Effect of Sn on the optical band gap determined using absorption spectrum fitting method

Energy Technology Data Exchange (ETDEWEB)

Heera, Pawan, E-mail: sramanb70@mailcity.com [Department of Physics, Himachal Pradesh University, Shimla, INDIA, 171005 (India); Govt. College Amb, Himachal Pradesh, INDIA,177203 (India); Kumar, Anup, E-mail: kumar.anup.sml@gmail.com [Department of Physics, Himachal Pradesh University, Shimla, INDIA, 171005 (India); Physics Department, Govt. College, Kullu, H. P., INDIA, 175101 (India); Sharma, Raman, E-mail: pawanheera@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla, INDIA, 171005 (India)

2015-05-15

We report the preparation and the optical studies on tellurium rich glasses thin films. The thin films of Se{sub 30}Te{sub 70-x} Sn{sub x} system for x= 0, 1.5, 2.5 and 4.5 glassy alloys prepared by melt quenching technique are deposited on the glass substrate using vacuum thermal evaporation technique. The analysis of absorption spectra in the spectral range 400nm–4000 nm at room temperature obtained from UV-VIS-NIR spectrophotometer [Perkin Elmer Lamda-750] helps us in the optical characterization of the thin films under study. The absorption spectrum fitting method is applied by using the Tauc’s model for estimating the optical band gap and the width of the band tail of the thin films. The optical band gap is calculated and is found to decrease with the Sn content.

Time-resolved Polarimetry of the Superluminous SN 2015bn with the Nordic Optical Telescope

DEFF Research Database (Denmark)

Leloudas, Giorgos; Maund, Justyn R.; Gal-Yam, Avishay

2017-01-01

We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs of spectropol......We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between -20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs...... of spectropolarimetry are also available. Based on field stars, we determine the interstellar polarization in the Galaxy to be negligible. The polarization of SN 2015bn shows a statistically significant increase during the last epochs, confirming previous findings. Our well-sampled imaging polarimetry series allows us...

Optical properties of α and β SnI2

International Nuclear Information System (INIS)

Kuku, T.A.

1985-10-01

Optical measurements have been taken in the spectral range 360 to 2,500 nm for thin films of red (α) and yellow (β) polymorphic forms SnI 2 . Excitonic transitions in both polymorphs are due to allowed indirect and nearby direct ones, with indirect excitation energies of 2.163, 2.275 eV and direct transition energies of 2.365 and 2.451 eV for the α and β polymorphs, respectively. The band gap energies and the calculated refractive index are related to the relative densities of the polymorphs. The optical transitions are interpreted to be due to the cations. (author)

Structural and optical characteristics of SnS thin film prepared by SILAR

Directory of Open Access Journals (Sweden)

Mukherjee A.

2015-12-01

Full Text Available SnS thin films were grown on glass substrates by a simple route named successive ion layer adsorption and reaction (SILAR method. The films were prepared using tin chloride as tin (Sn source and ammonium sulfide as sulphur (S source. The structural, optical and morphological study was done using XRD, FESEM, FT-IR and UV-Vis spectrophotometer. XRD measurement confirmed the presence of orthorhombic phase. Particle size estimated from XRD was about 45 nm which fitted well with the FESEM measurement. The value of band gap was about 1.63 eV indicating that SnS can be used as an important material for thin film solar cells. The surface morphology showed a smooth, homogenous film over the substrate. Characteristic stretching vibration mode of SnS was observed in the absorption band of FT-IR spectrum. The electrical activation energy was about 0.306 eV.

Studying Structural, Optical, Electrical, and Sensing Properties of Nanocrystalline SnO2:Cu Films Prepared by Sol-Gel Method for CO Gas Sensor Application at Low Temperature

Science.gov (United States)

Al-Jawad, Selma M. H.; Elttayf, Abdulhussain K.; Saber, Amel S.

Nanocrystalline SnO2 and SnO2:Cu thin films derived from SnCl2ṡ2H2O precursors have been prepared on glass substrates using sol-gel dip-coating technique. The deposited film was 300±20nm thick and the films were annealed in air at 500∘C for 1h. Structural, optical and sensing properties of the films were studied under different preparation conditions, such as Cu-doping concentration of 2%, 4% and 6wt.%. X-ray diffraction studies show the polycrystalline nature with tetragonal rutile structure of SnO2 and Cu:SnO2 thin films. The films have highly preferred orientation along (110). The crystallite size of the prepared samples reduced with increasing Cu-doping concentrations and the addition of Cu as dopants changed the structural properties of the thin films. Surface morphology was determined through scanning electron microscopy and atomic force microscopy. Results show that the particle size decreased as doping concentration increased. The films have moderate optical transmission (up to 82.4% at 800nm), and the transmittance, absorption coefficient and energy gap at different Cu-doping concentration were measured and calculated. Results show that Cu-doping decreased the transmittance and energy gap whereas it increased the absorption coefficient. Two peaks were noted with Cu-doping concentration of 0-6wt.%; the first peak was positioned exactly at 320nm ultraviolet emission and the second was positioned at 430-480nm. Moreover, emission bands were noticed in the photoluminescence spectra of Cu:SnO2. The electrical properties of SnO2 films include DC electrical conductivity, showing that the films have two activation energies, namely, Ea1 and Ea2, which increase as Cu-doping concentration increases. Cudoped nanocrystalline SnO2 gas-sensing material has better sensitivity to CO gas compared with pure SnO2.

Structural and optical properties of ZnO–SnO{sub 2} mixed thin films deposited by spray pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Tharsika, T., E-mail: tharsika@siswa.um.edu.my; Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Sabri, M.F.M., E-mail: faizul@um.edu.my

2014-05-02

Nanocrystalline ZnO–SnO{sub 2} mixed thin films were deposited by the spray pyrolysis technique at various substrate temperatures during deposition. The mixed films were prepared in the range of 20.9 at.% to 73.4 at.% by altering the Zn/(Sn + Zn) atomic ratio in the starting solution. Morphology, crystal structures, and optical properties of the films were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and ultraviolet–visible and photoluminescence (PL) spectroscopy. XRD analysis reveals that the crystallinity of the Sn-rich mixed thin films increases with increasing substrate temperatures. FESEM images show that the grain size of mixed thin films is smaller compared to that of pure ZnO and SnO{sub 2} thin films. A drop in the thickness and optical bandgap of the film was observed for films fabricated at high temperatures, which coincided with the increased crystallinity of the films. The average optical transmission of mixed thin films increased from 70% to 95% within the visible range (400–800 nm) as the substrate temperature increases. Optical bandgap of the films was determined to be in the range of 3.21–3.96 eV. The blue shift in the PL spectra from the films was supported by the fact that grain size of the mixed thin films is much smaller than that of the pure ZnO and SnO{sub 2} thin films. Due to the improved transmission and reduced grain size, the ZnO–SnO{sub 2} mixed thin films can have potential use in photovoltaic and gas sensing applications. - Highlights: • ZnO–SnO{sub 2} mixed thin films were deposited on glass substrate by spray pyrolysis. • Crystallinity of the thin films increases with substrate temperature. • Grain size of the mixed thin films is smaller than that of the pure thin films. • Reduction of grain size depends on mixed atomic ratios of precursor solution. • Optical band gap of films could be engineered by changing substrate temperature.

Study of structural, optical and thermal properties of nanostructured SnSe{sub 2} prepared by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Borges, Z.V. [Faculdade de Tecnologia, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Poffo, C.M., E-mail: claudio.poffo@ufsc.br [Universidade Federal de Santa Catarina, Campus de Araranguá, 88900-000, Santa Catarina (Brazil); Lima, J.C. de [Departamento de Física, Universidade Federal de Santa Catarina, Campus Trindade, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Souza, S.M. de; Trichês, D.M.; Nogueira, T.P.O. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Manzato, L. [Instituto Federal de Educação, Ciência e Tecnologia do Amazonas, 1672, 69075-351 Manaus, Amazonas (Brazil); Biasi, R.S. de [Seção de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro (Brazil)

2016-02-01

A nanostructured SnSe{sub 2} phase was successfully produced by mechanical alloying. The influence of defect centers on the structural, optical and photoacoustic properties of the alloy was investigated by annealing the as-milled SnSe{sub 2} powder. From optical absorbance and photoacoustic absorption measurements, the energy band gap, E{sub g}, and the thermal diffusivity, α, values were determined for as-milled and annealed samples. The thermal conductivity values for the as-milled and annealed samples were estimated by using the α values obtained from the photoacoustic measurements, the density values obtained from the Rietveld refinement of the X-ray diffraction patterns and the specific heat value for the bulk SnSe{sub 2} phase. These values were used to estimate the dimensionless figure of merit ZT. It was evidenced that the ZT parameter of the as-milled nanostructured SnSe{sub 2} sample is almost twice larger than the ZT of the annealed sample. - Highlights: • Nanostructured SnSe{sub 2} was produced using Mechanical Alloying technique. • As milled sample has a high fraction of interfacial component (80%). • Thermal diffusivity value for nanostructured SnSe{sub 2} was a new report in literature.

Electrical, optical and etching properties of Zn-Sn-O thin films deposited by combinatorial sputtering

International Nuclear Information System (INIS)

Kim, J. S.; Park, J. K.; Baik, Y. J.; Kim, W. M.; Jeong, J.; Seong, T. Y.

2012-01-01

Zn-Sn-O (ZTO) films are known to be able to form an amorphous phase, which provides a smooth surface morphology as well as etched side wall, when deposited by using the conventional sputtering technique and, therefore, to have a potential to be applied as transparent thin film transistors. In this study, ZTO thin films were prepared by using combined sputtering of ZnO and SnO 2 targets, and the dependences of their electrical and optical properties on the composition and the deposition parameters were examined. The Sn content in the films was varied in the range of 35 ∼ 85 at .%. The deposition was carried out at room temperature, 150 and 300 .deg. C, and the oxygen content in sputtering gas was varied from 0 to 1 vol.%. Sn-rich films had better electrical properties, but showed large oxygen deficiency when deposited at low oxygen partial pressures. ZTO films with Sn contents lower than 55 at.% had good optical transmission, but the electrical properties were poor due to very low carrier concentrations. A high Hall mobility of larger than 10 cm 2 /Vs could be obtained in the carrier density range 10 17 ∼ 10 20 cm -3 , and the etching rate was measurable for films with Sn content up to 70 at.% when using a dilute HCl solution, indicating a good possibility of utilizing ZTO films for device applications.

First-principles investigations on the mechanical, thermal, electronic, and optical properties of the defect perovskites Cs2Sn X 6 ( X = Cl, Br, I)

International Nuclear Information System (INIS)

Huang Hai-Ming; Jiang Zhen-Yi; Luo Shi-Jun

2017-01-01

The mechanical properties, thermal properties, electronic structures, and optical properties of the defect perovskites Cs 2 Sn X 6 ( X = Cl, Br, I) were investigated by first-principles calculation using PBE and HSE06 hybrid functional. The optic band gaps based on HSE06 are 3.83 eV for Cs 2 SnCl 6 , 2.36 eV for Cs 2 SnBr 6 , and 0.92 eV for Cs 2 SnI 6 , which agree with the experimental results. The Cs 2 SnCl 6 , Cs 2 SnBr 6 , and Cs 2 SnI 6 are mechanically stable and they are all anisotropic and ductile in nature. Electronic structures calculations show that the conduction band consists mainly of hybridization between the halogen p orbitals and Sn 5s orbitals, whereas the valence band is composed of the halogen p orbitals. Optic properties indicate that these three compounds exhibit good optical absorption in the ultraviolet region, and the absorption spectra red shift with the increase in the number of halogen atoms. The defect perovskites are good candidates for probing the lead-free and high power conversion efficiency of solar cells. (paper)

Optical and near-infrared observations of SN 2011dh - The first 100 days

Science.gov (United States)

Ergon, M.; Sollerman, J.; Fraser, M.; Pastorello, A.; Taubenberger, S.; Elias-Rosa, N.; Bersten, M.; Jerkstrand, A.; Benetti, S.; Botticella, M. T.; Fransson, C.; Harutyunyan, A.; Kotak, R.; Smartt, S.; Valenti, S.; Bufano, F.; Cappellaro, E.; Fiaschi, M.; Howell, A.; Kankare, E.; Magill, L.; Mattila, S.; Maund, J.; Naves, R.; Ochner, P.; Ruiz, J.; Smith, K.; Tomasella, L.; Turatto, M.

2014-02-01

We present optical and near-infrared (NIR) photometry and spectroscopy of the Type IIb supernova (SN) 2011dh for the first 100 days. We complement our extensive dataset with Swift ultra-violet (UV) and Spitzer mid-infrared (MIR) data to build a UV to MIR bolometric lightcurve using both photometric and spectroscopic data. Hydrodynamical modelling of the SN based on this bolometric lightcurve have been presented in Bersten et al. (2012, ApJ, 757, 31). We find that the absorption minimum for the hydrogen lines is never seen below ~11 000 km s-1 but approaches this value as the lines get weaker. This suggests that the interface between the helium core and hydrogen rich envelope is located near this velocity in agreement with the Bersten et al. (2012) He4R270 ejecta model. Spectral modelling of the hydrogen lines using this ejecta model supports the conclusion and we find a hydrogen mass of 0.01-0.04 M⊙ to be consistent with the observed spectral evolution. We estimate that the photosphere reaches the helium core at 5-7 days whereas the helium lines appear between ~10 and ~15 days, close to the photosphere and then move outward in velocity until ~40 days. This suggests that increasing non-thermal excitation due to decreasing optical depth for the γ-rays is driving the early evolution of these lines. The Spitzer 4.5 μm band shows a significant flux excess, which we attribute to CO fundamental band emission or a thermal dust echo although further work using late time data is needed. Thedistance and in particular the extinction, where we use spectral modelling to put further constraints, is discussed in some detail as well as the sensitivity of the hydrodynamical modelling to errors in these quantities. We also provide and discuss pre- and post-explosion observations of the SN site which shows a reduction by ~75 percent in flux at the position of the yellow supergiant coincident with SN 2011dh. The B, V and r band decline rates of 0.0073, 0.0090 and 0.0053 mag day-1

To study the linear and nonlinear optical properties of Se-Te-Bi-Sn/PVP (polyvinylpyrrolidone) nanocomposites

Science.gov (United States)

Tyagi, Chetna; Yadav, Preeti; Sharma, Ambika

2018-05-01

The present work reveals the optical study of Se82Te15Bi1.0Sn2.0/polyvinylpyrrolidone (PVP) nanocomposites. Bulk glasses of chalcogenide was prepared by well-known melt quenching technique. Wet chemical technique is proposed for making the composite of Se82Te15Bi1.0Sn2.0 and PVP polymer as it is easy to handle and cost effective. The composites films were made on glass slide from the solution of Se-Te-Bi-Sn and PVP polymer using spin coating technique. The transmission as well as absorbance is recorded by using UV-Vis-NIR spectrophotometer in the spectral range 350-700 nm. The linear refractive index (n) of polymer nanocomposites are calculated by Swanepoel approach. The linear refractive index (n) PVP doped Se82Te15Bi1.0Sn2.0 chalcogenide is found to be 1.7. The optical band gap has been evaluated by means of Tauc extrapolation method. Tichy and Ticha model was utilized for the characterization of nonlinear refractive index (n2).

Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

Science.gov (United States)

Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

2016-03-01

We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

Influence of Sn on the optical anisotropy of single-domain Si(001)

International Nuclear Information System (INIS)

Astropekakis, A.; Power, J.R.; Fleischer, K.; Esser, N.; Richter, W.; Galata, S.; Papadimitriou, D.

2001-01-01

We apply reflectance anisotropy spectroscopy (RAS) and low-energy electron diffraction (LEED) to the study of Sn deposited on a single-domain vicinal Si(001) sample. Large variations in RAS are recorded when up to 5 monolayers (ML) of Sn is deposited on the Si substrate at room temperature. We observe (2x2) and (1x1) LEED patterns for the 0.5-ML and 1.0-ML Sn covered surfaces, respectively. The (1x1) LEED pattern exists beyond this coverage and up to 5.0-ML deposition. Even though a (1x1) LEED pattern is observed upon deposition of 1.5 ML, surprisingly, a significant optical anisotropy is observed. After annealing to 570 degree sign C for 2 min, we observe a progression of LEED pattern changes from c(4x4)→(6x2)→c(8x4)→(5x1) with increased Sn coverage up to 1.5 ML. Similar RAS line shapes are obtained for all reconstructions produced through annealing with the exception of the (5x1). For the (5x1) phase, a significant anisotropy appears in the region of 1.8 eV. Similarities in the RAS line shape for both the (5x1) phase and that obtained after deposition of 1.5 ML of Sn at room temperature may indicate a RAS sensitivity to Sn dimer orientation within the uppermost layer

Comparison of the Distribution of Unsaturated Fatty Acids at the Sn-2 Position of Phospholipids and Triacylglycerols in Marine Fishes and Mammals.

Science.gov (United States)

Beppu, Fumiaki; Yasuda, Keiko; Okada, Ayako; Hirosaki, Yoshitsugu; Okazaki, Masako; Gotoh, Naohiro

2017-11-01

Highly unsaturated fatty acid (HUFA) binding at the sn-2 position of phospholipids (PL) becomes a resource for prostaglandin, leukotriene, resolvin, and protectin synthesis. Both triacylglycerol (TAG) and PL synthesis pathways in vivo are via phosphatidic acid; therefore, the distribution of fatty acid species at the sn-2 position must theoretically be the same for TAG and PL if rearrangement does not occur. However, it is known that little HUFA is located at the sn-2 position of TAG in marine mammals. Therefore, distribution of fatty acid species at the sn-2 position of TAG and PL was compared between marine fishes and mammals in this study. The composition of fatty acids binding at the sn-2 or sn-1,3 position of PL and TAG was analyzed via hydrolysis with enzymes and GC-FID. The results showed that 20:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3 were primarily located at the sn-1,3 positions of TAG in marine mammals. Comparison of the binding positions of HUFA and 16:0 in PL and TAG suggested the existence of Lands' cycle in marine fishes and mammals. In conclusion, both marine fishes and mammals condensed HUFA as a source of eicosanoid at the sn-2 position of PL. Furthermore, abundance ratios for 22:5n-3 or 22:6n-3 at the sn-2 position (sn-2 ratio) in TAG and PL (calculated by the equation: [abundance ratio at sn-2 position of TAG]/[abundance ratio at sn-2 position of PL]) was less than 0.35 in marine mammals; however, it was greater than 0.80 in marine fishes. These differences suggested that the HUFA consisted of 22 carbon atoms and had different roles in marine fishes and mammals.

Structural, electronic, optical and thermoelectric investigations of antiperovskites A3SnO (A = Ca, Sr, Ba) using density functional theory

Science.gov (United States)

Hassan, M.; Shahid, A.; Mahmood, Q.

2018-02-01

Density functional theory study of the structural, electrical, optical and thermoelectric behaviors of very less investigated anti-perovskites A3SnO (A = Ca, Sr, Ba) is performed with FP-LAPW technique. The A3SnO exhibit narrow direct band gap, in contrast to the wide indirect band gap of the respective perovskites. Hence, indirect to direct band gap transformation can be realized by the structural transition from perovskite to anti-perovskite. The p-p hybridization between A and O states result in the covalent bonding. The transparency and maximum reflectivity to the certain energies, and the verification of the Penn's model indicate potential optical device applications. Thermoelectric behaviors computed within 200-800 K depict that Ca3SnO exhibits good thermoelectric performance than Ba3SnO and Sr3SnO, and all three operate at their best at 800 K suggesting high temperature thermoelectric device applications.

Electrical and optical properties of nitrogen doped SnO2 thin films deposited on flexible substrates by magnetron sputtering

International Nuclear Information System (INIS)

Fang, Feng; Zhang, Yeyu; Wu, Xiaoqin; Shao, Qiyue; Xie, Zonghan

2015-01-01

Graphical abstract: The best SnO 2 :N TCO film: about 80% transmittance and 9.1 × 10 −4 Ω cm. - Highlights: • Nitrogen-doped tin oxide film was deposited on PET by RF-magnetron sputtering. • Effects of oxygen partial pressure on the properties of thin films were investigated. • For SnO 2 :N film, visible light transmittance was 80% and electrical resistivity was 9.1 × 10 −4 Ω cm. - Abstract: Nitrogen-doped tin oxide (SnO 2 :N) thin films were deposited on flexible polyethylene terephthalate (PET) substrates at room temperature by RF-magnetron sputtering. Effects of oxygen partial pressure (0–4%) on electrical and optical properties of thin films were investigated. Experimental results showed that SnO 2 :N films were amorphous state, and O/Sn ratios of SnO 2 :N films were deviated from the standard stoichiometry 2:1. Optical band gap of SnO 2 :N films increased from approximately 3.10 eV to 3.42 eV as oxygen partial pressure increased from 0% to 4%. For SnO 2 :N thin films deposited on PET, transmittance was about 80% in the visible light region. The best transparent conductive oxide (TCO) deposited on flexible PET substrates was SnO 2 :N thin films preparing at 2% oxygen partial pressure, the transmittance was about 80% and electrical conductivity was about 9.1 × 10 −4 Ω cm

Lattice positions of Sn in Cu2ZnSnS4 nanoparticles and thin films studied by synchrotron X-ray absorption near edge structure analysis

Science.gov (United States)

Zillner, E.; Paul, A.; Jutimoosik, J.; Chandarak, S.; Monnor, T.; Rujirawat, S.; Yimnirun, R.; Lin, X. Z.; Ennaoui, A.; Dittrich, Th.; Lux-Steiner, M.

