Penelitian dilakukan dengan proses biofilter aerobik dengan aliran downflow dan menggunakan sistem intermitten.Variabel dalam penelitian ini adalah media biofilter berupa kerikil dan batu alam serta Hydraulic Retention Time (HRT 8 jam. Parameter pencemar yang diukur efisiensinya adalah BOD, COD, dan TSS. Besarnya penyisihan parameter BOD, COD dan TSS dengan menggunakan biofilter aerob berturut-turut mencapai 94,83%, 92,95%, dan 95%. Reaktor paling baik dalam mengolah air limbah adalah reaktor biofilter dengan media kerikil pada HRT 8 jam.

  7. Size-resolved measurements of ice nucleating particles at North American and European sites

    Science.gov (United States)

    Mason, R.; Si, M.; Chou, C.; Irish, V.; Dickie, R.; Elizondo, P.; Wong, R.; Brintnell, M.; Elsasser, M.; Lassar, W.; Pierce, K.; Leaitch, W. R.; Macdonald, A. M.; Platt, A.; Desiree, T. S.; Sarda Esteve, R.; Schiller, C. L.; Suski, K. J.; Hill, T. C. J.; Abbatt, J.; Huffman, J. A.; DeMott, P. J.; Bertram, A. K.

    2015-12-01

    Ice nucleating particles (INPs) are a small fraction of the total aerosol population capable of catalyzing ice formation under atmospheric conditions, and may therefore influence the albedo and lifetime of mixed-phase and ice clouds. Compared to ambient measurements of the total number concentration of INPs, relatively little data exists on the size distribution of INPs in the atmosphere. Information on the size of INPs may be useful in source identification, modeling their transport in the atmosphere, and determining the degree to which common INP instrumentation captures the full atmospheric INP population. Measured using the micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT), we report immersion-mode INP number concentrations as a function of particle size at ground-level sites in North America and Europe, including Arctic, alpine, coastal, marine, agricultural, and suburban environments. On average, more than 91 % of INPs active at -15 °C were found to be supermicron in size and 62 % were in the coarse mode (> 2.5 μm). While these percentages decreased with decreasing freezing temperature, many INPs remained in the supermicron with nearly half of those active at -25 °C belonging to the coarse mode.

  8. Down-expression of tumor protein p53-induced nuclear protein 1 in human gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Pei-Hong Jiang; Yoshiharu Motoo; Stéphane Garcia; Juan Lucio Iovanna; Marie-Josèphe Pébusque; Norio Sawabu

    2006-01-01

    AIM: Overexpression of tumor protein p53-induced nuclear protein 1 (TP53INP1) induces G1 cell cycle arrest and increases p53-mediated apoptosis. To clarify the clinical importance of TP53INP1, we analyzed TP53INP1and p53 expression in gastric cancer.METHODS: TP53INP1 and p53 expression were examined using immunohistochemistry in 142 cases of gastric cancer. The apoptosis of gastric cancer cells was analyzed using the TUNEL method. The relationship between the expression of TP53INP1 and clinicopathological factors was statistically analyzed.RESULTS: TP53INP1 was expressed in 98% (139/142cases) of non-cancerous gastric tissues and was downexpressed in 64% (91/142 cases) of gastric cancer lesions from the same patients. TP53INP1 expression was significantly decreased (43.9%) in poorly differentiated adenocarcinoma compared with well or moderately differentiated adenocarcinoma (81.6%).Cancers invading the submucosa or deeper showed lower positively (59.1%) compared with mucosal cancers (85.2%). Decrease or loss of TP53INP1 expression was significantly correlated with lymphatic invasion (54.3%vs 82.0% without lymphatic invasion) and node-positive patients (31.3% vs 68.3% in node-negative patients).P53 was expressed in 68 (47.9%) patients of gastric cancer, whereas it was absent in normal gastric tissues.A significant association was also observed between TP53INP1 status and the level of apoptosis in tumor cells: the apoptotic index in TP53INP1-positive tissues was significantly higher than that in TP53INP1-negative portions. Finally, when survival data were analyzed,loss of TP53INP1 expression had a significant effect in predicting a poor prognosis (P= 0.0006).CONCLUSION: TP53INP1-positive rate decreases with the progression of gastric cancer. TP53INP1 protein negativity is significantly associated with aggressive pathological phenotypes of gastric cancer. TP53INP1is related to the apoptosis of gastric cancer cells. The decreased expression of the TP53INP1 protein may