2013-06-01

Lattice positions of Sn in kesterite Cu2ZnSnS4 and Cu2SnS3 nanoparticles and thin films were investigated by XANES (x-ray absorption near edge structure) analysis at the S K-edge. XANES spectra were analyzed by comparison with simulations taking into account anti-site defects and vacancies. Annealing of Cu2ZnSnS4 nanoparticle thin films led to a decrease of Sn at its native and defect sites. The results show that XANES analysis at the S K-edge is a sensitive tool for the investigation of defect sites, being critical in kesterite thin film solar cells.

Sub-2 nm SnO2 nanocrystals: A reduction/oxidation chemical reaction synthesis and optical properties

International Nuclear Information System (INIS)

Zhang Hui; Du Ning; Chen Bindi; Cui Tianfeng; Yang Deren

2008-01-01

A simple reduction/oxidation chemical solution approach at room temperature has been developed to synthesize ultrafine SnO 2 nanocrystals, in which NaBH 4 is used as a reducing agent instead of mineralizers such as sodium hydroxide, ammonia, and alcohol. The morphology, structure, and optical property of the ultrafine SnO 2 nanocrystals have been characterized by high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD), differential scanning calorimetry and thermogravimetric analysis (DSC-TGA), X-ray photoelectron spectroscopy (XPS) and UV-vis absorption spectroscopy. It is indicated that the uniform tetragonal ultrafine SnO 2 nanocrystals with the size below 2 nm have been fabricated at room temperature. The band gap of the ultrafine SnO 2 nanocrystals is about 4.1 eV, exhibiting 0.5 eV blue shift from that of the bulk SnO 2 (3.6 eV). Furthermore, the mechanism for the reduction/oxidation chemical reaction synthesis of the ultrafine SnO 2 nanocrystals has been preliminary presented

Electronic structure and optical properties of Sr{sub 2}SnO{sub 4} studied with FP-LAPW method in density functional theory

Energy Technology Data Exchange (ETDEWEB)

Prijamboedi, B., E-mail: boedi@chem.itb.ac.id; Umar, S.; Failamani, F. [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2015-04-16

Oxide material of Sr{sub 2}SnO{sub 4}, when it is doped with Ti becomes a phosphor material that can emit intense blue light at room temperature. It is important to study the electronic structure of this material in order to determine the optical processes that occur in Ti-doped Sr{sub 2}SnO{sub 4}. Electronic structure and optical properties of Sr{sub 2}SnO{sub 4} is studied using density functional theory framework with full potential linearized augmented plane waves plus local orbitals (FP-LAPW+lo) method. We use modified Becke-Johnson (mBJ) exchange-correlation potential to calculate the energy gap. Our calculation showed that Sr{sub 2}SnO{sub 4} has indirect band gap with band gap energy of around 4.2 eV. The experimental absorption spectra of Sr{sub 2}SnO{sub 4} indicated that this oxide has band gap of around 4.6 eV and it is closer to the results given by mBJ exchange-correlation potential. We also studied other optical properties of Sr{sub 2}SnO{sub 4} and it is found in agreement with the experimental results.

Modification of optical and electrical properties of chemical bath deposited SnS using O{sub 2} plasma treatments

Energy Technology Data Exchange (ETDEWEB)

Gómez, A. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Martínez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Calixto-Rodríguez, M. [Centro de Investigación en Energía, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Avellaneda, D. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, México (Mexico); Reyes, P.G. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Flores, O. [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico)

2013-06-15

In this paper, we report modifications of structural and optical, electrical properties that occur in tin sulphide (SnS) treated in O{sub 2} plasma. The SnS thin films were deposited by chemical bath deposition technique. The samples were treated in an O{sub 2} plasma discharge at 3 Torr of pressure discharge, a discharge voltage of 2.5 kV and 20 mA of discharge current. The prepared and treated thin films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The photoconductivity and electrical effects of SnS have been studied. The SnS thin films had an orthorhombic crystalline structure. With the plasma treatment the optical gap and electrical properties of the SnS films changed from 1.61 to 1.84 eV, for 3.9 × 10{sup 5} to 10.42 Ω cm, respectively. These changes can be attributed to an increase in electron density, percolation effects due to porosity, surface degradation/etching that is an increase in surface roughness, where some structural changes related to crystallinity occurs like a high grain size as revealed by SEM images.

Intercalation of organic molecules into SnS2 single crystals

International Nuclear Information System (INIS)

Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H.; Kloc, C.

2013-01-01

SnS 2 is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS 2e n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS 2 after intercalation revealed defects and stacking mismatches among the SnS 2 layers caused by the intercalation. UV–Vis absorption studies showed a red shift in the band edge of the SnS 2 material after intercalation. The band edge was 2.2 eV for pristine SnS 2 ; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS 2 single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS 2 after intercalation. Highlights: ► Organic molecules intercalated inhomogenously between covalently bonded SnS 2 layers. ► Ethylenediamine (en) intercalate directly into SnS 2 . ► Phenylenediamine (PPD) and naphthalenediamine (NDA) can be intercalated into SnS 2 secondary. ► In a secondary intercalation the bonds between layers are weakened by direct

Large lateral photovoltaic effect with ultrafast relaxation time in SnSe/Si junction

Energy Technology Data Exchange (ETDEWEB)

Wang, Xianjie; Zhao, Xiaofeng; Hu, Chang; Zhang, Yang; Song, Bingqian; Zhang, Lingli; Liu, Weilong; Lv, Zhe; Zhang, Yu; Sui, Yu, E-mail: suiyu@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Tang, Jinke [Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071 (United States); Song, Bo, E-mail: songbo@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150001 (China)

2016-07-11

In this paper, we report a large lateral photovoltaic effect (LPE) with ultrafast relaxation time in SnSe/p-Si junctions. The LPE shows a linear dependence on the position of the laser spot, and the position sensitivity is as high as 250 mV mm{sup −1}. The optical response time and the relaxation time of the LPE are about 100 ns and 2 μs, respectively. The current-voltage curve on the surface of the SnSe film indicates the formation of an inversion layer at the SnSe/p-Si interface. Our results clearly suggest that most of the excited-electrons diffuse laterally in the inversion layer at the SnSe/p-Si interface, which results in a large LPE with ultrafast relaxation time. The high positional sensitivity and ultrafast relaxation time of the LPE make the SnSe/p-Si junction a promising candidate for a wide range of optoelectronic applications.

Structural, optical, Induced ferromagnetism and anti-ferromagnetism in SnO2 nanoparticles by varying cobalt concentration

International Nuclear Information System (INIS)

Ali, Atif; Sarfraz, A.K.; Ali, Kashif; Mumtaz, A.

2015-01-01

The SnO 2 nanoparticles were prepared with different cobalt concentrations (0.0%, 0.5%, 1%, 3% and 4%) by chemical co-precipitation method. The NH 4 OH was used as precipitating agent; the pH value, reaction time and reaction temperature were optimized during synthesis. The x-ray diffraction (XRD) pattern reveals the formation of single phase tetragonal structure of undoped and cobalt doped SnO 2 nanoparticles which lies in the range of 19–22 nm calculated by De-Bye Scherrer's formula. The optical properties were studied by measuring the reflectance spectroscopy which shows that band gap energy decreases with increase in cobalt concentration. The magnetic characterization was performed by Quantum Design Physical property measurement system (PPMS). Interestingly magnetic measurements show that ferromagnetism in a Co doped SnO 2 becomes visible for x=0.5% and diminishes with further increasing of cobalt concentration. - Highlights: • SnO 2 nanoparticles were prepared with different cobalt concentrations (0.0 % 0.5%, 1%, 3% and 4%) by the chemical co-precipitation method. • Structure was confirmed through x-ray diffraction (XRD) analysis. • The optical properties were studied by measuring the reflectance spectroscopy. • The magnetic characterization was performed

Correlation between SnO{sub 2} nanocrystals and optical properties of Eu{sup 3+} ions in SiO{sub 2} matrix: Relation of crystallinity, composition, and photoluminescence

Energy Technology Data Exchange (ETDEWEB)

Thanh, Bui Quang [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hanoi (Viet Nam); Ha, Ngo Ngoc, E-mail: hann@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hanoi (Viet Nam); Khiem, Tran Ngoc, E-mail: khiem@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hanoi (Viet Nam); Chien, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hanoi (Viet Nam); School of Engineering Physics (SEP), Hanoi University of Science and Technology (HUST), No.1 Dai Co Viet, Hanoi (Viet Nam)

2015-07-15

We report characteristics and optical properties of Eu{sup 3+}-doped SnO{sub 2} nanocrystals dispersed in SiO{sub 2} matrix. Samples are prepared by the sol–gel method. Crystallinity of SnO{sub 2} nanocrystals is examined by X-ray diffraction experiments. At annealing temperatures from 900 to 1200 °C, we observe the formation of single tetragonal rutile structure of SnO{sub 2} nanocrystals. Average sizes of SnO{sub 2} nanocrystals within 3–7 nm are estimated by Debye–Scherrer equation. Intense photoluminescent spectra of Eu{sup 3+} ions consist of a series of resolved emission bands within 570–645 nm, which are varied with different sample-preparation conditions. We show the efficient excitation process of Eu{sup 3+} ions through SnO{sub 2} nanocrystals in the materials. Microscopic structure of SnO{sub 2} nanoparticles and optical properties of Eu{sup 3+} ions are also presented and discussed. - Highlights: • Thin layers of Eu{sup 3+} doped SnO{sub 2} nanocrystals dispersed in SiO{sub 2} were prepared by sol-gel method and spin-coating process. • Formation of single-phase tetragonal rutile structure of SnO{sub 2} nanocrystals and highly efficient optical excitation of the Eu{sup 3+} dopants were exhibited. • Relations of the crystallinity and composition of SnO{sub 2} and optical properties of Eu{sup 3+} dopants were comprehensively investigated and presented. • Allocations of major optically-active Eu{sup 3+} ions in the materials were deduced from their emission bands.

Role of Cu in engineering the optical properties of SnO2 nanostructures: Structural, morphological and spectroscopic studies

Science.gov (United States)

Kumar, Virender; Singh, Kulwinder; Jain, Megha; Manju; Kumar, Akshay; Sharma, Jeewan; Vij, Ankush; Thakur, Anup

2018-06-01

We have carried out a systematic study to investigate the effect of Cu doping on the optical properties of SnO2 nanostructures synthesized by chemical route. Synthesized nanostructures were characterized using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), High resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray spectroscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV-visible and Photoluminescence (PL) spectroscopy. The Rietveld refinement analysis of XRD patterns of Cu-doped SnO2 samples confirmed the formation of single phase tetragonal rutile structure, however some localized distortion was observed for 5 mol% Cu-doped SnO2. Crystallite size was found to decrease with increase in dopant concentration. FE-SEM images indicated change in morphology of samples with doping. HR-TEM images revealed that synthesized nanostructures were nearly spherical and average crystallite size was in the range 12-21 nm. Structural defects, crystallinity and size effects on doping were investigated by Raman spectroscopy and results were complemented by FTIR spectroscopy. Optical band gap of samples was estimated from reflectance spectra. We have shown that band gap of SnO2 can be engineered from 3.62 to 3.82 eV by Cu doping. PL emission intensity increased as the doping concentration increased, which can be attributed to the development of defect states in the forbidden transition region of band gap of SnO2 with doping. We have also proposed a band model owing to defect states in SnO2 to explain the observed PL in Cu doped SnO2 nanostructures.

Pressure effect on the structural, elastic, electronic and optical properties of the Zintl phase KAsSn, first principles study

Energy Technology Data Exchange (ETDEWEB)

Guechi, A., E-mail: ab_guechi@yahoo.fr [Institute of Optics and Precision Mechanics, Setif-1 University, 19000 Setif (Algeria); Laboratory of Optoelectronics and Components, Department of Physics, Faculty of Science, Setif-1 University, 19000 Setif (Algeria); Merabet, A. [Institute of Optics and Precision Mechanics, Setif-1 University, 19000 Setif (Algeria); Laboratory of Physics and Mechanics of Metallic Materials, Setif-1 University, 19000 Setif (Algeria); Chegaar, M. [Laboratory of Optoelectronics and Components, Department of Physics, Faculty of Science, Setif-1 University, 19000 Setif (Algeria); Bouhemadou, A. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, Setif-1 University, 19000 Setif (Algeria); Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Guechi, N. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, Setif-1 University, 19000 Setif (Algeria)

2015-02-25

Highlights: • KAsSn is interesting in the materials community due to its complex structure and narrow gap. • Physical properties of KAsSn have not taken much attention in previous studies. • The KAsSn structure is shown to be mechanically stable. • KAsSn is predicted to be brittleness and characterized by a weak elastic anisotropy. • Its high absorption in the U.V. energy range shows its use in the optoelectronic devices. - Abstract: In this work, a first-principles study of ternary Zintl phase KAsSn compound using density-functional theory (DFT) method within the generalized gradient approximation developed by Wu–Cohen (GGA-Wc) has been performed. Based on the optimized structural parameter, the electronic structure, elastic and optical properties have been investigated. The calculated lattice constants agree reasonably with the previous results. The effect of high pressure on the structural parameters has been shown. The elastic constants were calculated and satisfy the stability conditions for hexagonal crystal. These indicate that this compound is stable in the studied pressure regime. The single crystal elastic constants (C{sub ij}) and related properties are calculated using the static finite strain technique, moreover the polycrystalline elastic moduli such as bulk modulus, shear modulus, micro-hardness parameter H{sub ν}, Young’s modulus and Poisson’s ratio were estimated using Voigt, Reuss and Hill’s (VRH) approximations. The elastic anisotropy of the KAsSn was also analyzed. On another hand the Debye temperature was obtained from the average sound velocity. Electronic properties have been studied throughout the calculation of band structure, density of states and charge densities. It is shown that this crystal belongs to the semiconductors with a pseudo gap of about 0.34 eV. Furthermore, in order to clarify the optical transitions of this compound, linear optical functions including the complex dielectric function, refractive index

SN 2010jl: Optical to Hard X-ray Observations Reveal an Explosion Embedded In a Ten Solar Mass Cocoon

DEFF Research Database (Denmark)

Ofek, Eran O.; Zoglauer, Andreas; Boggs, Steven E.

2014-01-01

Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive to uncer......Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive...

Optical and infrared observations of SN 1987A from Cerro Tololo Inter-American Observatory

International Nuclear Information System (INIS)

Phillips, M.M.

1988-01-01

Results from optical and infrared observations of SN 1987A obtained at Cerro Tololo Inter-American Observatory over the first seven months since core collapse are reviewed. Around 130 days after outburst, the bolometric light curve began to smoothly decline at a rate of ∼ 0.01 mag day-1, providing dramatic confirmation of the prediction that radioactivity had powered the optical display after the first month./ the peculiar color changes are kinks observed beginning on the 25th day probably signaled the initial release of trapped energy from mass 56 material. The bolometric luminosity of SN 1987A was unusually low at first, but reached a value more typical of other type II supernovae by the time that the final exponential decline had begun. Over much of the period covered by these observations, the optical and infrared spectra were characterized by strong absorption lines of Ba II and Sr II. Comparison with the spectra of other type II supernovae at similar stages of evolution supports the suggestion that s-processed elements were enriched in the hydrogen envelope of the progenitor, Sanduleak - 69 degrees 202

Structural, elastic, electronic, bonding, and optical properties of BeAZ2 (A = Si, Ge, Sn; Z = P, As) chalcopyrites

International Nuclear Information System (INIS)

Fahad, Shah; Murtaza, G.; Ouahrani, T.; Khenata, R.; Yousaf, Masood; Omran, S.Bin; Mohammad, Saleh

2015-01-01

A first principles density functional theory (DFT) technique is used to study the structural, chemical bonding, electronic and optical properties of BeAZ 2 (A = Si, Ge, Sn; Z = P, As) chalcopyrite materials. The calculated parameters are in good agreement with the available experimental results. The lattice constants and the equilibrium volume increased as we moved from Si to Ge to Sn, whereas the c/a and internal parameters u decreased by shifting the cation from P to As. These compounds are elastically stable. An investigation of the band gap using the WC-GGA, EV-GGA, PBE-GGA and mBJ-metaGGA potentials suggested that BeSiP 2 and BeSiAs 2 are direct band gap compounds, whereas BeGeP 2, BeGeAs 2, BeSnP 2, BeSnAs 2 are indirect band gap compounds. The energy band gaps decreased by changing B from Si to Sn and increased by changing the anion C from P to As. The bonding among the cations and anions is primarily ionic. In the optical properties, the real and imaginary parts of the dielectric functions, reflectivity and optical conductivity have been studied over a wide energy range. - Highlights: • The compounds are studied by FP-LAPW method within mBJ approximation. • All of the studied materials show isotropic behaviour. • All the compounds show direct band gap nature. • Bonding nature is mostly covalent among the studied compounds. • High absorption peaks and reflectivity ensures there utility in optoelectronic devices

Effect of Sn doping on structural, mechanical, optical and electrical properties of ZnO nanoarrays prepared by sol-gel and hydrothermal process

Science.gov (United States)

Agarwal, Manish Baboo; Sharma, Akash; Malaidurai, M.; Thangavel, R.

2018-05-01

Undoped and Sn doped Zinc oxide nanorods were prepared by two step process: initially growth of seed layers by sol-gel spin coating technique and then zinc oxide nanorods by hydrothermal process using the precursors zinc nitrate hexahydrate, hexamine and tin chloride. The effects on the electrical, optical, mechanical and structural properties for various Sn concentrations were studied. The crystalline phase determination from X-ray diffraction (XRD) confirms that Sn doped ZnO nanorods have hexagonal wurtzite structure. The variations of stress and strain with different doping concentration of Sn in ZnO nanorods were studied. The doping effect on electrical properties and optical bandgap is estimated by current voltage characteristics and absorbance spectra respectively. The surface morphology was studied with field emission scanning electron microscope (FESEM), which shows that the formation of hexagonal nanorods arrays with increasing Sn concentration. The calculated value of Young's modulus of elasticity (Y) for all the samples remains same. These results can be used in optoelectronic devices.

Fabrication of textured SnO2 transparent conductive films using self-assembled Sn nanospheres

Science.gov (United States)

Fukumoto, Michitaka; Nakao, Shoichiro; Hirose, Yasushi; Hasegawa, Tetsuya

2018-06-01

We present a novel method to fabricate textured surfaces on transparent conductive SnO2 films by processing substrates through a bottom-up technique with potential for industrially scalable production. The substrate processing consists of three steps: deposition of precursor Sn films on glass substrates, formation of a self-assembled Sn nanosphere layer with reductive annealing, and conversion of Sn to SnO2 by oxidative annealing. Ta-doped SnO2 films conformally deposited on the self-assembled nanospherical SnO2 templates exhibited attractive optical and electrical properties, namely, enhanced haze values and low sheet resistances, for applications as transparent electrodes in photovoltaics.

Influence of film thickness on structural, optical, and electrical properties of spray deposited antimony doped SnO{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Yadav, Abhijit A., E-mail: aay_physics@yahoo.co.in

2015-09-30

Transparent conducting antimony doped SnO{sub 2} thin films with varying thickness were deposited by chemical spray pyrolysis technique from non-aqueous solvent Propan-2-ol. The effect of film thickness on the properties of antimony doped SnO{sub 2} thin films have been studied. X-ray diffraction measurements showed tetragonal crystal structure of as-deposited antimony doped SnO{sub 2} films irrespective of film thickness. The surface morphology of antimony doped SnO{sub 2} thin film is spherical with the continuous distribution of grains. Electrical and optical properties were investigated by Hall Effect and optical measurements. The average optical transmittance of films decreased from 89% to 73% within the visible range (350–850 nm) with increase in film thickness. The minimum value of sheet resistance observed is 4.81 Ω/cm{sup 2}. The lowest resistivity found is 3.76 × 10{sup −4} Ω cm at 660 nm film thickness. - Highlights: • Effect of film thickness on the properties of antimony doped SnO{sub 2} thin films • Crystalline size in the range of 34–37 nm • Average transmittance decreased from 89% to 73% in the visible region. • Minimum sheet resistance of 4.81 Ω/cm{sup 2} • Lowest resistivity is found to be 3.76 × 10{sup −4} Ω cm at 660 nm film thickness.

70 °C synthesis of high-Sn content (25%) GeSn on insulator by Sn-induced crystallization of amorphous Ge

Energy Technology Data Exchange (ETDEWEB)

Toko, K., E-mail: toko@bk.tsukuba.ac.jp; Oya, N.; Suemasu, T. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Saitoh, N.; Yoshizawa, N. [Electron Microscope Facility, TIA, AIST, 16-1 Onogawa, Tsukuba 305-8569 (Japan)

2015-02-23

Polycrystalline GeSn thin films are fabricated on insulating substrates at low temperatures by using Sn-induced crystallization of amorphous Ge (a-Ge). The Sn layer stacked on the a-Ge layer (100-nm thickness each) had two roles: lowering the crystallization temperature of a-Ge and composing GeSn. Slow annealing at an extremely low temperature of 70 °C allowed for a large-grained (350 nm) GeSn layer with a lattice constant of 0.590 nm, corresponding to a Sn composition exceeding 25%. The present investigation paves the way for advanced electronic optical devices integrated on a flexible plastic substrate as well as on a Si platform.

SN 2010jl: Optical to hard X-ray observations reveal an explosion embedded in a ten solar mass cocoon

International Nuclear Information System (INIS)

Ofek, Eran O.; Gal-Yam, Avishay; Arcavi, Iair; Zoglauer, Andreas; Boggs, Steven E.; Barriére, Nicolas M.; Reynolds, Stephen P.; Fryer, Chris L.; Even, Wesley; Harrison, Fiona A.; Kulkarni, Shrinivas R.; Bellm, Eric; Grefenstette, Brian; Cenko, S. Bradley; Bloom, Joshua S.; Filippenko, Alexei V.; Christensen, Finn; Craig, William W.; Hailey, Charles J.; Laher, Russ

2014-01-01

Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive to uncertainties regarding the CSM density profile and the ejecta velocity. Here we outline a method to measure the mass of the optically thick CSM around such SNe. We present new visible-light and X-ray observations of SN 2010jl (PTF 10aaxf), including the first detection of an SN in the hard X-ray band using NuSTAR. The total radiated luminosity of SN 2010jl is extreme—at least 9 × 10 50 erg. By modeling the visible-light data, we robustly show that the mass of the circumstellar material within ∼10 16 cm of the progenitor of SN 2010jl was in excess of 10 M ☉ . This mass was likely ejected tens of years prior to the SN explosion. Our modeling suggests that the shock velocity during shock breakout was ∼6000 km s –1 , decelerating to ∼2600 km s –1 about 2 yr after maximum light. Furthermore, our late-time NuSTAR and XMM spectra of the SN presumably provide the first direct measurement of SN shock velocity 2 yr after the SN maximum light—measured to be in the range of 2000-4500 km s –1 if the ions and electrons are in equilibrium, and ≳ 2000 km s –1 if they are not in equilibrium. This measurement is in agreement with the shock velocity predicted by our modeling of the visible-light data. Our observations also show that the average radial density distribution of the CSM roughly follows an r –2 law. A possible explanation for the ≳ 10 M ☉ of CSM and the wind-like profile is that they are the result of multiple pulsational pair instability events prior to the SN explosion, separated from each other by years.

Theoretical perspective on the electronic, magnetic and optical properties of Zn-doped monolayer SnS{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sun, Lili; Zhou, Wei; Liu, Yanyu; Yu, Dandan [Department of Applied Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Liang, Yinghua [College of Chemical Engineering, North China University of Science and Technology, Tangshan 063009 (China); Wu, Ping, E-mail: pingwu@tju.edu.cn [Department of Applied Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China)

2016-12-15

Highlights: • The Zn doping in monolayer SnS{sub 2} is energetically favored under S-rich condition. • The room temperature ferromagnetism can be realized in Zn-doped monolayer SnS{sub 2}. • The Zn doping enhances the effective utilization in the near-infrared light region. • The Zn doping could lead to the red shift of absorption edge in monolayer SnS{sub 2}. • The Zn-doped monolayer SnS{sub 2} is active for both the oxygen and hydrogen evolution. - Abstract: The electronic, magnetic and optical properties of Zn-doped monolayer SnS{sub 2} have been theoretically investigated with the density functional theory. Numerical results reveal that monolayer SnS{sub 2} can be easily synthesized by cleaving its bulk crystal. Besides, the Zn doping in monolayer SnS{sub 2} is energetically favored under the S-rich with respect to the Sn-rich condition. The doped system exhibits the magnetic ground states due to the formation of defect states above the Fermi level, which are introduced by the hybridization between S-3p states and a small amount of Sn-4d states. The room temperature ferromagnetism can also be realized in Zn-doped monolayer SnS{sub 2}. The injection of Zn can enhance the absorption efficiency of solar spectrum, especially in the near-infrared light region. Moreover, the Zn doping can enhance the photocatalytic activity for both the oxygen and hydrogen evolution reactions in the monolayer SnS{sub 2}.

Magnetic and optical properties of electrospun hollow nanofibers of SnO{sub 2} doped with Ce-ion

Energy Technology Data Exchange (ETDEWEB)

Mohanapriya, P.; Victor Jaya, N. [Department of Physics, Anna University, Chennai 600 025 (India); Pradeepkumar, R. [Centre for Nanoscience and Technology, Anna University, Chennai 600 025 (India); Natarajan, T. S., E-mail: tsn@physics.iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India)

2014-07-14

Cerium doped SnO{sub 2} hollow nanofibers were synthesized by electrospinning. High resolution scanning electron microscope (HRSEM) and transmission electron microscopy (TEM) analysis showed hollow nanofibers with diameters around ∼200 nm. The optimized substitution of Ce ion into SnO{sub 2} lattices happened above 6 mol. % doping as confirmed by Powder X-ray diffraction (XRD) studies. Optical band gap was decreased by the doping confirming the direct energy transfer between f-electrons of rare earth ion and the SnO{sub 2} conduction or valence band. The compound also exhibited room temperature ferromagnetism with the saturation magnetization of 19 × 10{sup −5} emu/g at 6 mol. %. This study demonstrates the Ce doped SnO{sub 2} hollow nanofibers for applications in magneto-optoelectronic devices.

Thin gold films on SnO2:In: Temperature-dependent effects on the optical properties

International Nuclear Information System (INIS)

Lansåker, P.C.; Niklasson, G.A.; Granqvist, C.G.

2012-01-01

Gold films with thicknesses of 5 ± 0.5 nm were sputter deposited onto SnO 2 :In-coated glass kept at different temperatures up to 140 °C, and similar films, deposited onto substrates at 25 °C, were annealing post treated at the same temperatures. Nanostructures and optical properties were recorded by scanning electron microscopy and spectrophotometry in the 0.3 to 2.5 μm wavelength range, respectively. Annealing had a minor influence on the optical transmittance despite significant changes in the scale of the nanostructure, whereas deposition onto substrates heated to 140 °C yielded granular films with strong plasmon absorption of luminous radiation. These results are of considerable interest for optical devices with gold films prepared at elevated temperature or operating at such temperature. - Highlights: ► Thin gold films have been deposited onto base layers of SnO 2 :In. ► The gold depositions were made onto both non-heated and heated substrates. ► Gold depositions onto non-heated substrates were followed by heat treatment. ► Depending on heating procedure, the gold films show apparently different structure.

Intercalation of organic molecules into SnS{sub 2} single crystals

Energy Technology Data Exchange (ETDEWEB)

Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore); Kloc, C., E-mail: ckloc@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore)

2013-02-15

SnS{sub 2} is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS{sub 2e}n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS{sub 2} after intercalation revealed defects and stacking mismatches among the SnS{sub 2} layers caused by the intercalation. UV-Vis absorption studies showed a red shift in the band edge of the SnS{sub 2} material after intercalation. The band edge was 2.2 eV for pristine SnS{sub 2}; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS{sub 2} single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS{sub 2} after intercalation. Highlights: Black-Right-Pointing-Pointer Organic molecules intercalated inhomogenously between covalently bonded SnS{sub 2} layers. Black-Right-Pointing-Pointer Ethylenediamine (en) intercalate directly into SnS{sub 2}. Black-Right-Pointing-Pointer Phenylenediamine (PPD) and naphthalenediamine (NDA) can be

OPTICAL OBSERVATIONS OF THE TYPE IA SUPERNOVA SN 2011fe IN M101 FOR NEARLY 500 DAYS

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kaicheng; Wang, Xiaofeng; Zhao, Xulin; Chen, Jia; Chen, Juncheng; Huang, Fang; Mo, Jun; Rui, Liming; Song, Hao; Sai, Hanna; Li, Wenxiong [Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing, 100084 (China); Zhang, JuJia; Bai, Jinming [Yunnan Astronomical Observatory of China, Chinese Academy of Sciences, Kunming, 650011 (China); Zhang, Tianmeng; Wu, Chao [National Astronomical Observatory of China, Chinese Academy of Sciences, Beijing, 100012 (China); Ganeshalingam, Mohan; Li, Weidong; Filippenko, Alexei V.; Zheng, Weikang [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Wang, Lifan, E-mail: wang_xf@mail.tsinghua.edu.cn [Physics and Astronomy Department, Texas A and M University, College Station, TX 77843 (United States)

2016-03-20

We present well-sampled optical observations of the bright Type Ia supernova (SN Ia) SN 2011fe in M101. Our data, starting from ∼16 days before maximum light and extending to ∼463 days after maximum, provide an unprecedented time series of spectra and photometry for a normal SN Ia. Fitting the early-time rising light curve, we find that the luminosity evolution of SN 2011fe follows a t{sup n} law, with the index n being close to 2.0 in the VRI bands but slightly larger in the U and B bands. Combining the published ultraviolet (UV) and near-infrared (NIR) photometry, we derive the contribution of UV/NIR emission relative to the optical. SN 2011fe is found to have stronger UV emission and reaches its UV peak a few days earlier than other SNe Ia with similar Δm{sub 15}(B), suggestive of less trapping of high-energy photons in the ejecta. Moreover, the U-band light curve shows a notably faster decline at late phases (t ≈ 100–300 days), which also suggests that the ejecta may be relatively transparent to UV photons. These results favor the notion that SN 2011fe might have a progenitor system with relatively lower metallicity. On the other hand, the early-phase spectra exhibit prominent high-velocity features (HVFs) of O i λ7773 and the Ca ii NIR triplet, but only barely detectable in Si ii 6355. This difference can be caused by either an ionization/temperature effect or an abundance enhancement scenario for the formation of HVFs; it suggests that the photospheric temperature of SN 2011fe is intrinsically low, perhaps owing to incomplete burning during the explosion of the white dwarf.

Structural, elastic, electronic, bonding, and optical properties of BeAZ{sub 2} (A = Si, Ge, Sn; Z = P, As) chalcopyrites

Energy Technology Data Exchange (ETDEWEB)

Fahad, Shah [Department of Physics, Hazara University Mansehra, KPK, Mansehra (Pakistan); Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Ouahrani, T. [Laboratoire de Physique Théorique, B.P. 230, Université de Tlemcen, Tlemcen 13000 (Algeria); Ecole Préparatoire en Sciences et Techniques, BP 165 R.P., 13000 Tlemcen (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Yousaf, Masood [Center for Multidimensional Carbon Materials, Institute for Basic Science, Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Omran, S.Bin [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Mohammad, Saleh [Department of Physics, Hazara University Mansehra, KPK, Mansehra (Pakistan)

2015-10-15

A first principles density functional theory (DFT) technique is used to study the structural, chemical bonding, electronic and optical properties of BeAZ{sub 2} (A = Si, Ge, Sn; Z = P, As) chalcopyrite materials. The calculated parameters are in good agreement with the available experimental results. The lattice constants and the equilibrium volume increased as we moved from Si to Ge to Sn, whereas the c/a and internal parameters u decreased by shifting the cation from P to As. These compounds are elastically stable. An investigation of the band gap using the WC-GGA, EV-GGA, PBE-GGA and mBJ-metaGGA potentials suggested that BeSiP{sub 2} and BeSiAs{sub 2} are direct band gap compounds, whereas BeGeP{sub 2,} BeGeAs{sub 2,} BeSnP{sub 2,} BeSnAs{sub 2} are indirect band gap compounds. The energy band gaps decreased by changing B from Si to Sn and increased by changing the anion C from P to As. The bonding among the cations and anions is primarily ionic. In the optical properties, the real and imaginary parts of the dielectric functions, reflectivity and optical conductivity have been studied over a wide energy range. - Highlights: • The compounds are studied by FP-LAPW method within mBJ approximation. • All of the studied materials show isotropic behaviour. • All the compounds show direct band gap nature. • Bonding nature is mostly covalent among the studied compounds. • High absorption peaks and reflectivity ensures there utility in optoelectronic devices.

Effect of Hydrostatic Pressure on the Structural, Electronic and Optical Properties of SnS2 with a Cubic Structure: The DFT Approach

Science.gov (United States)

Bakhshayeshi, A.; Taghavi Mendi, R.; Majidiyan Sarmazdeh, M.

2018-02-01

Recently, a cubic structure of polymorphic SnS2 has been synthesized experimentally, which is stable at room temperature. In this paper, we calculated some structural, electronic and optical properties of the cubic SnS2 structure based on the full potential-linearized augmented plane waves method. We also studied the effect of hydrostatic pressure on the physical properties of the cubic SnS2 structure. Structural results show that the compressibility of the cubic SnS2 phase is greater than its trigonal phase and the compressibility decreases with increasing pressure. Investigations of the electronic properties indicate that pressure changes the density of states and the energy band gap increases with increasing pressure. The variation of energy band gap versus pressure is almost linear. We concluded that cubic SnS2 is a semiconductor with an indirect energy band gap, like its trigonal phase. The optical calculations revealed that the dielectric constant decreases with increasing pressure, and the width of the forbidden energy interval increases for electromagnetic wave propagation. Moreover, plasmonic energy and refractive index are changed with increasing pressure.

Numerical study of the electronic structure, elastic and optical properties of defect quaternary semiconductor CuGaSnSe4

Science.gov (United States)

Shen, Kesheng; Lu, Hai; Zhang, Xianzhou; Jiao, Zhaoyong

2018-06-01

The electronic structure, elastic and optical properties of the defect quaternary semiconductor CuGaSnSe4 in I 4 bar structure are systematically investigated using first-principles calculations. We summarize and discuss some of the studies on CuGaSnSe4 in partially ordered chalcopyrite structure and find that there are three atomic arrangements so far, but it is still uncertain which is the most stable. Through detailed simulation and comparison with the corresponding literature, we get three models and predict that M1 model should be the most stable. The band structure and optical properties of compound CuGaSnSe4, including dielectric constant, refractive index and absorption spectrum, are drawn for a more intuitive understanding. The elastic constants are also calculated, which not only prove that CuGaSnSe4 in I 4 bar structure is stable naturally but also help solve the problem of no data to accurately predict axial thermal expansion coefficients. The calculated values of the zero frequency dielectric constant and refractive index are comparable to those of the corresponding chalcopyrite structure but slightly larger.

Time-resolved Polarimetry of the Superluminous SN 2015bn with the Nordic Optical Telescope

Energy Technology Data Exchange (ETDEWEB)

Leloudas, Giorgos; Gal-Yam, Avishay [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001 (Israel); Maund, Justyn R. [The Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Pursimo, Tapio [Nordic Optical Telescope, Apartado 474, E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Hsiao, Eric [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Malesani, Daniele; De Ugarte Postigo, Antonio [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Patat, Ferdinando [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Sollerman, Jesper [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Stritzinger, Maximilian D. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

2017-03-01

We present imaging polarimetry of the superluminous supernova SN 2015bn, obtained over nine epochs between −20 and +46 days with the Nordic Optical Telescope. This was a nearby, slowly evolving Type I superluminous supernova that has been studied extensively and for which two epochs of spectropolarimetry are also available. Based on field stars, we determine the interstellar polarization in the Galaxy to be negligible. The polarization of SN 2015bn shows a statistically significant increase during the last epochs, confirming previous findings. Our well-sampled imaging polarimetry series allows us to determine that this increase (from ∼0.54% to ≳1.10%) coincides in time with rapid changes that took place in the optical spectrum. We conclude that the supernova underwent a “phase transition” at around +20 days, when the photospheric emission shifted from an outer layer, dominated by natal C and O, to a more aspherical inner core, dominated by freshly nucleosynthesized material. This two-layered model might account for the characteristic appearance and properties of Type I superluminous supernovae.

Electrochemical and optical properties of CeO2-SnO2 and CeO2-SnO2:X (X = Li, C, Si films

Directory of Open Access Journals (Sweden)

Berton Marcos A.C.

2001-01-01

Full Text Available Thin solid films of CeO2-SnO2 (17 mol% Sn and CeO2-SnO2:X (X = Li, C and Si were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air. The electrochemical and optical properties of the films were determined from the cyclic voltammetry and chronoamperometry measurements using 0.1 M LiOH as supporting electrolyte. The ion storage capacity of the films was investigated using in situ spectroelectrochemical method and during the insertion/extraction process the films remained transparent. The powders were characterized by thermal analysis (DSC/TGA and X-ray diffraction.

Effect of Sn-doped on microstructural and optical properties of ZnO thin films deposited by sol-gel method

International Nuclear Information System (INIS)

Tsay, C.-Y.; Cheng, H.-C.; Tung, Y.-T.; Tuan, W.-H.; Lin, C.-K.

2008-01-01

In this study, transparent thin films of Sn-doped ZnO (ZnO:Sn) were deposited onto alkali-free glass substrates by a sol-gel method; the effect of Sn doping on crystallinity, microstructural and optical properties was investigated. The atomic percentages of dopant in ZnO-based sols were Sn/Zn = 0, 1, 2, 3, and 5 at.%. The as-deposited films were pre-heated at 300 deg. C for 10 min and then annealed in air at 500 deg. C for 1 h. The results show that Sn-doped ZnO thin films demonstrate obviously improved surface roughness, enhanced transmittance in the 400-600 nm wavelength range and reduced average crystallite size. Among all of the annealed ZnO-based films in this study, films doped with 2 at.% Sn concentration exhibited the best properties, namely an average transmittance of 90%, an RMS roughness value of 1.92 nm and a resistivity of 9.3 x 10 2 Ω-cm

Tuning direct bandgap GeSn/Ge quantum dots' interband and intraband useful emission wavelength: Towards CMOS compatible infrared optical devices

Science.gov (United States)

Baira, Mourad; Salem, Bassem; Madhar, Niyaz Ahamad; Ilahi, Bouraoui

2018-05-01

In this work, interband and intraband optical transitions from direct bandgap strained GeSn/Ge quantum dots are numerically tuned by evaluating the confined energies for heavy holes and electrons in D- and L-valley. The practically exploitable emission wavelength ranges for efficient use in light emission and sensing should fulfill specific criteria imposing the electrons confined states in D-valley to be sufficiently below those in L-valley. This study shows that GeSn quantum dots offer promising opportunity towards high efficient group IV based infrared optical devices operating in the mid-IR and far-IR wavelength regions.

MeV ion irradiation induced evolution of morphological, structural and optical properties of nanostructured SnO2 thin films

International Nuclear Information System (INIS)

Mohapatra, Satyabrata; Bhardwaj, Neha; Pandey, Akhilesh

2015-01-01

Nanostructured SnO 2 thin films were prepared by carbothermal evaporation method. Morphological, structural and optical properties of the SnO 2 thin films, before and after 8 MeV Si ion irradiation to fluences varying from 1 × 10 13 to 1 × 10 15 ions cm −2 , were well characterized using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), Raman spectroscopy and photoluminescence spectroscopy (PL). XRD studies revealed the presence of SnO 2 and Sn nanoparticles in the as-deposited samples. AFM and FESEM studies on the irradiated samples revealed formation of nanoring-like structures, at a fluence of 1 × 10 15 ions cm −2 , with a central hole and circular rim consisting of nearly monodisperse SnO 2 nanoparticles. PL studies revealed strong enhancement in UV emissions upon 8 MeV Si ion irradiation. A growth mechanism underlying the formation of SnO 2 nanorings involving self-assembly of SnO 2 nanoparticles around nanoholes is tentatively proposed. (paper)

Spectroscopic ellipsometry characterization of ZnO:Sn thin films with various Sn composition deposited by remote-plasma reactive sputtering

Science.gov (United States)

Janicek, Petr; Niang, Kham M.; Mistrik, Jan; Palka, Karel; Flewitt, Andrew J.

2017-11-01

ZnO:Sn thin films were deposited onto thermally oxidized silicon substrates using a remote plasma reactive sputtering. Their optical constants (refractive index n and extinction coefficient k) were determined from ellipsometric data recorded over a wide spectral range (0.05-6 eV). Parametrization of ZnO:Sn complex dielectric permittivity consists of a parameterized semiconductor oscillator function describing the short wavelength absorption edge, a Drude oscillator describing free carrier absorption in near-infrared part of spectra and a Lorentz oscillator describing the long wavelength absorption edge and intra-band absorption in the ultra-violet part of the spectra. Using a Mott-Davis model, the increase in local disorder with increasing Sn doping is quantified from the short wavelength absorption edge onset. Using the Wemple-DiDomenico single oscillator model for the transparent part of the optical constants spectra, an increase in the centroid distance of the valence and conduction bands with increasing Sn doping is shown and only slight increase in intensity of the inter-band optical transition due to Sn doping occurs. The Drude model applied in the near-infrared part of the spectra revealed the free carrier concentration and mobility of ZnO:Sn. Results show that the range of transparency of prepared ZnO:Sn layers is not dramatically affected by Sn doping whereas electrical conductivity could be controlled by Sn doping. Refractive index in the transparent part is comparable with amorphous Indium Gallium Zinc Oxide allowing utilization of prepared ZnO:Sn layers as an indium-free alternative.

Effect of annealing on structural and optical properties of Cu_2ZnSnS_4 thin films grown by pulsed laser deposition

International Nuclear Information System (INIS)

Surgina, G.D.; Nevolin, V.N.; Sipaylo, I.P.; Teterin, P.E.; Medvedeva, S.S.; Lebedinsky, Yu.Yu.; Zenkevich, A.V.

2015-01-01

In this work, we compare the effect of different types of thermal annealing on the morphological, structural and optical properties of Cu_2ZnSnS_4 (CZTS) thin films grown by reactive Pulsed Laser Deposition in H_2S flow. Rutherford backscattering spectrometry, atomic force microscopy, X-ray diffraction, Raman spectroscopy and optical spectrophotometry data reveal dramatic increase of the band gap and the crystallite size without the formation of secondary phases upon annealing in N_2 at the optimized conditions. - Highlights: • Cu_2ZnSnS_4 (CZTS) thin films were grown at room temperature. • Reactive Pulsed Laser Deposition in H_2S flow was used as a growth method. • Effect of annealing conditions on CZTS structural and optical properties is revealed. • Both the grain size and the band gap of CZTS film increase following the annealing. • Annealing in N_2 effectively inhibits the formation of Sn_xS secondary phases.