  9. Pra Desain Pabrik Sorbitol dari Tepung Tapioka dengan Hidrogenasi Katalitik

    Directory of Open Access Journals (Sweden)

    Hellen Kartika Dewi

    2014-03-01

    Full Text Available Sorbitol yang dikenal juga sebagai glusitol, adalah suatu gula alkohol yang dimetabolisme lambat di dalam tubuh. Sorbitol banyak digunakan sebagai bahan baku untuk industri barang konsumsi dan makanan seperti pasta gigi, permen, kosmetika, farmasi, vitamin C, termasuk industri tekstil dan kulit. Pembuatan sorbitol dari bahan baku tepung tapioka. Pabrik sorbitol ini direncanakan akan didirikan di Propinsi Jawa Tengah tepatnya di Kabupaten Batang dengan kapasitas produksi 30.000 ton/tahun. Proses produksi Sorbitol menggunakan proses hidrogenasi katalitik. Pembuatan sorbitol dari bahan baku pati melalui dua tahap proses utama yaitu proses perubahan starch menjadi glukosa melalui hidrolisa double enzym. Enzim yang digunakan yaitu α-amylase dan glukoamylase. Proses hidrogenasi katalitik dilakukan dengan mereaksikan larutan dekstrose dan gas hidrogen bertekanan tinggi dengan menambahkan katalis nikel dalam reaktor (Reaktor Hidrogenasi. Gas hidrogen masuk dari bawah reaktor secara bubbling dan larutan dekstrose diumpankan dari atas reaktor sehingga kontak yang terjadi semakin baik. Sorbitol yang di hasilkan dalam pradesain pabrik sorbitol ini dengan konsentrasi 58,2%. Pendirian pabrik sorbitol memerlukan biaya investasi modal tetap (fixed capital sebesar Rp 168.801.192.952, modal kerja (working capital  Rp 29.788.445.815, investasi total Rp 198.589.638.767, Biaya produksi per tahun Rp 368.832.813.809 dan  hasil penjualan per tahun Rp 540.000.078.750. Dari analisa ekonomi didapatkan BEP sebesar 26,32%. ROI sesudah pajak 48,5 %, POT sesudah pajak 2,14 tahun. Dari segi teknis dan ekonomis, pabrik ini layak untuk didirikan.

  10. DESAIN TERAS PLTN JENIS PEBBLE BED MODULAR REACTOR (PBMR MENGGUNAKAN PAKET PROGRAM MCNP-5 PADA KONDISI BEGINNING OF LIFE

    Directory of Open Access Journals (Sweden)

    Ralind Re Marla

    2015-03-01

    Full Text Available Telah dilakukan desain teras Pembangkit Listrik Tenaga Nuklir (PLTN untuk jenis Pebble Bed Modular Reactor (PBMR dengan daya 70 MWe untuk keperluan proses smelter pada keadaan beginning of life (BOL. Analisis ini bertujuan untuk mengetahui persen pengkayaan, distribusi suhu dan nilai keselamatan dengan koefisien reaktivitas teras yang negatif pada reaktor jenis PBMR apabila daya reaktor 70 MWe. Analisis menggunakan program Monte Carlo N-Particle-5 (MCNP5 dan dari hasil analisis ini diharapkan dapat memenuhi syarat dalam mendukung program percepatan pembangunan kelistrikan batubara 10.000 MWe khususnya untuk proses smelter, yang tersebar merata di wilayah Indonesia. Hasil penelitian menunjukkan bahwa, faktor perlipatan efektif (k-eff Reaktor jenis PBMR daya 70 MWe mengalami kondisi kritis pada pengkayaan 5,626 % dengan nilai faktor perlipatan efektif 1,00031±0,00087 dan nilai koefisien reaktivitas suhu pada -10,0006 pcm/K. Dari hasil analisis daat disimpulkan bahwa reaktor jenis PBMR daya 70 MWe adalah aman.   ABSTRACT The core design of Nuclear Power Plant for Pebble Bed Modular Reactor (PBMR type with 70 MWe capacity power in Beginning of Life (BOL has been performed. The aim of this analysis, to know percent enrichment, temperature distribution and safety value by negative temperature coefficient at type PBMR if reactor power become lower equal to 70 MWe. This analysis was expected become one part of overview project development the power plant with 10.000 MWe of total capacity, spread evenly in territory of Indonesia especially to support of smelter industries. The results showed that, effective multiplication factor (keff with power 70 MWe critical condition at enrichment 5,626 %is 1,00031±0,00087, based on enrichment result, a value of the temperature coefficient reactivity is - 10,0006 pcm/K. Based on the results of these studies, it can beconcluded that the PBMR 70 MWe design is theoritically safe.

  11. PENGOLAHAN AIR LIMBAH INDUSTRI TEH BOTOL DENGAN TEKNOLOGI BIOLOGIS ANAEROBIK UASB – WETLAND

    Directory of Open Access Journals (Sweden)

    Misbachul Moenir

    2014-11-01

    Full Text Available Industri minuman ringan merupakan salah satu industri yang mengeluarkan air limbah dengan beban organik yang cukup tinggi. Sistem pengolahan air limbah yang berkategori low rate seperti sistem activated sludge yang sekarang diterapkan di industri kurang sesuai lagi untuk mengolah air limbah yang mengandung cemaran organik tinggi dan bersifat kompleks terlarut. Sistem Up-flow Anaerobic Sludge Blanket (UASB adalah salah satu proses anaerobik dengan efisiensi tinggi yang dapat beroperasi pada beban organik tinggi. Proses pengolahan dengan wetland sebagai pengolahan lanjutan dapat menurunkan kadar cemaran organik lebih lanjut. Pada penelitian digunakan air limbah yang berasal dari salah satu industri teh botol di Jawa Tengah. Sumber mikroba anaerob yang digunakan sebagai seeding reaktor UASB (2 unit paralel berasal dari lumpur anaerob yang terbentuk pada pengolahan air limbah industri tahu yang telah berfungsi dengan baik. Waktu tinggal dalam reaktor UASB secara total selama 19 jam dengan debit 2.297 l/hari. Pengolahan lanjutan dari reaktor UASB dilakukan dengan pengolahan wetlandHasil penelitian menunjukkan bahwa reaktor UASB I dan II dapat mereduksi COD dengan efisiensi tertinggi 88,51% dan pengolahan dengan wetland tertinggi 85,02%, selanjutnya pengolahan air limbah dengan kombinasi UASB dan wetland dapat mereduksi beban cemaran COD antara 97,65 – 98,90 %  dan hasil effluen sudah memenuhi baku mutu air limbah industri minuman dalam botol menurut Peraturan Daerah Provinsi Jawa Tengah Nomor 5 Tahun 2012,  yaitu COD = 35,44 mg/l, TSS = 16 mg/l, dan BOD5 = 13,44 mg/l.

  12. Konstrukce uzávěru s tuhnutím pracovní látky

    OpenAIRE

    ZEMAN, Radek

    2013-01-01

    Tato bakalářská práce se zabývá praktickým návrhem uzávěru s tuhnutím pracovní látky pro jaderná zařízení z hlediska výpočtového i konstrukčního. Úvodem jsou stručně popsány technologie jaderných reaktorů na rychlých neutronech a reaktorů s palivem rozpuštěným v taveninách fluoridových solí. Autor zdůrazňuje výhody jejich použití, díky kterým se mohou v budoucnu stát důležitou součástí jaderné energetiky. Pracovní látky použité pro výpočet jsou převzaty z těchto reaktorů – kapalný sodík a smě...

  13. ANALISA KARAKTERISTIK MINYAK PLASTIK HASIL DUA KALI PROSES PIROLISIS

    Directory of Open Access Journals (Sweden)

    Untung Surya Dharma

    2015-06-01

    Full Text Available Limbah plastik dapat dimanfaatkan sebagai bahan baku minyak plastik dengan menggunakan proses pirolisis. Minyak plastik yang dihasilkan dapat dimanfaatkan sebagai zat aditif atau campuran bahan bakar pada mesin. Pada Penelitian ini, proses pembuatan minyak plastik menggunakan dua kali proses pirolisis. Suhu reaktor pada proses pirolisis yang pertama dan kedua berbeda berturut-turut yaitu 200 oC dan 150 oC. Dari hasil penelitian ini diketahui bahwa pada proses pirolisis pertama dengan suhu reaktor 200 oC, dari 25 kg bahan baku menghasilkan 15,5 liter minyak plastik dalam waktu 80 jam. Sedangkan pada proses pirolisis kedua dengan suhu reaktor 150 oC, dari 15 liter minyak plastik dari hasil proses pirolisis pertama menghasilkan 11,6 liter minyak plastik dalam waktu 3,33 Jam. Adapun karakter minyak plastik yang dihasilkan adalah massa jenis 771,4 kg/m3, Viskositas 0,501 m2/s dan Nilai kalor 10518 kJ/kg