Synthesis of sub-5 nm Co-doped SnO{sub 2} nanoparticles and their structural, microstructural, optical and photocatalytic properties

Energy Technology Data Exchange (ETDEWEB)

Entradas, T.; Cabrita, J.F. [Department of Chemistry and Biochemistry and CQB, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Dalui, S. [Department of Physics and ICEMS, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Nunes, M.R. [Department of Chemistry and Biochemistry and CQB, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Monteiro, O.C., E-mail: ocmonteiro@fc.ul.pt [Department of Chemistry and Biochemistry and CQB, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisboa (Portugal); Silvestre, A.J., E-mail: asilvestre@deq.isel.ipl.pt [Department of Physics and ICEMS, Instituto Superior de Engenharia de Lisboa – ISEL, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa (Portugal)

2014-10-15

A swift chemical route to synthesize Co-doped SnO{sub 2} nanopowders is described. Pure and highly stable Sn{sub 1−x}Co{sub x}O{sub 2−δ} (0 ≤ x ≤ 0.15) crystalline nanoparticles were synthesized, with mean grain sizes <5 nm and the dopant element homogeneously distributed in the SnO{sub 2} matrix. The UV–visible diffuse reflectance spectra of the Sn{sub 1−x}Co{sub x}O{sub 2−δ} samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The samples' Urbach energies were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn{sub 1−x}Co{sub x}O{sub 2−δ} samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn{sub 0.95}Co{sub 0.05}O{sub 2−δ} nanoparticles in 60 min of irradiation. - Highlights: • Synthesis of homogeneous sub-5 nm Sn{sub 1−x}Co{sub x}O{sub 2−δ} (0 ≤ x ≤ 0.15) nanoparticles. • Samples' optical bandgap energies decrease with increasing Co concentration. • Samples' Urbach energies are calculated and correlated with their bandgap energies. • Sn{sub 1−x}Co{sub x}O{sub 2−δ} powders are photocatalysts for 4-hydroxylbenzoic acid degradation. • The best 4-HBA photocatalyst is the sample with composition Sn{sub 0.95}Co{sub 0.05}O{sub 2−δ}.

Electrical and optical properties of thin films with a SnS{sub 2} - Bi{sub 2}S{sub 3} alloy grown by sulphurization

Energy Technology Data Exchange (ETDEWEB)

Dussan, A; Mesa, F; Gordillo, G [Departamento de Fisica, Universidad Nacional de Colombia, Bogota Cr.30 No 45-03 (Colombia); Botero, M, E-mail: ggordillog@unal.edu.c, E-mail: adussanc@unal.edu.c [Departamento de Fisica, Universidad Central, Bogota Cr.5 No 21A-03 (Colombia)

2009-05-01

In this work, thin films of SnS{sub 2} with increased Bi content were grown by sulphurization of a thin film of Sn:Bi alloy, at temperatures around 300{sup 0}C. The effect of the Bi concentration on the optical, electrical and structural properties was determined through measurements of spectral transmittance, conductivity and x-ray diffraction XRD respectively. It was found that the optical constants (refractive index n, absorption coefficient alpha and energy gap Eg) and the electrical conductivity are significantly affected by the Bi concentration. In particular, a variation of the energy gap between 1.44 and 1.63 eV and a change of the conductivity greater than three orders of magnitude were observed when the content of Bi in the Sn:Bi alloy varied between 0 and 100 %. The analysis of the XRD measurements allowed us to find that the SnS: Bi films grow with a mixture of the SnS{sub 2} and Bi{sub 2}S{sub 3} phases, independently of the Bi content.

Determination of fundamental optical constants of Zn2SnO4 films

Directory of Open Access Journals (Sweden)

A.O. Salohub

2017-04-01

Full Text Available Examined in this paper have been optical properties of polycrystalline films Zn2SnO4 deposited using the spray pyrolysis method within the range of substrate temperatures 250 °C to 450 °C in increments of 50 °C. The spectral dependences have been found for the following physical quantities: k(, n(, ε1(, ε2( and defined as they change under the influence of substrate temperature Тs. Moreover, using the model by Wemple–DiDomenico it was calculated the dispersion energy Ео and Ed for this oxide. Two independent methods defined band gaps Zn2SnO4, which decreases from 4.21…4.22 eV down to 4.04…4.05 eV with increasing Тs from 250 °C up to 450 °C.

Properties of SN1978K from multi-wavelength observations

Science.gov (United States)

Schlegel, Eric M.; Ryder, Stuart; Staveley-Smith, L.; Colbert, E.; Petre, R.; Dopita, M.; Campbell-Wilson, D.

2000-06-01

We update the light curves from the X-ray, optical, and radio bandpasses which we have assembled over the past decade, and present two observations in the ultraviolet using the Hubble Space Telescope Faint Object Spectrograph. The HRI X-ray light curve is constant within the errors over the entire observation period which is confirmed by ASCA GIS data obtained in 1993 and 1995. In the UV, we detected the Mg II doublet at 2800 Å and a line at ~3190 Å attributed to He I 3187 at SN1978K's position. The optical light curve is formally constant within the errors, although a slight upward trend may be present. The radio light curve continues its steep decline. The longer time span of our radio observations compared to previous studies shows that SN1978K belongs in the class of highly X-ray and radio-luminous supernovae. The Mg II doublet flux ratio implies the quantity of line optical depth times density is ~1014 cm-3. The emission site must lie in the shocked gas. .

Position coincidence optical identifications using Texas interferometer radio positions

International Nuclear Information System (INIS)

Bozyan, E.P.

1979-01-01

1048 radio source positions measured with the Texas Interferometer were searched for optical identifications on glass copies of the Palomar Sky Survey E and O plates, resulting in 242 identifications and 806 blank fields. Finding charts are presented for 124 of the 125 new identifications not previously reported in the literature, and for 73 blank fields containing nearby optical objects which may be real identifications. This brings the cumulative number of Texas radio positions searched to 2015, producing 864 optical identifications and 1151 blank fields

XRF 100316D/SN 2010bh and the nature of gamma-ray burst supernovae

NARCIS (Netherlands)

Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Levan, A.J.; Tanvir, N.R.; Wiersema, K.; D'Avanzo, P.; Fruchter, A.S.; Garnavich, P.; Gomboc, A.; Gorosabel, J.; Kasen, D.; Kopač, D.; Margutti, R.; Mazzali, P.A.; Melandri, A.; Mundell, C.G.; Nugent, P.E.; Pian, E.; Smith, R.J.; Steele, I.; Wijers, R.A.M.J.; Woosley, S.E.

2011-01-01

We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN

RED AND DEAD: THE PROGENITOR OF SN 2012aw IN M95

International Nuclear Information System (INIS)

Fraser, M.; Maund, J. R.; Smartt, S. J.; Inserra, C.; Kotak, R.; Reilly, E.; Botticella, M.-T.; Dall'Ora, M.; Tomasella, L.; Benetti, S.; Ciroi, S.; Ochner, P.; Pastorello, A.; Valenti, S.; Eldridge, J. J.; Ergon, M.; Sollerman, J.; Taddia, F.; Mattila, S.; Stephens, A.

2012-01-01

Core-collapse supernovae (SNe) are the spectacular finale to massive stellar evolution. In this Letter, we identify a progenitor for the nearby core-collapse SN 2012aw in both ground-based near-infrared and space-based optical pre-explosion imaging. The SN itself appears to be a normal Type II Plateau event, reaching a bolometric luminosity of 10 42 erg s –1 and photospheric velocities of ∼11,000 km s –1 from the position of the Hβ P-Cygni minimum in the early SN spectra. We use an adaptive optics image to show that the SN is coincident to within 27 mas with a faint, red source in pre-explosion HST+WFPC2, VLT+ISAAC, and NTT+SOFI images. The source has magnitudes F555W = 26.70 ± 0.06, F814W = 23.39 ± 0.02, J = 21.1 ± 0.2, K = 19.1 ± 0.4, which, when compared to a grid of stellar models, best matches a red supergiant. Interestingly, the spectral energy distribution of the progenitor also implies an extinction of A V > 1.2 mag, whereas the SN itself does not appear to be significantly extinguished. We interpret this as evidence for the destruction of dust in the SN explosion. The progenitor candidate has a luminosity between 5.0 and 5.6 log L/L ☉ , corresponding to a zero-age main-sequence mass between 14 and 26 M ☉ (depending on A V ), which would make this one of the most massive progenitors found for a core-collapse SN to date.

Microstructural, optical and electrical transport properties of Cd-doped SnO2 nanoparticles

Science.gov (United States)

Ahmad, Naseem; Khan, Shakeel; Mohsin Nizam Ansari, Mohd

2018-03-01

We have successfully investigated the structural, optical and dielectric properties of Cd assimilated SnO2 nanoparticles synthesized via very convenient precipitation route. The structural properties were studied by x-ray diffraction method (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. As-synthesized samples in the form of powder were examined for its morphology and average particle size by Transmission electron microscopy (TEM). The optical properties were studied by diffuse reflectance spectroscopy. Dielectric properties such that complex dielectric constant and ac conductivity were investigated by LCR meter. Average crystallite size calculated by XRD and average particle size obtained from TEM were found to be consistent and below 50 nm for all samples. The optical band gap of as-synthesized powder samples from absorption study was found in the range of 3.76 to 3.97 eV. The grain boundary parameters such that Rgb, Cgb and τ were evaluated using impedance spectroscopy.

SN 2014J at M82 - I. A middle-class Type Ia supernova by all spectroscopic metrics

Science.gov (United States)

Galbany, L.; Moreno-Raya, M. E.; Ruiz-Lapuente, P.; González Hernández, J. I.; Méndez, J.; Vallely, P.; Baron, E.; Domínguez, I.; Hamuy, M.; López-Sánchez, A. R.; Mollá, M.; Catalán, S.; Cooke, E. A.; Fariña, C.; Génova-Santos, R.; Karjalainen, R.; Lietzen, H.; McCormac, J.; Riddick, F. C.; Rubiño-Martín, J. A.; Skillen, I.; Tudor, V.; Vaduvescu, O.

2016-03-01

We present the intensive spectroscopic follow up of the Type Ia supernova (SN Ia) 2014J in the starburst galaxy M82. Twenty-seven optical spectra have been acquired from 2014 January 22 to September 1 with the Isaac Newton and William Herschel Telescopes. After correcting the observations for the recession velocity of M82 and for Milky Way and host galaxy extinction, we measured expansion velocities from spectral line blueshifts and pseudo-equivalent width of the strongest features in the spectra, which gives an idea on how elements are distributed within the ejecta. We position SN 2014J in the Benetti, Branch et al. and Wang et al. diagrams. These diagrams are based on properties of the Si II features and provide dynamical and chemical information about the SN ejecta. The nearby SN 2011fe, which showed little evidence for reddening in its host galaxy, is shown as a reference for comparisons. SN 2014J is a border-line object between the Core-normal and Broad-line groups, which corresponds to an intermediate position between low-velocity gradient and high-velocity gradient objects. SN 2014J follows the R(Si II)-Δm15 correlation, which confirms its classification as a relatively normal SN Ia. Our description of the SN Ia in terms of the evolution of the pseudo-equivalent width of various ions as well as the position in the various diagrams put this specific SN Ia into the overall sample of SN Ia.

Effect of annealing on structural and optical properties of Cu{sub 2}ZnSnS{sub 4} thin films grown by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Surgina, G.D., E-mail: silvereye@bk.ru [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation); Nevolin, V.N. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Sipaylo, I.P.; Teterin, P.E. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Medvedeva, S.S. [Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation); Lebedinsky, Yu.Yu.; Zenkevich, A.V. [National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow 115409 (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region 141700 (Russian Federation)

2015-11-02

In this work, we compare the effect of different types of thermal annealing on the morphological, structural and optical properties of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films grown by reactive Pulsed Laser Deposition in H{sub 2}S flow. Rutherford backscattering spectrometry, atomic force microscopy, X-ray diffraction, Raman spectroscopy and optical spectrophotometry data reveal dramatic increase of the band gap and the crystallite size without the formation of secondary phases upon annealing in N{sub 2} at the optimized conditions. - Highlights: • Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were grown at room temperature. • Reactive Pulsed Laser Deposition in H{sub 2}S flow was used as a growth method. • Effect of annealing conditions on CZTS structural and optical properties is revealed. • Both the grain size and the band gap of CZTS film increase following the annealing. • Annealing in N{sub 2} effectively inhibits the formation of Sn{sub x}S secondary phases.

Effect of Pd ion doping in the band gap of SnO{sub 2} nanoparticles: structural and optical studies

Energy Technology Data Exchange (ETDEWEB)

Nandan, Brajesh; Venugopal, B. [Pondicherry University, Centre for Nanoscience and Technology (India); Amirthapandian, S.; Panigrahi, B. K. [Indira Gandhi Centre for Atomic Research, Ion Beam and Computer Simulation Section, Materials Science Group (India); Thangadurai, P., E-mail: thangadurai.p@gmail.com [Pondicherry University, Centre for Nanoscience and Technology (India)

2013-10-15

Pd ion doping has influenced the band gap of SnO{sub 2} nanoparticles. Undoped and Pd ion-doped SnO{sub 2} nanoparticles were synthesized by chemical co-precipitation method. A tetragonal phase of SnO{sub 2} with a grain size range of 7-13 nm was obtained (studied by X-ray diffraction and transmission electron microscopy). A decreasing trend in the particle size with increasing doping concentration was observed. The presence of Pd in doped SnO{sub 2} was confirmed by chemical analysis carried out by energy-dispersive spectroscopy in the transmission electron microscope. Diffuse reflectance spectra showed a blue shift in absorption with increasing palladium concentration. Band gap of SnO{sub 2} nanoparticles was estimated from the diffuse reflectance spectra using Kubelka-Munk function and it was increasing with the increase of Pd ion concentration from 3.73 to 4.21 eV. The variation in band gap is attributed predominantly to the lattice strain and particle size. All the samples showed a broad photoluminescence emission centered at 375 nm when excited at 270 nm. A systematic study on the structural and optical properties of SnO{sub 2} nanoparticles is presented.

Modification of the morphology and optical properties of SnS films using glancing angle deposition technique

Energy Technology Data Exchange (ETDEWEB)

Sazideh, M.R., E-mail: Mohammadrezasazideh@gmail.com [Thin Film Lab., Faculty of Physics, Semnan University, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Dizaji, H. Rezagholipour, E-mail: hrgholipour@semnan.ac.ir [Faculty of Physics, Semnan University, P.O. Box: 35195-363, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Ehsani, M.H., E-mail: mhe_ehsani@yahoo.com [Faculty of Physics, Semnan University, P.O. Box: 35195-363, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Moghadam, R. Zarei, E-mail: r.zarei1991@gmail.com [Thin Film Lab., Faculty of Physics, Semnan University, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of)

2017-05-31

Highlights: • SnS thin films produced by thermal evaporation method using glancing angle deposition technique. • At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range. • FESEM images showed drastic changes in the structure and morphology of individual nano-plates as a function of incident angle deposition. - Abstract: Tin sulfide (SnS) films were prepared by thermal evaporation method using Glancing Angle Deposition (GLAD) technique at zero and different oblique incident flux angles (α = 45°, 55°, 65°, 75° and 85°). The physical properties of prepared films were systematically investigated. The X-ray diffraction analysis indicated that the film deposited at α = 0° formed as single phase with an orthorhombic structure. However, the layers became amorphous at α = 45°, 55°, 65°, 75° and 85°. Beside the appearance of amorphous feature in the film prepared at α higher than zero, Sn{sub 2}S{sub 3} phase was also observed. The top and cross-sectional field emission scanning electron microscope (FESEM) images of the samples showed noticeable changes in the structure and morphology of individual nano-plates as a function of incident angle. The band gap and refractive index values of the films were calculated by optical transmission measurements. The optical band-gap values were observed to increase with increasing the incident flux angle. This can be due to presence of Sn{sub 2}S{sub 3} phase observed in the samples produced at α values other than zero. The effective refractive index and porosity exhibit an opposite evolution as the incident angle α rises. At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range.

Photoinduced non-linear optical effects in the ZnS-Al, In-Sn doped film-glass nanometer-sized interfaces

International Nuclear Information System (INIS)

Kityk, I.V.; Makowska-Janusik, M.; Ebothe, J.; El Hichou, A.; El Idrissi, B.; Addou, M.

2002-01-01

The effective nanometer-sized thin layer (about 1-2 nm) located between a crystalline ZnS film and glass substrate is studied here using photoinduced optical and second-order non-linear optical (second harmonic generation (SHG) and electrooptics effects) techniques. A photoinduced shift of the effective energy gap is found for the first time in ZnS films doped with the same amount (4 at.%) of different elements, namely, In, Al and Sn. The photoinduced second-order non-linear optical properties (linear electrooptics (LEO) and SHG) of the specimens show a good correlation with the corresponding features of the linear optical susceptibilities, particularly, the imaginary part of dielectric susceptibility near the absorption edge. The maximal response of the photoinduced signal is observed for the pump-probe delaying time of about 20 ps. The performed experimental measurements indicate that the observed effects are stimulated by two factors: the first one is connected with the interface potential gradients at the glass-ZnS film boarder; the second one is a consequence of the additional polarization due to the insertion of Al, In and Sn atoms. The observed phenomenon may be proposed as a sensitive tool for investigation of thin semiconducting-glass interface layer. Moreover, such nanolayers may be applied in quantum electronic devices

Dosimetric sensing and optical properties of ZnO–SnO2 nanocomposites synthesized by co-precipitation method

International Nuclear Information System (INIS)

Baitha, Pankaj Kr.; Pal, Partha P.; Manam, J.

2014-01-01

In this study an effort has been made to investigate the dosimetric sensing and optical properties of ZnO–SnO 2 nanocomposites at different pH values. The nanocomposites samples are irradiated by X-ray and then thermoluminescence (TL) analysis is carried out to investigate the response. The structural details of nanocomposites are characterized by Scanning Electron microscope, X-Ray Powder Diffraction and Fourier Transform Infrared Spectroscopy. Similarly, optical properties were characterized by UV–vis spectroscopy and Photoluminescence spectroscopy. The XRD studies revealed good crystallnity of samples with presence of both phases, ZnO as well as SnO 2 simultaneously. The SEM image revealed nanoflakes and nanoflower shape of ZnO–SnO 2 nanocomposite for sample synthesized at pH 7. Also, nanocube and nanosphere can be seen at higher pH value of 9. The room temperature photoluminescence spectra of ZnO–SnO 2 nanocomposite contain multi peaks at 398 nm, 410 nm, 451 nm, 469 nm, 484 nm, 493 nm and 545 nm at an excitation wavelength of 225 nm, which arises mainly due to oxygen and zinc related defects. The TL glow curve shows intense glow peaks at 346°, 261°, 209° and 153° for the samples synthesized at pH 3, pH 5, pH 7 and pH 9 respectively. The peaks are found to be increased with higher pH values. The peaks are found to be shifted towards lower temperature with higher pH values. The study shows that the ZnO–SnO 2 nano-composite is more developed material than singly ZnO compound or SnO 2 with enhanced opto-electronic and thermal properties and great applications in thermal dosimetry. - Highlights: • ZnO–CNT nanocomposites prepared by coprecipitation method at different pH values. • Sample at different pH show different nanostructures as revealed by SEM. • PL spectra indicate intense peaks related to O 2 and Zn defects for all samples. • TL spectra show peak shift with increasing pH values of samples. • ZnO–CNTs are very effective for both

Structural and optical properties of Cu2ZnSnS4 thin film absorbers from ZnS and Cu3SnS4 nanoparticle precursors

International Nuclear Information System (INIS)

Lin, Xianzhong; Kavalakkatt, Jaison; Kornhuber, Kai; Levcenko, Sergiu; Lux-Steiner, Martha Ch.; Ennaoui, Ahmed

2013-01-01

Cu 2 ZnSnS 4 (CZTS) has been considered as an alternative absorber layer to Cu(In,Ga)Se 2 due to its earth abundant and environmentally friendly constituents, optimal direct band gap of 1.4–1.6 eV and high absorption coefficient in the visible range. In this work, we propose a solution-based chemical route for the preparation of CZTS thin film absorbers by spin coating of the precursor inks composed of Cu 3 SnS 4 and ZnS NPs and annealing in Ar/H 2 S atmosphere. X-ray diffraction and Raman spectroscopy were used to characterize the structural properties. The chemical composition was determined by energy dispersive X-ray spectroscopy. Optical properties of the CZTS thin film absorbers were studied by transmission, reflection and photoluminescence spectroscopy

Effect of Low Concentration Sn Doping on Optical Properties of CdS Films Grown by CBD Technique

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Mohd Sabri Mohd Ghazali

2011-09-01

Full Text Available Thin and transparent films of doped cadmium sulfide (CdS were obtained on commercial glass substrates by Chemical Bath Deposition (CBD technique. The films were doped with low concentration of Sn, and annealed in air at 300 °C for 45 min. The morphological characterization of the films with different amounts of dopant was made using SEM and EDAX analysis. Optical properties of the films were evaluated by measuring transmittance using the UV-vis spectrophotometer. A comparison of the results revealed that lower concentration of Sn doping improves transmittance of CdS films and makes them suitable for application as window layer of CdTe/CIGS solar cells.

Premaximum observations of the type Ia SN 1990N

International Nuclear Information System (INIS)

Leibundgut, B.; Kirshner, R.P.; Filippenko, A.V.; Shields, J.C.; Foltz, C.B.; Phillips, M.M.; Sonneborn, G.

1991-01-01

Spectroscopic and photometric observations of SN 1990N were obtained at ultraviolet and optical wavelengths, beginning 14 days before maximum light. The early observations reveal important differences from spectra of SN Ia's around maximum light. Photometry and spectroscopy obtained after maximum show that SN 1990N is a typical SN Ia and that most of the observed differences are due to the early epoch of the observations. The most significant characteristics are (1) the high velocities of Ca and Si up to 22,000 km/s; (2) the presence of Co and Fe 2 weeks before maximum; and (3) the more rapid increase in the UV flux compared to the optical. The most popular models for white dwarf deflagration that have provided the standard interpretation for SN Ia's at maximum light do not reproduce the high velocities of Ca II and Si II lines observed in SN 1990N. 37 refs

Tree-like SnO2 nanowires and optical properties

International Nuclear Information System (INIS)

Tao Tao; Chen Qiyuan; Hu Huiping; Chen Ying

2011-01-01

Research highlights: → Tree-like SnO 2 nanowires can be grown as low as 1100 deg. C by a vapour-solid process using a milled SnO 2 powder as the evaporation source. → FT-IR and PL measurements have shown that the tree-like nanostructures lead to superb physical properties. → The PL spectrum of such tree-like nanowires exhibits a strong PL peak at 548 nm. - Abstract: Tree-like SnO 2 nanowires have been grown by a vapor-solid process using a milled SnO 2 powder as the evaporation source. Phase, structural evolution and chemical composition were investigated using X-ray diffraction (XRD), X-ray spectrometry (EDS), and scanning electron microscopy (SEM). The process yields a large proportion of ultra-long rutile nanowires of 50-150 nm diameter and lengths up to several tens of micrometers. High-resolution transmission electron microscopy (HRTEM) shows that the SnO 2 nanowires are single crystals in the (1 0 1) growth direction with scattered smaller crystals or nanowires as the tree branches. The SnO 2 nanostructures were also examined using Fourier transform infra-red (FT-IR) and photoluminescence (PL) spectroscopy. A strong emission band centered at 548 nm dominated the PL spectrum of the tree-like nanowires.