  14. Penurunan Logam Timbal (Pb pada Limbah Cair TPA Piyungan Yogyakarta dengan Constructed Wetlands Menggunakan Tumbuhan Eceng Gondok (Eichornia Crassipes

    Directory of Open Access Journals (Sweden)

    Eko Siswoyo

    2015-10-01

    Full Text Available Salah satu permasalahan lingkungan yang ditimbulkan dari adanya lindi di TPA Piyungan yaitu pencemaran pada badan air, sungai dan air tanah. Untuk mengatasi permasalahan ini salah satunya dengan sistem Constructed Wetlands dengan menggunakan tumbuhah eceng gondok. Tujuan dari penelitian ini adalah untuk mengetahui tingkat penurunan konsentrasi Timbal (Pb yang terdapat dalam limbah cair TPA Piyungan dengan Constructed Wetlands menggunakan tumbuhan eceng gondok dan untuk mengetahui seberapa besar kapasitas serapan tumbuhan eceng gondok terhadap kandungan Timbal (Pb dalam limbah cair TPA Piyungan.Dalam penelitian ini digunakan reaktor yang terbuat dari kayu yang dilapisi plastik dengan ukuran 0,5 m x 1,0 m. Setiap reaktor diberi media tanah 5 cm, dan diberi tumbuhan sebanyak 14 buah. Reaktor tersebut diberi perlakuan dengan konsentrasi limbah yang bervariasi (100%, 75%, 50%, 25%, dan 0%, dan waktu pengambilan sampel (0, 3, 6, 9, 12 hari. Dengan menggunakan metode SSA (Spektrofotometri Serapan Atom.Berdasarkan pengujian diperoleh bahwa penurunan logam Pb pada limbah cair TPA Piyungan hari ke- 12, yaitu sebesar 0.0501mg/L pada konsentrasi 100%, 0.0295mg/L pada konsentrasi 75%, 0.0267mg/L pada konsentrasi 50% dan 0.0041 mg/L pada konsentrasi 25%.

  15. Jaderná paliva pro tlakovodní jaderné reaktory

    OpenAIRE

    Smetana, Jan

    2014-01-01

    Tato bakalářská práce se zabývá konstrukčními vlastnostmi jaderných paliv, pozornost je věnována zejména palivům pro tlakovodní reaktory. Pro lepší představu čtenáře jsou uvedeny rovněž příklady realizace jaderných paliv pro jednotlivé typy reaktorů. Ve stručnosti je uvedena historie tlakovodních reaktorů, zejména reaktorů VVER. Vývoj jaderného paliva pro tlakovodní reaktory je zde demonstrován na příkladu vývoje paliva u našich jaderných elektráren Dukovany a Temelín, důraz je kladen předevš...

  16. Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater

    Science.gov (United States)

    Irish, Victoria E.; Elizondo, Pablo; Chen, Jessie; Chou, Cédric; Charette, Joannie; Lizotte, Martine; Ladino, Luis A.; Wilson, Theodore W.; Gosselin, Michel; Murray, Benjamin J.; Polishchuk, Elena; Abbatt, Jonathan P. D.; Miller, Lisa A.; Bertram, Allan K.