Effect of various SnO2 pH on ZnO/SnO2-composite film via immersion technique

Science.gov (United States)

Malek, M. F.; Mohamed, R.; Mamat, M. H.; Ismail, A. S.; Yusoff, M. M.; Rusop, M.

2018-05-01

ZnO/SnO2-composite film has been synthesized via immersion technique with various pH of SnO2. The pH of SnO2 were varied between 4.5 and 6.5. The optical measurements of the samples were carried out using Varian Cary 5000 UV-Vis spectrophotometer within the range from 350 nm to 800 nm at room temperature in air with a data interval of 1 nm. On the other hand, the optical photoluminescence properties were measured by a photoluminescence spectrometer (PL, model: Horiba Jobin Yvon - 79 DU420A-OE-325) using a He-Cd laser as the excitation source at 325 nm. These highly oriented ZnO/SnO2-composite film are potential for the creation of functional materials, such as the sensors, solar cells and etc.

Structure and optical band gaps of (Ba,Sr)SnO{sub 3} films grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Schumann, Timo; Raghavan, Santosh; Ahadi, Kaveh; Kim, Honggyu; Stemmer, Susanne, E-mail: stemmer@mrl.ucsb.edu [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

2016-09-15

Epitaxial growth of (Ba{sub x}Sr{sub 1−x})SnO{sub 3} films with 0 ≤ x ≤ 1 using molecular beam epitaxy is reported. It is shown that SrSnO{sub 3} films can be grown coherently strained on closely lattice and symmetry matched PrScO{sub 3} substrates. The evolution of the optical band gap as a function of composition is determined by spectroscopic ellipsometry. The direct band gap monotonously decreases with x from to 4.46 eV (x = 0) to 3.36 eV (x = 1). A large Burnstein-Moss shift is observed with La-doping of BaSnO{sub 3} films. The shift corresponds approximately to the increase in Fermi level and is consistent with the low conduction band mass.

The electrical, optical, structural and thermoelectrical characterization of n- and p-type cobalt-doped SnO2 transparent semiconducting films prepared by spray pyrolysis technique

International Nuclear Information System (INIS)

Bagheri-Mohagheghi, Mohammad-Mehdi; Shokooh-Saremi, Mehrdad

2010-01-01

The electrical, optical and structural properties of Cobalt (Co) doped SnO 2 transparent semiconducting thin films, deposited by the spray pyrolysis technique, have been studied. The SnO 2 :Co films, with different Co-content, were deposited on glass substrates using an aqueous-ethanol solution consisting of tin and cobalt chlorides. X-ray diffraction studies showed that the SnO 2 :Co films were polycrystalline only with tin oxide phases and preferential orientations along (1 1 0) and (2 1 1) planes and grain sizes in the range 19-82 nm. Optical transmittance spectra of the films showed high transparency ∼75-90% in the visible region, decreasing with increase in Co-doping. The optical absorption edge for undoped SnO 2 films was found to be 3.76 eV, while for higher Co-doped films shifted toward higher energies (shorter wavelengths) in the range 3.76-4.04 eV and then slowly decreased again to 4.03 eV. A change in sign of the Hall voltage and Seebeck coefficient was observed for a specific acceptor dopant level ∼11.4 at% in film and interpreted as a conversion from n-type to p-type conductivity. The thermoelectric electro-motive force (e.m.f.) of the films was measured in the temperature range 300-500 K and Seebeck coefficients were found in the range from -62 to +499 μVK -1 for various Co-doped SnO 2 films.

The electrical, optical, structural and thermoelectrical characterization of n- and p-type cobalt-doped SnO 2 transparent semiconducting films prepared by spray pyrolysis technique

Science.gov (United States)

Bagheri-Mohagheghi, Mohammad-Mehdi; Shokooh-Saremi, Mehrdad

2010-10-01

The electrical, optical and structural properties of Cobalt (Co) doped SnO 2 transparent semiconducting thin films, deposited by the spray pyrolysis technique, have been studied. The SnO 2:Co films, with different Co-content, were deposited on glass substrates using an aqueous-ethanol solution consisting of tin and cobalt chlorides. X-ray diffraction studies showed that the SnO 2:Co films were polycrystalline only with tin oxide phases and preferential orientations along (1 1 0) and (2 1 1) planes and grain sizes in the range 19-82 nm. Optical transmittance spectra of the films showed high transparency ∼75-90% in the visible region, decreasing with increase in Co-doping. The optical absorption edge for undoped SnO 2 films was found to be 3.76 eV, while for higher Co-doped films shifted toward higher energies (shorter wavelengths) in the range 3.76-4.04 eV and then slowly decreased again to 4.03 eV. A change in sign of the Hall voltage and Seebeck coefficient was observed for a specific acceptor dopant level ∼11.4 at% in film and interpreted as a conversion from n-type to p-type conductivity. The thermoelectric electro-motive force (e.m.f.) of the films was measured in the temperature range 300-500 K and Seebeck coefficients were found in the range from -62 to +499 μVK -1 for various Co-doped SnO 2 films.

Effect of Mn doping on the structural, magnetic, optical and electrical properties of ZrO_2–SnO_2 thin films prepared by sol–gel method

International Nuclear Information System (INIS)

Anitha, V.S.; Sujatha Lekshmy, S.; Joy, K.

2016-01-01

Manganese doped ZrO_2–SnO_2 (ZrO_2–SnO_2: Mn) nanocomposite thin films were prepared using sol – gel dip coating technique. The structural, morphological, magnetic, optical and electrical properties of the films were studied for undoped and different (15 mol %) manganese doping concentrations. X-ray diffraction pattern (XRD) of films showed the formation of tetragonal phase of SnO_2 and orthorhombic ZrSnO_4. Decrease in crystallinity with increase of Mn concentration was observed for the films. Scanning electron microscopy (SEM) showed the formation of grain growth with an increase in Mn concentration. X-ray photo electron spectroscopy (XPS) confirmed the presence of Zr"4"+, Sn"4"+ and Mn"2"+ ion in ZrO_2–SnO_2: Mn films. Vibrating sample magnetometer (VSM) measurements reveal the presence of magnetic properties in Mn doped nanocomposite thin films. Antiferromagnetic interactions were observed for 5 mol % Mn doping. An average transmittance >80% (UV - Vis region) was observed for all the films. Band gap of the films decreased from 4.78 to 4.41 eV with increase in Mn concentration. Photoluminescence (PL) spectra of the films exhibited emission peaks in visible region of the electromagnetic spectra. Conductivity of the film increased up to 3 mol % Mn doping and then decreased. - Highlights: • ZrO_2–SnO_2: Mn films were deposited onto quartz substrates by Sol –Gel dip coating. • Structural, magnetic, optical and electrical properties of the films were analyzed. • Optical band gap decreased with increase in manganese concentration. • Ferromagnetic behavior was observed for Mn doped films. • These ferromagnetic ZrO_2–SnO_2: Mn films find application in spintronic devices.

Tuning the optical bandgap in multi-cation compound transparent conducting-oxides: The examples of In2ZnO4 and In4Sn3O12

Science.gov (United States)

Sabino, Fernando P.; Oliveira, Luiz N.; Wei, Su-Huai; Da Silva, Juarez L. F.

2018-02-01

Transparent conducting oxides such as the bixbyite In2O3 and rutile SnO2 systems have large disparities between the optical and fundamental bandgaps, ΔEgO F , because selection rules forbid dipolar transitions from the top of the valence band to the conduction-band minimum; however, the optical gaps of multi-cation compounds with the same chemical species often coincide with their fundamental gaps. To explain this conundrum, we have employed density-functional theory to compute the optical properties of multi-cation compounds, In2ZnO4 and In4Sn3O12, in several crystal structures. We show that a recently proposed mechanism to explain the disparity between the optical and fundamental gaps of M2O3 (M = Al, Ga, and In) applies also to other binary systems and to multi-compounds. Namely, a gap disparity will arise if the following three conditions are satisfied: (i) the crystal structure has inversion symmetry; (ii) the conduction-band minimum is formed by the cation and O s-orbitals; and (iii) there is strong p-d coupling and weak p-p in the vicinity of the valence-band maximum. The third property depends critically on the cationic chemical species. In the structures with inversion symmetry, Zn (Sn) strengthens (weakens) the p-d coupling in In2ZnO4 (In4Sn3O12), enhancing (reducing) the gap disparity. Furthermore, we have also identified a In4Sn3O12 structure that is 31.80 meV per formula unit more stable than a recently proposed alternative model.

Optically stimulated luminescence in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass

Science.gov (United States)

Nanto, H.; Nakagawa, R.; Takei, Y.; Hirasawa, K.; Miyamoto, Y.; Masai, H.; Kurobori, T.; Yanagida, T.; Fujimoto, Y.

2015-06-01

An intense optically stimulated luminescence (OSL) was observed, for the first time, in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass. It was found that the peak wavelength of OSL emission spectrum and its stimulation spectrum is about 400 nm and 600 nm, respectively. The OSL intensity is depended on the SnO contents (x=0.05-1.5) and the most intense OSL was observed in 1.0 mol% SnO doped glass. It was found that the OSL intensity is increased with increasing x-ray absorbed dose. Fairly good fading characteristics were observed in the x-ray irradiated glass, showing that this glass is useful as a candidate for OSL sensor materials for ionizing radiation monitoring.

Physical Properties of the X-Ray-Luminous SN 1978K in NGC 1313 from Multiwavelength Observations

Science.gov (United States)

Schlegel, Eric M.; Ryder, Stuart; Staveley-Smith, L.; Petre, R.; Colbert, E.; Dopita, M.; Campbell-Wilson, D.

1999-12-01

We update the light curves from the X-ray, optical, and radio bandpasses which we have assembled over the past decade and present two observations in the ultraviolet using the Hubble Space Telescope Faint Object Spectrograph. The HRI X-ray light curve is constant within the errors over the entire observation period. This behavior is confirmed in the ASCA GIS data obtained in 1993 and 1995. In the ultraviolet, we detected Lyα, the [Ne IV] 2422/2424 Å doublet, the Mg II doublet at 2800 Å, and a line at approximately 3190 Å that we attribute to He I 3187. Only the Mg II and He I lines are detected at SN 1978K's position. The optical light curve is formally constant within the errors, although a slight upward trend may be present. The radio light curve continues its steep decline. The longer time span of our radio observations compared to previous studies shows that SN 1978K is in the same class of highly X-ray and radio-luminous supernovae as SN 1986J and SN 1988Z. The [Ne IV] emission is spatially distant from the location of SN 1978K and originates in the preshocked matter. The Mg II doublet flux ratio implies the quantity of line optical depth times density of approximately 1014 cm-3 for its emission region. The emission site must lie in the shocked gas.

Optical and electrochemical studies of polyaniline/SnO2 fibrous nanocomposites

International Nuclear Information System (INIS)

Manivel, P.; Ramakrishnan, S.; Kothurkar, Nikhil K.; Balamurugan, A.; Ponpandian, N.; Mangalaraj, D.; Viswanathan, C.

2013-01-01

Graphical abstract: Fiber with porous like structure of PANI/SnO 2 nanocomposites were prepared by simplest in situ chemical polymerization method. The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The excellent electrochemical properties of composite electrode show the specific capacitance of 173 F/g at a scan rate of 25 m V/s. Display Omitted Highlights: ► Self assembled PANI/SnO 2 nanocomposites were synthesized by simple polymerization method. ► Electrochemical behavior of PANI/SnO 2 nanocomposites electrode was analyzed by CV. ► Nanocomposites exhibit a higher specific capacitance of 173 F/g, compared with pure SnO 2 . -- Abstract: Polyaniline (PANI)/tin oxide (SnO 2 ) fibrous nanocomposites were successfully prepared by an in situ chemical polymerization method with suitable conditions. The obtained composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, photoluminescence (PL), electrical conductivity and cyclic voltammetry studies (CV). The XRD pattern of the as-prepared sample shows the presence of tetragonal SnO 2 and the crystalline structure of SnO 2 was not affected with the incorporation of PANI. The FTIR analysis confirms the uniform attachment of PANI on the surface of SnO 2 nanostructures. SEM images show a fibrous agglomerated structure of PANI/SnO 2 . The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The electrochemical behavior of the PANI/SnO 2 composite electrode was evaluated in a H 2 SO 4 solution using cyclic voltammetry. The composite electrode exhibited a specific capacitance of 173 F/g at a scan rate 25 mV/s. Thus the as-prepared PANI/SnO 2 composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.

Ultrasonic synthesis of In-doped SnS nanoparticles and their physical properties

Science.gov (United States)

Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin

2018-05-01

Indium (In)-doped Tin (II) Sulfide (SnS) nanoparticles (NPs) were synthesized by an ultra-sonication method and their optical, electrical, dielectric and photocatalytic properties were investigated. XRD patterns of the obtained NPs indicated formation of orthorhombic polycrystalline SnS. Field emission scanning electron microscopy exhibited flower-like NPs with particle sizes below 100 nm for both SnS and In-doped SnS samples. Optical analysis showed a decrease in energy band gap of SnS NPs upon In doping. In addition, electrical results demonstrated p-type nature of the synthesized SnS NPs and enhanced electrical conductivity of the NPs due to increased tin vacancy. Dielectric experiments on SnS NPs suggested an electronic polarizations effect to be responsible for changing dielectric properties of the particles, in terms of frequency. Finally, photocatalytic experiments revealed that high degradation power can be obtained using In-doped SnS NPs.

Electrical and optical characteristics of ITO films by pulsed laser deposition using a 10 wt.% SnO2-doped In2O3 ceramic target

International Nuclear Information System (INIS)

Kim, Sang Hyeob; Park, Nae-Man; Kim, TaeYoub; Sung, GunYong

2005-01-01

We have investigated the effect of the oxygen pressure and the deposition temperature on the electrical and optical properties of the Sn-doped indium oxide (ITO) films on quartz glass substrate by pulsed laser deposition (PLD) using a 10 wt.% SnO 2 -doped In 2 O 3 target. The resistivity and the carrier concentration of the films were decreased due to the decrease of the oxygen vacancy while increasing the oxygen pressure. With increasing deposition temperature, the resistivity of the films was decreased and the carrier concentration was increased due to the grain growth and the enhancement of the Sn diffusion. We have optimized the PLD process to deposit a highly conductive and transparent ITO film, which shows the optical transmittance of 88% and the resistivity of 2.49x10 -4 Ω cm for the film thickness of 180 nm

Optical characteristic and gap states distribution of amorphous SnO2:(Zn, In) film

International Nuclear Information System (INIS)

Zhang Zhi-Guo

2010-01-01

In this paper the fabrication technique of amorphous SnO 2 :(Zn, In) film is presented. The transmittance and gap-states distribution of the film are given. The experimental results of gap-states distribution are compared with the calculated results by using the facts of short range order and lattice vacancy defect of the gap states theory. The distribution of gap state has been proved to be discontinuous due to the short-range order of amorphous structure. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Structural and optical properties of Cu2SnS3 thin films obtained by SILAR method

Directory of Open Access Journals (Sweden)

Aykut ASTAM

2017-06-01

Full Text Available Cu2SnS3 thin films were obtained by annealing of SILAR deposited films at 350°C for 1 hour in sulphur atmosphere. The structural and optical properties of the films were investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray analysis (EDAX and optical absorption measurements, before and after annealing. The XRD results showed that the annealing process transformed the crystal structure of the films from amorphous to polycrystalline. SEM images revealed that the surface morphology of films was changed after annealing while EDAX analysis showed that the films were excess in copper concentration before and after annealing. Optical absorption measurements confirmed that the direct band gap of films decreased from 1.27 eV to 1.21 eV with annealing.

Effect of substrate temperature on structural and optical properties of nitrogen doped SnO2 thin film

International Nuclear Information System (INIS)

Thakur, Anup; Kumar, Varinder; Kang, Se Jun; Lee, Ik-Jae; Gautam, Sanjeev; Chae, K. H.; Shin, Hyun Joon

2014-01-01

Nitrogen doped SnO 2 thin films (thickness ∼ 250 nm) were deposited at different substrate temperature by radio frequency (rf) sputtering method. Crystal structure, morphology and optical properties of these films were investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and UV-VIS-NIR spectrophotometer, respectively. XRD measurement suggests that the film deposited at room temperature was amorphous in nature and films deposited at higher temperature were crystalline in nature. The film deposited at RT and 200 °C have transparency more than 90% in visible region but the film deposited at 400 °C has lesser transparency. Red shift was observed in the absorption edge may be due to decrease in ionicity due to the formation of the Sn-N bond

Synthesis of Nanocrystalline SnOx (x = 1–2 Thin Film Using a Chemical Bath Deposition Method with Improved Deposition Time, Temperature and pH

Directory of Open Access Journals (Sweden)

Zulkarnain Zainal

2011-09-01

Full Text Available Nanocrystalline SnOx (x = 1–2 thin films were prepared on glass substrates by a simple chemical bath deposition method. Triethanolamine was used as complexing agent to decrease time and temperature of deposition and shift the pH of the solution to the noncorrosive region. The films were characterized for composition, surface morphology, structure and optical properties. X-ray diffraction analysis confirms that SnOx thin films consist of a polycrystalline structure with an average grain size of 36 nm. Atomic force microscopy studies show a uniform grain distribution without pinholes. The elemental composition was evaluated by energy dispersive X-ray spectroscopy. The average O/Sn atomic percentage ratio is 1.72. Band gap energy and optical transition were determined from optical absorbance data. The film was found to exhibit direct and indirect transitions in the visible spectrum with band gap values of about 3.9 and 3.7 eV, respectively. The optical transmittance in the visible region is 82%. The SnOx nanocrystals exhibit an ultraviolet emission band centered at 392 nm in the vicinity of the band edge, which is attributed to the well-known exciton transition in SnOx. Photosensitivity was detected in the positive region under illumination with white light.

SN 2009bb: A PECULIAR BROAD-LINED TYPE Ic SUPERNOVA ,

International Nuclear Information System (INIS)

Pignata, Giuliano; Stritzinger, Maximilian; Phillips, M. M.; Morrell, Nidia; Boldt, Luis; Campillay, Abdo; Contreras, Carlos; Gonzalez, Sergio; Krzeminski, Wojtek; Roth, Miguel; Salgado, Francisco; Soderberg, Alicia; Mazzali, Paolo; Anderson, J. P.; Folatelli, Gaston; Foerster, Francisco; Hamuy, Mario; Maza, Jose; Levesque, Emily M.; Rest, Armin

2011-01-01

Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudobolometric light curve of SN 2009bb suggests that 4.1 ± 1.9 M sun of material was ejected with 0.22 ± 0.06 M sun of it being 56 Ni. The resulting kinetic energy is 1.8 ± 0.7 x 10 52 erg. This, together with an absolute peak magnitude of M B = -18.36 ± 0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for gamma-ray bursts (GRBs), we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of γ-ray instruments.

Optical fiber stripper positioning apparatus

Science.gov (United States)

Fyfe, Richard W.; Sanchez, Jr., Amadeo

1990-01-01

An optical fiber positioning apparatus for an optical fiber stripping device is disclosed which is capable of providing precise axial alignment between an optical fiber to be stripped of its outer jacket and the cutting blades of a stripping device. The apparatus includes a first bore having a width approximately equal to the diameter of an unstripped optical fiber and a counter bore axially aligned with the first bore and dimensioned to precisely receive a portion of the stripping device in axial alignment with notched cutting blades within the stripping device to thereby axially align the notched cutting blades of the stripping device with the axis of the optical fiber to permit the notched cutting blades to sever the jacket on the optical fiber without damaging the cladding on the optical fiber. In a preferred embodiment, the apparatus further includes a fiber stop which permits determination of the length of jacket to be removed from the optical fiber.

Impact of deposition temperature on the properties of SnS thin films grown over silicon substrate—comparative study of structural and optical properties with films grown on glass substrates

Science.gov (United States)

Assili, Kawther; Alouani, Khaled; Vilanova, Xavier

2017-11-01

Tin sulfide (SnS) thin films were chemically deposited over silicon substrate in a temperature range of 250 °C-400 °C. The effects of deposition temperature on the structural, morphological and optical properties of the films were evaluated. All films present an orthorhombic SnS structure with a preferred orientation along (040). High absorption coefficients (in the range of 105 cm-1) were found for all obtained films with an increase in α value when deposition temperature decreases. Furthermore, the effects of substrate type were investigated based on comparison between the present results and those obtained for SnS films grown under the same deposition conditions but over glass substrate. The results suggest that the formation of SnS films onto glass substrate is faster than onto silicon substrate. It is found that the substrate nature affects the orientation growth of the films and that SnS films deposited onto Si present more defects than those deposited onto glass substrate. The optical transmittance is also restricted by the substrate type, mostly below 1000 nm. The obtained results for SnS films onto silicon suggest their promising integration within optoelectronic devices.