    2017-09-01

    The sea-surface microlayer and bulk seawater can contain ice-nucleating particles (INPs) and these INPs can be emitted into the atmosphere. Our current understanding of the properties, concentrations, and spatial and temporal distributions of INPs in the microlayer and bulk seawater is limited. In this study we investigate the concentrations and properties of INPs in microlayer and bulk seawater samples collected in the Canadian Arctic during the summer of 2014. INPs were ubiquitous in the microlayer and bulk seawater with freezing temperatures in the immersion mode as high as -14 °C. A strong negative correlation (R = -0. 7, p = 0. 02) was observed between salinity and freezing temperatures (after correction for freezing depression by the salts). One possible explanation is that INPs were associated with melting sea ice. Heat and filtration treatments of the samples show that the INPs were likely heat-labile biological materials with sizes between 0.02 and 0.2 µm in diameter, consistent with previous measurements off the coast of North America and near Greenland in the Arctic. The concentrations of INPs in the microlayer and bulk seawater were consistent with previous measurements at several other locations off the coast of North America. However, our average microlayer concentration was lower than previous observations made near Greenland in the Arctic. This difference could not be explained by chlorophyll a concentrations derived from satellite measurements. In addition, previous studies found significant INP enrichment in the microlayer, relative to bulk seawater, which we did not observe in this study. While further studies are needed to understand these differences, we confirm that there is a source of INP in the microlayer and bulk seawater in the Canadian Arctic that may be important for atmospheric INP concentrations.

  17. Characteristics of atmospheric ice nucleating particles associated with biomass burning in the US: Prescribed burns and wildfires

    Science.gov (United States)

    McCluskey, Christina S.

    Insufficient knowledge regarding the sources and number concentrations of atmospheric ice nucleating particles (INP) leads to large uncertainties in understanding the interaction of aerosols with cloud processes, such as cloud life time and precipitation rates. This study utilizes measurements of INP from a diverse set of biomass burning events to better understand INP associated with biomass burning in the U.S. Prescribed burns in Georgia and Colorado, two Colorado wildfires and two laboratory burns were monitored for INP number concentrations. The relationship between nINP and total particle number concentrations, evident within prescribed burning plumes, was degraded within aged smoke plumes from the wildfires, limiting the utility of this relationship for comparing laboratory and field data. Larger particles, represented by n500nm, are less vulnerable to plume processing and have previously been evaluated for their relation to nINP. Our measurements indicated that for a given n500nm, nINP associated with the wildfires were nearly an order of magnitude higher than nINP found in prescribed fire emissions. Reasons for the differences between INP characteristics in these emissions were explored, including variations in combustion efficiency, fuel type, transport time and environmental conditions. Combustion efficiency and fuel type were eliminated as controlling factors by comparing samples with contrasting combustion efficiencies and fuel types. Transport time was eliminated because the expected impact would be to reduce n500nm, thus resulting in the opposite effect from the observed change. Bulk aerosol chemical composition analyses support the potential role of elevated soil dust particle concentrations during the fires, contributing to the population of INP, but the bulk analyses do not target INP composition directly. It is hypothesized that both hardwood burning and soil lofting are responsible for the elevated production of INP in the Colorado wildfires in

  18. Single quantum dot nanowire photodetectors

    NARCIS (Netherlands)

    Van Kouwen, M.P.; Van Weert, M.H.M.; Reimer, M.E.; Akopian, N.; Perinetti, U.; Algra, R.E.; Bakkers, E.P.A.M.; Kouwenhoven, L.P.; Zwiller, V.

    2010-01-01

    We report InP nanowire photodetectors with a single InAsP quantum dot as light absorbing element. With excitation above the InP band gap, the nanowire photodetectors are efficient (quantum efficiency of 4%). Under resonant excitation of the quantum dot, the photocurrent amplitude depends on the line

  19. In-Network Processing for Mission-Critical Wireless Networked Sensing and Control: A Real-Time, Efficiency, and Resiliency Perspective

    Science.gov (United States)

    Xiang, Qiao

    2014-01-01

    As wireless cyber-physical systems (WCPS) are increasingly being deployed in mission-critical applications, it becomes imperative that we consider application QoS requirements in in-network processing (INP). In this dissertation, we explore the potentials of two INP methods, packet packing and network coding, on improving network performance while…

  20. 47.8 GHz InPHBT quadrature VCO with 22% tuning range

    DEFF Research Database (Denmark)

    Hadziabdic, Dzenan; Johansen, Tom Keinicke; Krozer, Viktor;

    2007-01-01

    A 38-47.8 GHz quadrature voltage controlled oscillator (QVCO) in InP HBT technology is presented. The measured output power is - 15 dBm. The simulated phase noise ranges from -84 to -86 dBc/Hz at 1 MHz offset. It is believed that this is the first millimetre-wavc QVCO implemented in InP HBT techn...