Annealing of SnO2 thin films by ultra-short laser pulses

NARCIS (Netherlands)

Scorticati, D.; Illiberi, A.; Bor, T.; Eijt, S.W.H.; Schut, H.; Römer, G.R.B.E.; Lange, D.F. de; Huis In't Veld, A.J.

2014-01-01

Post-deposition annealing by ultra-short laser pulses can modify the optical properties of SnO2 thin films by means of thermal processing. Industrial grade SnO2 films exhibited improved optical properties after picosecond laser irradiation, at the expense of a slightly increased sheet resistance

Optical analysis of lens-like Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures

Energy Technology Data Exchange (ETDEWEB)

Odeh, Ali Abu; Ayub, R.M. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); Al-Douri, Y. [University Malaysia Perlis, Institute of Nano Electronic Engineering, Kangar, Perlis (Malaysia); University of Sidi-Bel-Abbes, Physics Department, Faculty of Science, Sidi-Bel-Abbes (Algeria); Ameri, M. [Universite Djilali Liabes de Sidi Bel- Abbes, Laboratoire Physico-Chimie des Materiaux Avances (LPCMA), Sidi-Bel-Abbes (Algeria); Bouhemadou, A. [University of Setif 1, Laboratory for Developing New Materials and Their Characterization, Setif (Algeria); Prakash, Deo [SMVD University, Faculty of Engineering, School of Computer Science and Engineering, Kakryal, Katra, J and K (India); Verma, K.D. [S.V. College, Material Science Research Laboratory, Department of Physics, Aligarh, U.P. (India)

2016-10-15

Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures with different copper concentrations (0.2, 0.4, 0.6, 0.8 and 1.0 M) were successfully synthesized on n-type silicon substrates using spin coating technique with annealing temperature at 300 C. Optical properties were analyzed through UV-Vis and Photoluminescence spectroscopies, and thus, there is a change in energy band gap with increasing Cu concentration from 0.2 to 1.0 M. The structural properties of Cu{sub 2}CdSnS{sub 4} quaternary alloy nanostructures were investigated by X-ray diffraction. The particles size and shape have a direct relationship with copper concentration. Morphological and topographical studies were carried out by using scanning electron microscopy and atomic force microscopy. The obtained results are investigated to be available in the literature for future studies. (orig.)

Structure and optical properties of [In{sub 1−2x}Sn{sub x}Zn{sub x}]GaO{sub 3}(ZnO){sub m}

Energy Technology Data Exchange (ETDEWEB)

Eichhorn, Simon; Mader, Werner, E-mail: mader@uni-bonn.de

2016-01-15

Compounds of [In{sub 1−2x}Sn{sub x}Zn{sub x}]GaO{sub 3}(ZnO){sub 1} (x≤0.22) and [In{sub 1−2x}Sn{sub x}Zn{sub x}]GaO{sub 3}(ZnO){sub 2} (x≤0.42) were prepared by solid state processing proving a substantial solid solution of Sn in the layered compounds InGaO{sub 3}(ZnO){sub m} (m=1, 2). Single crystal X-ray diffraction of the compounds reveals two In{sup 3+} ions to be substituted by one Sn{sup 4+} and one Zn{sup 2+} at the octahedral layer preserving the average charge of +3 at these sites. The substitution does not lead to an ordering of the ions but proves for the first time that the octahedral site can be occupied by different ions while all characteristics of the layered structures remain unchanged. Consequences of indium substitution are (i) decrease of the a axis compared to InGaO{sub 3}(ZnO){sub m} according to smaller ionic radii of Sn{sup 4+} and Zn{sup 2+} compared to In{sup 3+} and (ii) shift of the optical band gap to higher energies shown by UV–vis measurements. - Graphical abstract: Substitution limits of indium in InGaO{sub 3}(ZnO){sub m} (IGZO) by Sn and Zn are studied for m=1, 2 by single crystal X-ray diffraction and micro-chemical analysis. - Highlights: • New Oxides [In{sub 1−2x}Sn{sub x}Zn{sub x}]GaO{sub 3}(ZnO){sub m} (m=1, 2) with IGZO type structure. • Sn and Zn substitute for In at octahedral sites. • Crystal structures were characterized by single crystal X-ray diffraction. • Optical band gap energies were determined by UV–vis spectroscopy.

Towards from indirect to direct band gap and optical properties of XYP{sub 2} (X=Zn, Cd; Y=Si, Ge, Sn)

Energy Technology Data Exchange (ETDEWEB)

Ullah, Sibghat [Department of Physics, Hazara University Mansehra, KPK (Pakistan); Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Lab, Department of Physics, Islamia College, Peshawar (Pakistan); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 Mascara (Algeria); Reshak, A.H. [New Technologies—Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Hayat, S.S. [Department of Physics, Hazara University Mansehra, KPK (Pakistan); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

2014-05-15

First principle calculations are performed to predict the electronic and optical properties of XYP{sub 2} (X=Zn, Cd; Y=Si, Ge, Sn) compounds. The calculations show an excellent agreement with the available experimental results as compared to previous calculations. The band gap value decreases by changing the cations X from Zn to Cd as well as Y from Si to Ge to Sn in XYP{sub 2}. The d-states of the Zn and Cd contribute majorly in the density of states. Bonding nature in these compounds is analyzed from the electron density plots. Optical response of these compounds is noted from the complex refractive index and reflectivity spectra. The wide direct band gap and the high reflectivity in the visible and ultraviolet regions for these compounds make them potential candidates for optoelectronic and photonic applications.

Effect of indium and antimony doping in SnS single crystals

Energy Technology Data Exchange (ETDEWEB)

Chaki, Sunil H., E-mail: sunilchaki@yahoo.co.in; Chaudhary, Mahesh D.; Deshpande, M.P.

2015-03-15

Highlights: • Single crystals growth of pure SnS, indium doped SnS and antimony doped SnS by direct vapour transport (DVT) technique. • Doping of In and Sb occurred in SnS single crystals by cation replacement. • The replacement mechanism ascertained by EDAX, XRD and substantiated by Raman spectra analysis. • Dopants concentration affects the optical energy bandgap. • Doping influences electrical transport properties. - Abstract: Single crystals of pure SnS, indium (In) doped SnS and antimony (Sb) doped SnS were grown by direct vapour transport (DVT) technique. Two doping concentrations of 5% and 15% each were employed for both In and Sb dopants. Thus in total five samples were studied viz., pure SnS (S1), 5% In doped SnS (S2), 15% In doped SnS (S3), 5% Sb doped SnS (S4) and 15% Sb doped SnS (S5). The grown single crystal samples were characterized by evaluating their surface microstructure, stoichiometric composition, crystal structure, Raman spectroscopy, optical and electrical transport properties using appropriate techniques. The d.c. electrical resistivity and thermoelectric power variations with temperature showed semiconducting and p-type nature of the as-grown single crystal samples. The room temperature Hall Effect measurements further substantiated the semiconducting and p-type nature of the as-grown single crystal samples. The obtained results are deliberated in detail.

SN 1987A. Theory

International Nuclear Information System (INIS)

Schaeffer, R.

1987-03-01

SN 1987A was unique in many aspects. The most striking, undoubtedly, is its low luminosity, nearly two orders of magnitude below the expectations based on supernovae currently observed in external galaxies. The rise time of the optical emission, usually a few days, was for SN 1987A, of the order of a few hours. Also its surface temperature is surprisingly low, 5000K. The neutrino burst has been detected. It was observed twice, with a time difference of 5 hours, the second burst occurring within 3 hours of the onset of the optical signal. In this talk, I will discuss how these strange events fit with the theoretical models of supernova explosions, how they differ in some cases, and try to evaluate the degree of certainty -or uncertainty- of our present knowledge on how these extremely powerful star explosions occur

Structural, optical and gas sensing properties of screen-printed nanostructured Sr-doped SnO2 thick film sensor

International Nuclear Information System (INIS)

Shaikh, F.I.; Chikhale, L.P.; Patil, J.Y.; Rajgure, A.V.; Suryavanshi, S.S.; Mulla, I.S.

2013-01-01

The nanocrystalline materials of strontium doped tin oxide powders were synthesized by conventional co-precipitation method. Synthesized nanophase SnO 2 powders were used to fabricate thick films of pure and Sr-doped SnO 2 using screen-printing technology and investigated for their gas sensing properties towards LPG, ethanol, ammonia and acetone vapor. The crystal structure and phase of the sintered powders were characterized by X-ray diffractometer (XRD) and microstructure by scanning electron microscopy (SEM). All the doped and undoped SnO 2 compositions revealed single phase and solid solution formation. X-ray diffractometer (XRD) results indicated that well crystallized Sr-doped SnO 2 particles of size about 10 nm were obtained at sintering temperature 700℃. The optical properties viz. UV-Vis, FTIR and Raman were used to characterize various physico-chemical properties of samples. The reduction of grain size in metal oxide is a key factor to enhance the gas sensing properties. The doping of Sr in SnO 2 has reduced the grain size and improved the gas response. The results of gas sensing measurements showed that the thick films deposited on alumina substrates using screen-printing technique exhibited high gas response, quick response time and fast recovery time to acetone gas at a working temperature of 250℃. Further, the selectivity of sensor towards acetone with respect to other reducing gases (LPG, ethanol, ammonia) was studied. (author)

Pseudomorphic GeSiSn, SiSn and Ge layers in strained heterostructures

Science.gov (United States)

Timofeev, V. A.; Nikiforov, A. I.; Tuktamyshev, A. R.; Mashanov, V. I.; Loshkarev, I. D.; Bloshkin, A. A.; Gutakovskii, A. K.

2018-04-01

The GeSiSn, SiSn layer growth mechanisms on Si(100) were investigated and the kinetic diagrams of the morphological GeSiSn, SiSn film states in the temperature range of 150 °C-450 °C at the tin content from 0% to 35% were built. The phase diagram of the superstructural change on the surface of Sn grown on Si(100) in the annealing temperature range of 0 °C-850 °C was established. The specular beam oscillations were first obtained during the SiSn film growth from 150 °C to 300 °C at the Sn content up to 35%. The transmission electron microscopy and x-ray diffractometry data confirm the crystal perfection and the pseudomorphic GeSiSn, SiSn film state, and also the presence of smooth heterointerfaces between GeSiSn or SiSn and Si. The photoluminescence for the multilayer periodic GeSiSn/Si structures in the range of 0.6-0.8 eV was detected. The blue shift with the excitation power increase is observed suggesting the presence of a type II heterostructure. The creation of tensile strained Ge films, which are pseudomorphic to the underlying GeSn layer, is confirmed by the results of the formation and analysis of the reciprocal space map in the x-ray diffractometry. The tensile strain in the Ge films reached the value in the range of 0.86%-1.5%. The GeSn buffer layer growth in the Sn content range from 8% to 12% was studied. The band structure of heterosystems based on pseudomorphic GeSiSn, SiSn and Ge layers was calculated and the valence and conduction band subband position dependences on the Sn content were built. Based on the calculation, the Sn content range in the GeSiSn, SiSn, and GeSn layers, which corresponds to the direct bandgap GeSiSn, SiSn, and Ge material, was obtained.

Comparison of two self-assembled macromolecular prodrug micelles with different conjugate positions of SN38 for enhancing antitumor activity

Directory of Open Access Journals (Sweden)

Liu Y

2015-03-01

Full Text Available Yi Liu,1 Hongyu Piao,1 Ying Gao,1 Caihong Xu,2 Ye Tian,1 Lihong Wang,1 Jinwen Liu,1 Bo Tang,1 Meijuan Zou,1 Gang Cheng1 1Department of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, People’s Republic of China; 2Department of Food Science, Shenyang Normal University, Shenyang, Liaoning Province, People’s Republic of China Abstract: 7-Ethyl-10-hydroxycamptothecin (SN38, an active metabolite of irinotecan (CPT-11, is a remarkably potent antitumor agent. The clinical application of SN38 has been extremely restricted by its insolubility in water. In this study, we successfully synthesized two macromolecular prodrugs of SN38 with different conjugate positions (chitosan-(C10-OHSN38 and chitosan-(C20-OHSN38 to improve the water solubility and antitumor activity of SN38. These prodrugs can self-assemble into micelles in aqueous medium. The particle size, morphology, zeta potential, and in vitro drug release of SN38 and its derivatives, as well as their cytotoxicity, pharmacokinetics, and in vivo antitumor activity in a xenograft BALB/c mouse model were studied. In vitro, chitosan-(C10-OHSN38 (CS-(10sSN38 and chitosan-(C20-OHSN38 (CS-(20sSN38 were 13.3- and 25.9-fold more potent than CPT-11 in the murine colon adenocarcinoma cell line CT26, respectively. The area under the curve (AUC0–24 of SN38 after intravenously administering CS-(10sSN38 and CS-(20sSN38 to Sprague Dawley rats was greatly improved when compared with CPT-11 (both P<0.01. A larger AUC0–24 of CS-(20sSN38 was observed when compared to CS-(10sSN38 (P<0.05. Both of the novel self-assembled chitosan-SN38 prodrugs demonstrated superior anticancer activity to CPT-11 in the CT26 xenograft BALB/c mouse model. We have also investigated the differences between these macromolecular prodrug micelles with regards to enhancing the antitumor activity of SN38. CS-(20sSN38 exhibited better in vivo antitumor activity than CS-(10sSN38 at a dose of 2.5 mg/kg (P<0

An open-framework bimetallic chalcogenide structure K3Rb3Zn4Sn3Se13 built on a unique [Zn4Sn3Se16]12- cluster: synthesis, crystal structure, ion exchange and optical properties

International Nuclear Information System (INIS)

Wu Min; Su Weiping; Jasutkar, Niren; Huang, Xiaoying; Li Jing

2005-01-01

Single crystals of K 3 Rb 3 Zn 4 Sn 3 Se 13 were synthesized by solvothermal method. The building block in this structure is a [Zn 4 Sn 3 Se 16 ] 12- cluster which consists of four ZnSe 4 and three SnSe 4 tetrahedra connected through corner-sharing of Se atoms. The 3D network contains intersecting channels running parallel to the crystallographic [2 1 1], [1-1-1] and [12-1] directions. The disordered K + and Rb + cations reside in these channels. Ion exchange of Cs + with disordered Rb + /K + ions in the structure showed a partial replacement of 15.8%. Optical diffuse reflectance experiments were carried out and gave a sharp absorption edge at 2.6 eV

SN 2012fr

DEFF Research Database (Denmark)

Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.

2018-01-01

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epo...

Ex situ n+ doping of GeSn alloys via non-equilibrium processing

Science.gov (United States)

Prucnal, S.; Berencén, Y.; Wang, M.; Rebohle, L.; Böttger, R.; Fischer, I. A.; Augel, L.; Oehme, M.; Schulze, J.; Voelskow, M.; Helm, M.; Skorupa, W.; Zhou, S.

2018-06-01

Full integration of Ge-based alloys like GeSn with complementary-metal-oxide-semiconductor technology would require the fabrication of p- and n-type doped regions for both planar and tri-dimensional device architectures which is challenging using in situ doping techniques. In this work, we report on the influence of ex situ doping on the structural, electrical and optical properties of GeSn alloys. n-type doping is realized by P implantation into GeSn alloy layers grown by molecular beam epitaxy (MBE) followed by flash lamp annealing. We show that effective carrier concentration of up to 1 × 1019 cm‑3 can be achieved without affecting the Sn distribution. Sn segregation at the surface accompanied with an Sn diffusion towards the crystalline/amorphous GeSn interface is found at P fluences higher than 3 × 1015 cm‑2 and electron concentration of about 4 × 1019 cm‑3. The optical and structural properties of ion-implanted GeSn layers are comparable with the in situ doped MBE grown layers.

SN 2009kn - the twin of the Type IIn supernova 1994W

DEFF Research Database (Denmark)

Kankare, E.; Ergon, M.; Bufano, F.

2012-01-01

We present an optical and near-infrared photometric and spectroscopic study of supernova (SN) 2009kn spanning ~1.5 yr from the discovery. The optical spectra are dominated by the narrow (full width at half-maximum ~1000 km s^-1) Balmer lines distinctive of a Type IIn SN with P Cygni profiles. Con...

Structural and optical properties of vanadium doped SnO{sub 2} nanoparticles with high photocatalytic activities

Energy Technology Data Exchange (ETDEWEB)

Reddy, Ch. Venkata [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Babu, B. [Department of Electronics and Computer Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Vattikuti, S.V. Prabhakar [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N. [Department of Physics, Acharya Nagarjuna University, Guntur, A.P. 522510 (India); Shim, Jaesool, E-mail: Jshim@ynu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

2016-11-15

Vanadium (0.01, 0.03 and 0.05 mol%) doped SnO{sub 2} nanoparticles have been synthesized using combustion synthesis method. The as-prepared nanoparticles were characterized using various measurements such as XRD, SEM with EDS, HRTEM, Raman spectroscopy, optical, PL, XPS and FT-IR techniques. The crystal structure and average particle sizes of the prepared nanoparticles were confirmed from the XRD. The average crystalline particle sizes were decreased by increasing the vanadium dopant concentration. The presence of vanadium as V{sup 4+} species in the host lattice was confirmed by X-ray photoelectron spectroscopy. The band gap energies were decreased by increasing dopant concentration. The 0.05 mol% doped sample showed higher photocatalytic activity than undoped, V-1 and V-3 in decomposing rhodamine B (RhB) under UV light irradiation. The Raman and IR spectra confirm the fundamental vibration of SnO{sub 2} host molecules.

ASAS-SN Discovery of an Unprecedented >1.5 Magnitude Optical Flare from QSO B0346-279

Science.gov (United States)

Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Shields, J. V.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.

2018-02-01

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, the quadruple 14-cm "Leavitt" telescope in Fort Davis, Texas, the quadruple 14-cm "Payne-Gaposchkin" telescope in Sutherland, South Africa, and the quadruple 14-cm "Cassius" and "Paczynski" telescopes in Cerro Tololo, Chile, we have discovered an unprecedented optical brightening of QSO B0346-279 (z 0.9874).

THE RISE OF SN 2014J IN THE NEARBY GALAXY M82

International Nuclear Information System (INIS)

Goobar, A.; Johansson, J.; Amanullah, R.; Ferretti, R.; Cao, Y.; Perley, D. A.; Tendulkar, S. P.; Kasliwal, M. M.; Nugent, P. E.; Harris, C.; Gal-Yam, A.; Ofek, E. O.; Dennefeld, M.; Valenti, S.; Arcavi, I.; Banerjee, D. P. K.; Venkataraman, V.; Joshi, V.; Ashok, N. M.; Cenko, S. B.

2014-01-01

We report on the discovery of SN 2014J in the nearby galaxy M82. Given its proximity, it offers the best opportunity to date to study a thermonuclear supernova (SN) over a wide range of the electromagnetic spectrum. Optical, near-IR, and mid-IR observations on the rising light curve, orchestrated by the intermediate Palomar Transient Factory, show that SN 2014J is a spectroscopically normal Type Ia supernova (SN Ia), albeit exhibiting high-velocity features in its spectrum and heavily reddened by dust in the host galaxy. Our earliest detections start just hours after the fitted time of explosion. We use high-resolution optical spectroscopy to analyze the dense intervening material and do not detect any evolution in the resolved absorption features during the light curve rise. Similar to other highly reddened SNe Ia, a low value of total-to-selective extinction, R V ≲ 2, provides the best match to our observations. We also study pre-explosion optical and near-IR images from Hubble Space Telescope with special emphasis on the sources nearest to the SN location

XRF 100316D/SN 2010bh AND THE NATURE OF GAMMA-RAY BURST SUPERNOVAE

International Nuclear Information System (INIS)

Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Melandri, A.; Mundell, C. G.; Levan, A. J.; Tanvir, N. R.; Wiersema, K.; D'Avanzo, P.; Margutti, R.; Fruchter, A. S.; Garnavich, P.; Gomboc, A.; Kopac, D.; Gorosabel, J.; Kasen, D.; Mazzali, P. A.; Nugent, P. E.; Pian, E.

2011-01-01

We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN that was spectroscopically linked with XRF 060218, and at a similar rate to the non-GRB associated Type Ic SN 1994I. We estimate the rest-frame extinction of this event from our optical data to be E(B - V) = 0.18 ± 0.08 mag. We find the V-band absolute magnitude of SN 2010bh to be M V = -18.62 ± 0.08, which is the faintest peak V-band magnitude observed to date for spectroscopically confirmed GRB-SNe. When we investigate the origin of the flux at t - t 0 = 0.598 days, it is shown that the light is not synchrotron in origin, but is likely coming from the SN shock breakout. We then use our optical and infrared data to create a quasi-bolometric light curve of SN 2010bh, which we model with a simple analytical formula. The results of our modeling imply that SN 2010bh synthesized a nickel mass of M Ni ∼ 0.1 M sun , ejected M ej ∼ 2.2 M sun , and has an explosion energy of E k ∼ 1.4 x 10 52 erg. Thus, while SN 2010bh is an energetic explosion, the amount of nickel created during the explosion is much less than that of SN 1998bw and only marginally more than SN 1994I. Finally, for a sample of 22 GRB-SNe we check for a correlation between the stretch factors and luminosity factors in the R band and conclude that no statistically significant correlation exists.

Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

Energy Technology Data Exchange (ETDEWEB)

Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

2009-05-27

The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

The Candidate Progenitor of the Type IIn SN 2010jl Is Not an Optically Luminous Star

Energy Technology Data Exchange (ETDEWEB)

Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dyk, Schuyler D. Van [IPAC/Caltech, Mailcode 100-22, Pasadena, CA 91125 (United States); Dwek, Eli [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 665, Greenbelt, MD 20771 (United States); Smith, Nathan; Andrews, Jennifer [Steward Observatory, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Filippenko, Alexei V.; Kelly, Patrick L.; Shivvers, Isaac [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Arendt, Richard G. [CRESST/UMBC/GSFC Code 665, NASA/GSFC, Greenbelt MD, 20771 (United States); Foley, Ryan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Miller, Adam A., E-mail: ofox@stsci.edu [Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 169-506, Pasadena, CA 91109 (United States)

2017-02-20

A blue source in pre-explosion Hubble Space Telescope ( HST )/Wide-Field Planetary Camera 2 (WFPC2) images falls within the 5 σ astrometric error circle (∼0.″24) derived from post-explosion ground-based imaging of SN 2010jl. At the time the ground-based astrometry was published, however, the SN had not faded sufficiently for post-explosion HST follow-up observations to determine a more precise astrometric solution and/or confirm if the pre-explosion source had disappeared, both of which are necessary to ultimately disentangle the possible progenitor scenarios. Here we present HST /WFC3 imaging of the SN 2010jl field obtained in 2014, 2015, and 2016 when the SN had faded sufficiently to allow for new constraints on the progenitor. The SN, which is still detected in the new images, is offset by 0.″061 ± 0.″008 (15 ± 2 pc) from the underlying and extended source of emission that contributes at least partially, if not entirely, to the blue source previously suggested as the candidate progenitor in the WFPC2 data. This point alone rules out the possibility that the blue source in the pre-explosion images is the exploding star, but may instead suggest an association with a young (<5–6 Myr) cluster and still argues for a massive (>30 M {sub ⊙}) progenitor. We obtain new upper limits on the flux from a single star at the SN position in the pre-explosion WFPC2 and Spitzer /IRAC images that may ultimately be used to constrain the progenitor properties.

The Candidate Progenitor of the Type IIn SN 2010jl Is Not an Optically Luminous Star

Science.gov (United States)

Fox, Ori D.; Van Dyk, Schuyler D.; Dwek, Eli; Smith, Nathan; Filippenko, Alexei V.; Andrews, Jennifer; Arendt, Richard G.; Foley, Ryan J.; Kelly, Patrick L.; Miller, Adam;

α-Eleostearic acid-containing triglycerides for a continuous assay to determine lipase sn-1 and sn-3 regio-preference.

Science.gov (United States)

El Alaoui, Meddy; Soulère, Laurent; Noiriel, Alexandre; Queneau, Yves; Abousalham, Abdelkarim

2017-08-01

Lipases are essentially described as sn-1 and sn-3 regio-selective. Actually few methods are available to measure this lipase regio-selectivity, moreover they require chiral chromatography analysis or specific derivations which are discontinuous and time consuming. In this study we describe a new, convenient, sensitive and continuous spectrophotometric method to screen lipases regio-selectivity using synthetic triglycerides (TG) containing α-eleostearic acid (9Z, 11E, 13E-octadecatrienoic acid) either at the sn-1 position [1-α-eleostearoyl-2,3-octadecyl-sn-glycerol (sn-EOO)] or at the sn-3 position [1,2-octadecyl-3-α-eleostearoyl-sn-glycerol (sn-OOE)] and coated onto the wells of microtiter plates. A non-hydrolysable ether bond, with a non UV-absorbing alkyl chain, was introduced at the other sn positions to prevent acyl chain migration during TG synthesis or lipolysis. The synthesis of TG containing α-eleostearic acid was performed from S-glycidol in six steps to obtain sn-EOO and in five steps to sn-OOE. The α-eleostearic acid conjugated triene constitutes an intrinsic chromophore and, consequently, confers the strong UV absorption properties of this free fatty acid as well as of the TG harboring it. The lipase activity on coated sn-EOO or sn-OOE was measured by the increase in the absorbance at 272nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. Human and porcine pancreatic lipases, guinea pig pancreatic lipase related protein 2, Thermomyces lanuginosus lipase, Candida antarctica lipase A and Candida antarctica lipase B were all used to validate the assay. This continuous high-throughput screening method could determine directly without any processes after lipolysis the regio-selectivity of various lipases. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and characterization of different morphological SnS nanomaterials

International Nuclear Information System (INIS)

Chaki, Sunil H; Chaudhary, Mahesh D; Deshpande, M P

2014-01-01

SnS in three nano forms possessing different morphologies such as particles, whiskers and ribbons were synthesised by chemical route. The morphology variation was brought about in the chemical route synthesis by varying a synthesis parameter such as temperature and influencing the synthesis by use of surfactant. The elemental composition determination by energy dispersive analysis of x-rays (EDAX) showed that all three synthesized SnS nanomaterials were tin deficient. The x-ray diffraction (XRD) study of the three SnS nanomaterials showed that all of them possess orthorhombic structure. The Raman spectra of the three SnS nanomaterials showed that all three samples possess three common distinguishable peaks. In them two peaks lying at 98 ± 1 cm −1 and 224 ± 4 cm −1 are the characteristic A g mode of SnS. The third peak lying at 302 ± 1 cm −1 is associated with secondary Sn 2 S 3 phase. The transmission electron microscopy (TEM) confirmed the respective morphologies. The optical analysis showed that they possess direct as well as indirect optical bandgap. The electrical transport properties study on the pellets prepared from the different nanomaterials of SnS showed them to be semiconducting and p-type in nature. The current–voltage (I–V) plots of the silver (Ag)/SnS nanomaterials pellets for dark and incandescent illumination showed that all configurations showed good ohmic behaviour except Ag/SnS nanoribbons pellet configuration under illumination. All the obtained results are discussed in detail. (paper)

SN 2006oz

DEFF Research Database (Denmark)

Leloudas, Georgios; Chatzopoulos, E.; Dilday, B.

2012-01-01

to contribute to a better understanding of these objects by studying SN 2006oz, a newly-recognized member of this class. Methods. We present multi-color light curves of SN 2006oz from the SDSS-II SN Survey that cover its rise time, as well as an optical spectrum that shows that the explosion occurred at z ~ 0.......376. We fitted black-body functions to estimate the temperature and radius evolution of the photosphere and used the parametrized code SYNOW to model the spectrum. We constructed a bolometric light curve and compared it with explosion models. In addition, we conducted a deep search for the host galaxy...... to a recombination wave in a circumstellar medium (CSM) and discuss whether this is a common property of all similar explosions. The subsequent rise can be equally well described by input from a magnetar or by ejecta-CSM interaction, but the models are not well constrained owing to the lack of post...

Phase composition of rapidly solidified Ag-Sn-Cu dental alloys

International Nuclear Information System (INIS)

Lecong Dzuong; Do Minh Nghiep; Nguyen van Dzan; Cao the Ha

1996-01-01

The phase composition of some rapidly solidified Ag-Sn-Cu dental alloys with different copper contents (6.22 wtpct) has been studied by XRD, EMPA and optical microscopy. The samples were prepared from melt-spun ribbons. The microstructure of the as-quenched ribbons was microcrystalline and consisted of the Ag sub 3 Sn, Ag sub 4 Sn, Cu sub 3 Sn and Cu sub 3 Sn sub 8 phases. Mixing with mercury (amalgamation) led to formation of the Ag sub 2 Hg sub 3, Sn sub 7 Hg and Cu sub 6 Sn sub 5 phases. The amount of copper atoms in the alloys played an important role in phase formation in the amalgams

ASYMMETRY IN THE OUTBURST OF SN 1987A DETECTED USING LIGHT ECHO SPECTROSCOPY

International Nuclear Information System (INIS)

Sinnott, B.; Welch, D. L.; Sutherland, P. G.; Rest, A.; Bergmann, M.

2013-01-01

We report direct evidence for asymmetry in the early phases of SN 1987A via optical spectroscopy of five fields of its light echo system. The light echoes allow the first few hundred days of the explosion to be reobserved, with different position angles providing different viewing angles to the supernova. Light echo spectroscopy therefore allows a direct spectroscopic comparison of light originating from different regions of the photosphere during the early phases of SN 1987A. Gemini multi-object spectroscopy of the light echo fields shows fine structure in the Hα line as a smooth function of position angle on the near-circular light echo rings. Hα profiles originating from the northern hemisphere of SN 1987A show an excess in redshifted emission and a blue knee, while southern hemisphere profiles show an excess of blueshifted Hα emission and a red knee. This fine structure is reminiscent of the 'Bochum event' originally observed for SN 1987A, but in an exaggerated form. Maximum deviation from symmetry in the Hα line is observed at position angles 16° and 186°, consistent with the major axis of the expanding elongated ejecta. The asymmetry signature observed in the Hα line smoothly diminishes as a function of viewing angle away from the poles of the elongated ejecta. We propose an asymmetric two-sided distribution of 56 Ni most dominant in the southern far quadrant of SN 1987A as the most probable explanation of the observed light echo spectra. This is evidence that the asymmetry of high-velocity 56 Ni in the first few hundred days after explosion is correlated to the geometry of the ejecta some 25 years later.

Synthesis and characterization of binary ZnO-SnO2 (ZTO) thin films by e-beam evaporation technique

Science.gov (United States)

Bibi, Shagufta; Shah, A.; Mahmood, Arshad; Ali, Zahid; Raza, Qaisar; Aziz, Uzma; Haneef; Waheed, Abdul; Shah, Ziaullah

2018-04-01

The binary ZnO-SnO2 (ZTO) thin films with varying SnO2 concentrations (5, 10, 15, and 20 wt%) were grown on glass substrate by e-beam evaporation technique. The prepared ZTO films were annealed at 400 °C in air. These films were then characterized to investigate their structural, optical, and electrical properties as a function of SnO2 concentration. XRD analysis reveals that the crystallinity of the film decreases with the addition of SnO2 and it transforms to an amorphous structure at a composition of 40% SnO2 and 60% ZnO. Morphology of the films was examined by atomic force microscopy which points out that surface roughness of the films decreases with the increasing of SnO2 in the film. Optical properties such as optical transparency, band-gap energy, and optical constants of these films were examined by spectrophotometer and spectroscopic Ellipsometer. It was observed that the average optical transmission of mixed films improves with incorporation of SnO2. In addition, the band-gap energy of the films was determined to be in the range of 3.37-3.7 eV. Furthermore, it was found that the optical constants (n and k) decrease with the addition of SnO2. Similarly, it is observed that the electrical resistivity increases nonlinearly with the increase in SnO2 in ZnO-SnO2 thin films. However, it is noteworthy that the highest figure of merit (FOM) value, i.e., 55.87 × 10-5 Ω-1, is obtained for ZnO-SnO2 (ZTO) thin film with 40 wt% of SnO2 composition. Here, we suggest that ZnO-SnO2 (ZTO) thin film with composition of 60:40 wt% can be used as an efficient TCO film due to the improved transmission, and reduced RMS value and highest FOM value.

Optical and electrochemical studies of polyaniline/SnO{sub 2} fibrous nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Manivel, P. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Ramakrishnan, S.; Kothurkar, Nikhil K. [Department of Chemical Engineering and Material Science, Amrita Vishwa Vidyapeetham, Coimbatore 641 112, Tamil Nadu (India); Balamurugan, A.; Ponpandian, N.; Mangalaraj, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Viswanathan, C., E-mail: viswanathan@buc.edu.in [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India)

2013-02-15

Graphical abstract: Fiber with porous like structure of PANI/SnO{sub 2} nanocomposites were prepared by simplest in situ chemical polymerization method. The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The excellent electrochemical properties of composite electrode show the specific capacitance of 173 F/g at a scan rate of 25 m V/s. Display Omitted Highlights: ► Self assembled PANI/SnO{sub 2} nanocomposites were synthesized by simple polymerization method. ► Electrochemical behavior of PANI/SnO{sub 2} nanocomposites electrode was analyzed by CV. ► Nanocomposites exhibit a higher specific capacitance of 173 F/g, compared with pure SnO{sub 2}. -- Abstract: Polyaniline (PANI)/tin oxide (SnO{sub 2}) fibrous nanocomposites were successfully prepared by an in situ chemical polymerization method with suitable conditions. The obtained composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, photoluminescence (PL), electrical conductivity and cyclic voltammetry studies (CV). The XRD pattern of the as-prepared sample shows the presence of tetragonal SnO{sub 2} and the crystalline structure of SnO{sub 2} was not affected with the incorporation of PANI. The FTIR analysis confirms the uniform attachment of PANI on the surface of SnO{sub 2} nanostructures. SEM images show a fibrous agglomerated structure of PANI/SnO{sub 2}. The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The electrochemical behavior of the PANI/SnO{sub 2} composite electrode was evaluated in a H{sub 2}SO{sub 4} solution using cyclic voltammetry. The composite electrode exhibited a specific capacitance of 173 F/g at a scan rate 25 mV/s. Thus the as-prepared PANI/SnO{sub 2} composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.

Zr-Sn-Nb alloys. Preliminary studies

International Nuclear Information System (INIS)

Danon, C.A.; Arias, D.E.

1993-01-01

Studies of the Zr-Sn-Nb diagram have been started, focussing on the Zr-rich corner, near the composition of Zirlo commercial alloy, Zr-1Sn-1Nb, and with Fe and O contents usual in nuclear grade materials. Three alloys were melted, namely Zr-4Sn-2.4Nb (A), Zr-1Sn-3Nb (B) and Zr-2.1Sn-1Nb (C). α/β transformation temperatures were measured through the variation of electrical resistivity(p) vs temperature (T). Values of 560 deg C, 670 deg C and 750 deg C were measured for the α→α+β reaction and 980 deg C, 910 deg C and 1000 deg C for the α+β→β reaction, for the A, B and C alloys, respectively in that order. Some samples were submitted to heat treatments (62 and 216 hours at 825 deg C, 120 hours at 875 deg C). Optical and scanning electronic microscopy of those samples confirmed our resistivity results. (Author)

Lead-free soldering: Investigation of the Cu-Sn-Sb system along the Sn:Sb = 1:1 isopleth

Energy Technology Data Exchange (ETDEWEB)

Yuan, Y. [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Borzone, G., E-mail: borzone@chimica.unige.it [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Zanicchi, G.; Delsante, S. [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy)

2011-02-03

Research highlights: > In the electronics industry, the solder alloys commonly used for assembly belong to the Sn-Pb system. Fulfilment of the EU RoHS (reduction of hazardous substances) requires the development of new lead-free alloys for applications in electronics, with the same or possibly better characteristics than the traditional Sn-Pb alloys. > This research concerns the investigation of the constitutional properties of the Cu-Sn-Sb system which is considered as lead-free replacement for high-temperature applications. - Abstract: The Cu-Sn-Sb system has been experimentally investigated by a combination of optical microscopy, differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). DSC was used to identify a total number of five invariant ternary reactions and the Sn:Sb = 1:1 isopleth section up to 65 at.% Cu was constructed by combining the DSC data with the EPMA analyses of annealed alloys and literature information. The composition limits of the binary phases were detected.

Structural and optical properties of Cu{sub 2}ZnSnS{sub 4} thin film absorbers from ZnS and Cu{sub 3}SnS{sub 4} nanoparticle precursors

Energy Technology Data Exchange (ETDEWEB)

Lin, Xianzhong, E-mail: lin.xianzhong@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Kavalakkatt, Jaison [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Berlin (Germany); Kornhuber, Kai; Levcenko, Sergiu [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Freie Universität Berlin, Berlin (Germany); Ennaoui, Ahmed, E-mail: ennaoui@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

2013-05-01

Cu{sub 2}ZnSnS{sub 4} (CZTS) has been considered as an alternative absorber layer to Cu(In,Ga)Se{sub 2} due to its earth abundant and environmentally friendly constituents, optimal direct band gap of 1.4–1.6 eV and high absorption coefficient in the visible range. In this work, we propose a solution-based chemical route for the preparation of CZTS thin film absorbers by spin coating of the precursor inks composed of Cu{sub 3}SnS{sub 4} and ZnS NPs and annealing in Ar/H{sub 2}S atmosphere. X-ray diffraction and Raman spectroscopy were used to characterize the structural properties. The chemical composition was determined by energy dispersive X-ray spectroscopy. Optical properties of the CZTS thin film absorbers were studied by transmission, reflection and photoluminescence spectroscopy.

Effect of Sn Composition in Ge1- x Sn x Layers Grown by Using Rapid Thermal Chemical Vapor Deposition

Science.gov (United States)

Kil, Yeon-Ho; Kang, Sukill; Jeong, Tae Soo; Shim, Kyu-Hwan; Kim, Dae-Jung; Choi, Yong-Dae; Kim, Mi Joung; Kim, Taek Sung

2018-05-01

The Ge1- x Sn x layers were grown by using rapid thermal chemical-vapor deposition (RTCVD) on boron-doped p-type Si (100) substrates with Sn compositions up to x = 0.83%. In order to obtain effect of the Sn composition on the structural and the optical characteristics, we utilized highresolution X-ray diffraction (HR-XRD), etch pit density (EPD), atomic force microscopy (AFM), Raman spectroscopy, and photocurrent (PC) spectra. The Sn compositions in the Ge1- x Sn x layers were found to be of x = 0.00%, 0.51%, 0.65%, and 0.83%. The root-mean-square (RMS) of the surface roughness of the Ge1- x Sn x layer increased from 2.02 nm to 3.40 nm as the Sn composition was increased from 0.51% to 0.83%, and EPD was on the order of 108 cm-2. The Raman spectra consist of only one strong peak near 300 cm-1, which is assigned to the Ge-Ge LO peaks and the Raman peaks shift to the wave number with increasing Sn composition. Photocurrent spectra show near energy band gap peaks and their peak energies decrease with increasing Sn composition due to band-gap bowing in the Ge1- x Sn x layer. An increase in the band gap bowing parameter was observed with increasing Sn composition.

A facile inexpensive route for SnS thin film solar cells with SnS{sub 2} buffer

Energy Technology Data Exchange (ETDEWEB)

Gedi, Sreedevi [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Minna Reddy, Vasudeva Reddy, E-mail: drmvasudr9@gmail.com [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Pejjai, Babu [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Jeon, Chan-Wook [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Park, Chinho, E-mail: chpark@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Ramakrishna Reddy, K.T., E-mail: ktrkreddy@gmail.com [Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India)

2016-05-30

Graphical abstract: PYS spectra of SnS/SnS{sub 2} interface and the related band diagram. - Highlights: • A low cost SnS solar cell is developed using chemical bath deposition. • We found E{sub I} & χ of SnS (5.3 eV & 4.0 eV) and SnS{sub 2} (6.9 eV & 4.1 eV) films from PYS. • Band offsets of 0.1 eV (E{sub c}) and 1.6 eV (E{sub v}) are estimated for SnS/SnS{sub 2} junction. • SnS based solar cell showed a conversion efficiency of 0.51%. - Abstract: Environment-friendly SnS based thin film solar cells with SnS{sub 2} as buffer layer were successfully fabricated from a facile inexpensive route, chemical bath deposition (CBD). Layer studies revealed that as-grown SnS and SnS{sub 2} films were polycrystalline; (1 1 1)/(0 0 1) peaks as the preferred orientation; 1.3 eV/2.8 eV as optical band gaps; and showed homogeneous microstructure with densely packed grains respectively. Ionization energy and electron affinity values were found by applying photoemission yield spectroscopy (PYS) to the CBD deposited SnS and SnS{sub 2} films for the first time. These values obtained as 5.3 eV and 4.0 eV for SnS films; 6.9 eV and 4.1 eV for SnS{sub 2} films. The band alignment of SnS/SnS{sub 2} junction showed TYPE-II heterostructure. The estimated conduction and valance band offsets were 0.1 eV and 1.6 eV respectively. The current density–voltage (J–V) measurements of the cell showed open circuit voltage (V{sub oc}) of 0.12 V, short circuit current density (J{sub sc}) of 10.87 mA cm{sup −2}, fill factor (FF) of 39% and conversion efficiency of 0.51%.

PbSnTe injection lasers

International Nuclear Information System (INIS)

Oron, M.

1982-03-01

Carrier confined homostructure PbSnTe lasers were developed and investigated. In this laser structure good electrical and optical confinement can be achieved by a suitable carrier concentration profile. The advantage of these lasers over PbSnTe heterostructure lasers is the perfect lattice matching between the various layers of the structure. The desired carrier concentration profile was achieved by the growth of several epitaxial layers by the LPE method on a suitable substrate. The performance of these lasers was compared with that of previous homostructure and double heterostructure lasers. (H.K.)

Phase diagram of the ternary Zr-Ti-Sn system

International Nuclear Information System (INIS)

Arias, D.; Gonzalez Camus, M.

1987-01-01

It is well known that Ti stabilizes the high temperature cubic phase of Zr and that Sn stabilizes the low temperature hexagonal phase of Zr. The effect of Sn on the Zr-Ti diagram has been studied in the present paper. Using high purity metals, nine different alloys have been prepared, with 4-32 at % Ti, 0.7-2.2 at % Sn and Zr till 100%. Resistivity and optical and SEM metallography techniques have been employed. Effect of some impurities have been analyzed. The results are discussed and different isothermic sections of the ternary Zr-Ti-Sn diagram are presented. (Author) [es

Different valence Sn doping - A simple way to detect oxygen concentration variation of ZnO quantum dots synthesized under ultrasonic irradiation.

Science.gov (United States)

Yang, Weimin; Zhang, Bing; Zhang, Qitu; Wang, Lixi; Song, Bo; Wu, Fan; Wong, C P

2017-09-01

An ultrasonic method is employed to synthesize the Sn doped Zn 0.95 Sn 0.05 O quantum dots with green light emission. Sn 2+ and Sn 4+ ions are used to create different optical defects inside Zn 0.95 Sn 0.05 O quantum dots and the changing trend of oxygen concentration under different ultrasonic irradiation power are investigated. The photoluminescence spectra are employed to characterize the optical defects of Zn 0.95 Sn 0.05 O quantum dots. The UV-vis spectra are used to study the band gap of Zn 0.95 Sn 0.05 O quantum dots, which is influenced by their sizes. The results indicate that ultrasonic power would influence the size of Zn 0.95 Sn 0.05 O quantum dots as well as the type and quantity of defects in ZnO quantum dots. Changing trends in size of Sn 2+ and Sn 4+ doped Zn 0.95 Sn 0.05 O quantum dots are quite similar with each other, while the changing trends in optical defects types and concentration of Sn 2+ and Sn 4+ doped Zn 0.95 Sn 0.05 O quantum dots are different. The difference of the optical defects concentration changing between Sn 2+ doped Zn 0.95 Sn 0.05 O quantum dots (V O defects) and Sn 4+ doped Zn 0.95 Sn 0.05 O quantum dots (O Zn and O i defects) shows that the formation process of ZnO under ultrasonic irradiation wiped oxygen out. Copyright © 2017 Elsevier B.V. All rights reserved.

Optical properties and surface characterization of pulsed laser-deposited Cu2ZnSnS4 by spectroscopic ellipsometry

International Nuclear Information System (INIS)

Crovetto, Andrea; Cazzaniga, Andrea; Ettlinger, Rebecca B.; Schou, Jørgen; Hansen, Ole

2015-01-01

Cu 2 ZnSnS 4 films prepared by pulsed laser deposition at different temperatures are characterized by spectroscopic ellipsometry. The focus is on confirming results from direct measurement techniques, by finding appropriate models of the surface overlayer for data fitting, and extracting the dielectric function of the films. It is found that the surface overlayer changes with film thickness and deposition temperature. Adopting different ellipsometry measurements and modeling strategies for each film, dielectric functions are extracted and compared. As the deposition temperature is increased, the dielectric functions exhibit additional critical points related to optical transitions in the material other than absorption across the fundamental band gap. In the case of a thin film < 200 nm thick, surface features observed by scanning electron microscopy and atomic force microscopy are accurately reproduced by ellipsometry data fitting. - Highlights: • Inhomogeneous Cu 2 ZnSnS 4 films are prepared by pulsed laser deposition. • The film surface includes secondary phases and topographic structures. • We model a film surface layer that fits ellipsometry data. • Ellipsometry data fits confirm results from direct measurement techniques. • We obtain the dielectric function of inhomogeneous Cu 2 ZnSnS 4 films

Fabrication of high crystalline SnS and SnS2 thin films, and their switching device characteristics

Science.gov (United States)

Choi, Hyeongsu; Lee, Jeongsu; Shin, Seokyoon; Lee, Juhyun; Lee, Seungjin; Park, Hyunwoo; Kwon, Sejin; Lee, Namgue; Bang, Minwook; Lee, Seung-Beck; Jeon, Hyeongtag

2018-05-01

Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS2) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS2 thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS2 thin film by annealing at 450 °C for 1 h in H2S atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS2 thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 105 and 104 cm‑1 in the visible region, respectively. In addition, SnS and SnS2 thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS2 directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS2 thin films exhibited on–off drain current ratios of 8.8 and 2.1 × 103 and mobilities of 0.21 and 0.014 cm2 V‑1 s‑1, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS2 thin films were 6.0 × 1016 and 8.7 × 1013 cm‑3, respectively, in this experiment.

Exploring single-layered SnSe honeycomb polymorphs for optoelectronic and photovoltaic applications

Science.gov (United States)

Ul Haq, Bakhtiar; AlFaify, S.; Ahmed, R.; Butt, Faheem K.; Laref, A.; Shkir, Mohd.

2018-02-01

Single-layered tin selenide that shares the same structure with phosphorene and possesses intriguing optoelectronic properties has received great interest as a two-dimensional material beyond graphene and phosphorene. Herein, we explore the optoelectronic response of the newly discovered stable honeycomb derivatives (such as α , β , γ , δ , and ɛ ) of single-layered SnSe in the framework of density functional theory. The α , β , γ , and δ derivatives of a SnSe monolayer have been found to exhibit an indirect band gap, however, the dispersion of their band-gap edges demonstrates multiple direct band gaps at a relatively high energy. The ɛ -SnSe, however, features an intrinsic direct band gap at the high-symmetry Γ point. Their energy band gaps (0.53, 2.32, 1.52, 1.56, and 1.76 eV for α -, β -, γ -, δ -, and ɛ -SnSe, respectively), calculated at the level of the Tran-Blaha modified Becke-Johnson approach, mostly fall right in the visible range of the electromagnetic spectrum and are in good agreement with the available literature. The optical spectra of these two-dimensional (2D) SnSe polymorphs (besides β -SnSe) are highly anisotropic and possess strictly different optical band gaps along independent diagonal components. They show high absorption in the visible and UV ranges. Similarly, the reflectivity, refraction, and optical conductivities inherit strong anisotropy from the dielectric functions as well and are highly visible-UV polarized along the cartesian coordinates, showing them to be suitable for optical filters, polarizers, and shields against UV radiation. Our investigations suggest these single-layered SnSe allotropes as a promising 2D material for next-generation nanoscale optoelectronic and photovoltaic applications beyond graphene and phosphorene.

Characterization and Optical Properties of the Single Crystalline SnS Nanowire Arrays

Directory of Open Access Journals (Sweden)

Yue GH

2009-01-01

Full Text Available Abstract The SnS nanowire arrays have been successfully synthesized by the template-assisted pulsed electrochemical deposition in the porous anodized aluminum oxide template. The investigation results showed that the as-synthesized nanowires are single crystalline structures and they have a highly preferential orientation. The ordered SnS nanowire arrays are uniform with a diameter of 50 nm and a length up to several tens of micrometers. The synthesized SnS nanowires exhibit strong absorption in visible and near-infrared spectral region and the direct energy gapE gof SnS nanowires is 1.59 eV.

Interfacial Interactions in Monolayer and Few-Layer SnS/CH3 NH3 PbI3 Perovskite van der Waals Heterostructures and Their Effects on Electronic and Optical Properties.

Science.gov (United States)

Li, Jian-Cai; Wei, Zeng-Xi; Huang, Wei-Qing; Ma, Li-Li; Hu, Wangyu; Peng, Ping; Huang, Gui-Fang

2018-02-05

A high light-absorption coefficient and long-range hot-carrier transport of hybrid organic-inorganic perovskites give huge potential to their composites in solar energy conversion and environmental protection. Understanding interfacial interactions and their effects are paramount for designing perovskite-based heterostructures with desirable properties. Herein, we systematically investigated the interfacial interactions in monolayer and few-layer SnS/CH 3 NH 3 PbI 3 heterostructures and their effects on the electronic and optical properties of these structures by density functional theory. It was found that the interfacial interactions in SnS/CH 3 NH 3 PbI 3 heterostructures were van der Waals (vdW) interactions, and they were found to be insensitive to the layer number of 2D SnS sheets. Interestingly, although their band gap decreased upon increasing the layer number of SnS, the near-gap electronic states and optical absorption spectra of these heterostructures were found to be strikingly similar. This feature was determined to be critical for the design of 2D layered SnS-based heterostructures. Strong absorption in the ultraviolet and visible-light regions, type II staggered band alignment at the interface, and few-layer SnS as an active co-catalyst make 2D SnS/CH 3 NH 3 PbI 3 heterostructures promising candidates for photocatalysis, photodetectors, and solar energy harvesting and conversion. These results provide first insight into the nature of interfacial interactions and are useful for designing hybrid organic-inorganic perovskite-based devices with novel properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-layer ZnMN2 (M = Si, Ge, Sn) zinc nitrides as promising photocatalysts.

Science.gov (United States)

Bai, Yujie; Luo, Gaixia; Meng, Lijuan; Zhang, Qinfang; Xu, Ning; Zhang, Haiyang; Wu, Xiuqiang; Kong, Fanjie; Wang, Baolin

2018-05-30

Searching for two-dimensional semiconductor materials that are suitable for visible-light photocatalytic water splitting provides a sustainable solution to deal with the future energy crisis and environmental problems. Herein, based on first-principles calculations, single-layer ZnMN2 (M = Si, Ge, Sn) zinc nitrides are proposed as efficient photocatalysts for water splitting. Stability analyses show that the single-layer ZnMN2 zinc nitrides exhibit energetic and dynamical stability. The electronic properties reveal that all of the single-layer ZnMN2 zinc nitrides are semiconductors. Interestingly, single-layer ZnSnN2 is a direct band gap semiconductor with a desirable band gap (1.74 eV), and the optical adsorption spectrum confirms its optical absorption in the visible light region. The hydrogen evolution reaction (HER) calculations show that the catalytic activity for single-layer ZnMN2 (M = Ge, Sn) is better than that of single-layer ZnSiN2. Furthermore, the band gaps and band edge positions for the single-layer ZnMN2 zinc nitrides can be effectively tuned by biaxial strain. Especially, single-layer ZnGeN2 can be effectively tuned to match better with the redox potentials of water and enhance the light absorption in the visible light region at a tensile strain of 5%, which is confirmed by the corresponding optical absorption spectrum. Our results provide guidance for experimental synthesis efforts and future searches for single-layer materials suitable for photocatalytic water splitting.

THE 2012 RISE OF THE REMARKABLE TYPE IIn SN 2009ip

International Nuclear Information System (INIS)

Prieto, José L.; Brimacombe, J.; Drake, A. J.; Howerton, S.

2013-01-01

Recent observations by Mauerhan et al. have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova (SN) impostor SN 2009ip to a real Type IIn SN explosion. We present ∼100 optical R- and I-band photometric measurements of SN 2009ip obtained between UT 2012 September 23.6 and October 9.6, using 0.3-0.4 m aperture telescopes from the Coral Towers Observatory in Cairns, Australia. The light curves show well-defined phases, including very rapid brightening early on (0.5 mag in 6 hr observed during the night of September 24), a transition to a much slower rise between September 25 and September 28, and a plateau/peak around October 7. These changes are coincident with the reported spectroscopic changes that most likely mark the start of a strong interaction between the fast SN ejecta and a dense circumstellar medium formed during the LBV eruptions observed in recent years. In the 16-day observing period, SN 2009ip brightened by 3.7 mag from I = 17.4 mag on September 23.6 (M I ≅ –14.2) to I = 13.7 mag (M I ≅ –17.9) on October 9.6, radiating ∼3 × 10 49 erg in the optical wavelength range. As of 2012 October 9.6, SN 2009ip is more luminous than most Type IIP SN and comparable to other Type IIn SN.

SnSAG5 is an alternative surface antigen of Sarcocystis neurona strains that is mutually exclusive to SnSAG1.

Science.gov (United States)

Crowdus, Carolyn A; Marsh, Antoinette E; Saville, Willliam J; Lindsay, David S; Dubey, J P; Granstrom, David E; Howe, Daniel K

2008-11-25

Sarcocystis neurona is an obligate intracellular parasite that causes equine protozoal myeloencephalitis (EPM). Previous work has identified a gene family of paralogous surface antigens in S. neurona called SnSAGs. These surface proteins are immunogenic in their host animals, and are therefore candidate molecules for development of diagnostics and vaccines. However, SnSAG diversity exists in strains of S. neurona, including the absence of the major surface antigen gene SnSAG1. Instead, sequence for an alternative SnSAG has been revealed in two of the SnSAG1-deficient strains. Herein, we present data characterizing this new surface protein, which we have designated SnSAG5. The results indicated that the protein encoded by the SnSAG5 sequence is indeed a surface-associated molecule that has characteristics consistent with the other SAGs identified in S. neurona and related parasites. Importantly, Western blot analyses of a collection of S. neurona strains demonstrated that 6 of 13 parasite isolates express SnSAG5 as a dominant surface protein instead of SnSAG1. Conversely, SnSAG5 was not detected in SnSAG1-positive strains. One strain, which was isolated from the brain of a sea otter, did not express either SnSAG1 or SnSAG5. Genetic analysis with SnSAG5-specific primers confirmed the presence of the SnSAG5 gene in Western blot-positive strains, while also suggesting the presence of a novel SnSAG sequence in the SnSAG1-deficient, SnSAG5-deficient otter isolate. The findings provide further indication of S. neurona strain diversity, which has implications for diagnostic testing and development of vaccines against EPM as well as the population biology of Sarcocystis cycling in the opossum definitive host.

SnO{sub 2}:F thin films deposited by RF magnetron sputtering: effect of the SnF{sub 2} amount in the target on the physical properties

Energy Technology Data Exchange (ETDEWEB)

De Moure F, F. [universidad Autonoma de Queretaro, Facultad de Quimica Materiales, Queretaro 76010, Queretaro (Mexico); Guillen C, A.; Nieto Z, K. E.; Quinones G, J. G.; Hernandez H, A.; Melendez L, M.; Olvera, M. de la L., E-mail: fcomoure@hotmail.com [IPN, Centro de Investigacion y de Estudios Avanzados, Departamento de Fisica, Apdo. Postal 14-740, 07360 Mexico D. F. (Mexico)

2013-08-01

SnO{sub 2}:F thin films were prepared by RF magnetron sputtering onto glass substrates using SnF{sub 2} as fluorine source. The films were deposited under a mixed argon/hydrogen atmosphere at a substrate temperature of 500 C. The X-ray diffraction shows that polycrystalline films were grown with a phases mixture of SnO{sub 2} and Sn O. The optical transmittance is between 80 and 90%. The physical properties of the films suggest that SnO{sub 2} thin films grown with small SnF{sub 2} content in the target can be considered as candidates for transparent electrodes. (Author)

Composition dependence of structural and optical properties in epitaxial Sr(Sn1-xTix)O3 films

Science.gov (United States)

Liu, Qinzhuang; Li, Bing; Li, Hong; Dai, Kai; Zhu, Guangping; Wang, Wei; Zhang, Yongxing; Gao, Guanyin; Dai, Jianming

2015-03-01

Epitaxial Sr(Sn1-xTix)O3 (SSTO, x = 0-1) thin films were grown on MgO substrates by a pulsed laser deposition technique. The effects of composition on the structural and optical properties of SSTO films were investigated. X-ray diffraction studies show that the lattice parameter decreases from 4.041 to 3.919 Å gradually with increasing Ti content from 0 to 1 in SSTO films. Optical spectra analysis reveals that the band gap energy Eg decreases continuously from 4.44 to 3.78 eV over the entire doping range, which is explained by the decreasing degree of octahedral tilting distortion and thus the increasing tolerance factor caused by the increasing small-Ti-ion doping concentration.

Fabrication and optical properties of SnS thin films by SILAR method

International Nuclear Information System (INIS)

Ghosh, Biswajit; Das, Madhumita; Banerjee, Pushan; Das, Subrata

2008-01-01

Although the fabrication of tin disulfide thin films by SILAR method is quiet common, there is, however, no report is available on the growth of SnS thin film using above technique. In the present work, SnS films of 0.20 μm thickness were grown on glass and ITO substrates by SILAR method using SnSO 4 and Na 2 S solution. The as-grown films were smooth and strongly adherent to the substrate. XRD confirmed the deposition of SnS thin films. Scanning electron micrograph revealed almost equal distribution of the particle size well covered on the surface of the substrate. EDAX showed that as-grown SnS films were slightly rich in tin component while UV-vis transmission spectra exhibited high absorption in the visible region. The intense and sharp emission peaks at 680 and 825 nm (near band edge emission) dominated the photoluminescence spectra

Effect of thermal annealing on the structural and optical properties of Cu2FeSnS4 thin films grown by vacuum evaporation method

Science.gov (United States)

Oueslati, H.; Rabeh, M. Ben; Kanzari, M.

2018-02-01

In this work, the effect of different types of thermal annealing on the properties of Cu2FeSnS4 (CFTS) thin films deposited by thermal evaporation at room temperature on glass substrate were investigated. CFTS powder was synthesized by direct melting of the constituent elements taken in stoichiometry compositions. The X-ray diffraction experimental data indicating that the Cu2FeSnS4 powder illustrating a stannite structure in space group I\\bar {4}2m. From the XRD analysis we have found that the polycrystalline CFTS thin film was only obtained by thermal annealed in sulfur atmosphere under a high vacuum of 400 °C temperature during 2 h. Optical study reveals that the thin films have relatively high absorption coefficients (≈ 105cm-1) and the values of optical band gap energy ranged between 1.38 and 1.48 eV. Other optical parameters were evaluated according to the models of Wemple Di-Domenico and Spitzer-Fan. Finally, hot probe measurements of CFTS thin films reveal p-type conductivity.

Effect of solvent on the synthesis of SnO_2 nanoparticles

International Nuclear Information System (INIS)

Kumar, Virender; Singh, Karamjit; Singh, Kulwinder; Kumar, Akshay; Kumari, Sudesh; Thakur, Anup

2016-01-01

Tin oxide (SnO_2) nanoparticles have been synthesized by co-precipitation method. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD) and Ultraviolet-Visible spectroscopy (UV-VIS). XRD analysis confirmed the formation of single phase of SnO_2 nanoparticles. It has been found that solvents played important role in controlling the crystallite size of SnO_2 nanoparticles. The XRD analysis showed well crystallized tetragonal SnO_2 nanoparticles. The crystallite size of SnO_2 nanoparticles varies with the solvent. Tauc plot showed that optical band gap was also tailored by controlling the solvent during synthesis.

Controlling the antibacterial activity of CuSn thin films by varying the contents of Sn

Energy Technology Data Exchange (ETDEWEB)

Kang, Yujin; Park, Juyun; Kim, Dong-Woo; Kim, Hakjun; Kang, Yong-Cheol, E-mail: yckang@pknu.ac.kr

2016-12-15

Highlights: • We deposit CuSn thin films on a Si substrate with various Cu/Sn ratio. • Antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time increased. • XPS was utilized to assign the chemical environment of CuSn thin films before and after antibacterial test. - Abstract: We investigated antibacterial activity of CuSn thin films against Gram positive Staphylococcus aureus (S. aureus). CuSn thin films with different Cu to Sn ratios were deposited on Si(100) by radio frequency (RF) magnetron sputtering method using Cu and Sn metal anodes. The film thickness was fixed at 200 nm by varying the sputtering time and RF power on the metal targets. The antibacterial test was conducted in various conditions such as different contact times and Cu to Sn ratios in the CuSn films. The antibacterial activities of CuSn thin films increased as the ratio of Cu and the contact time between the film and bacteria suspension increased execpt in the case of CuSn-83. The oxidation states of Cu and Sn and the chemical composition of CuSn thin films before and after the antibacterial test were investigated by X-ray photoelectron spectroscopy (XPS). When the contact time was fixed, the Cu species was further oxidized as the RF power on Cu target increased. The intensity of Sn 3d decreased with increasing Cu ratio. When the sample was fixed, the peak intensity of Sn 3d decreased as the contact time increased due to the permeation of Sn into the cell.

Fabrication of p-type conductivity in SnO{sub 2} thin films through Ga doping

Energy Technology Data Exchange (ETDEWEB)

Tsay, Chien-Yie, E-mail: cytsay@fcu.edu.tw; Liang, Shan-Chien

2015-02-15

Highlights: • P-type Ga-doped SnO{sub 2} semiconductor films were prepared by sol-gel spin coating. • Optical bandgaps of the SnO{sub 2}:Ga films are narrower than that of the SnO{sub 2} film. • SnO{sub 2}:Ga films exhibited p-type conductivity as Ga doping content higher than 10%. • A p-n heterojunction composed of p-type SnO{sub 2}:Ga and n-type ZnO:Al was fabricated. - Abstract: P-type transparent tin oxide (SnO{sub 2}) based semiconductor thin films were deposited onto alkali-free glass substrates by a sol-gel spin-coating method using gallium (Ga) as acceptor dopant. In this study, we investigated the influence of Ga doping concentration ([Ga]/[Sn] + [Ga] = 0%, 5%, 10%, 15%, and 20%) on the structural, optical and electrical properties of SnO{sub 2} thin films. XRD analysis results showed that dried Ga-doped SnO{sub 2} (SnO{sub 2}:Ga) sol-gel films annealed in oxygen ambient at 520 °C for 1 h exhibited only the tetragonal rutile phase. The average optical transmittance of as-prepared thin film samples was higher than 87.0% in the visible light region; the optical band gap energy slightly decreased from 3.92 eV to 3.83 eV with increases in Ga doping content. Hall effect measurement showed that the nature of conductivity of SnO{sub 2}:Ga thin films changed from n-type to p-type when the Ga doping level was 10%, and when it was at 15%, Ga-doped SnO{sub 2} thin films exhibited the highest mean hole concentration of 1.70 × 10{sup 18} cm{sup -3}. Furthermore, a transparent p-SnO{sub 2}:Ga (Ga doping level of 15%)/n-ZnO:Al (Al doping level of 2%) heterojunction was fabricated on alkali-free glass. The I-V curve measurement for the p-n heterojunction diode showed a typical rectifying characteristic with a forward turn-on voltage of 0.65 V.

Determination of positions of optical elements of the human eye

International Nuclear Information System (INIS)

Galetskii, S O; Cherezova, T Yu

2009-01-01

An original method for noninvasive determining the positions of elements of intraocular optics is proposed. The analytic dependence of the measurement error on the optical-scheme parameters and the restriction in distance from the element being measured are determined within the framework of the method proposed. It is shown that the method can be efficiently used for determining the position of elements in the classical Gullstrand eye model and personalised eye models. The positions of six optical surfaces of the Gullstrand eye model and four optical surfaces of the personalised eye model can be determined with an error of less than 0.25 mm. (human eye optics)

Nanocrystalline SnO2 thin films: Structural, morphological, electrical transport and optical studies

International Nuclear Information System (INIS)

Sakhare, R.D.; Khuspe, G.D.; Navale, S.T.; Mulik, R.N.; Chougule, M.A.; Pawar, R.C.; Lee, C.S.; Sen, Shashwati; Patil, V.B.

2013-01-01

Highlights: ► Novel chemical route of synthesis of SnO 2 films. ► Physical properties SnO 2 are influenced by process temperature. ► The room temperature electrical conductivity of SnO 2 is of 10 −7 –10 −5 (Ω cm) −1 . ► SnO 2 exhibit high absorption coefficient (10 4 cm −1 ). -- Abstract: Sol–gel spin coating method has been successfully employed for preparation of nanocrystalline tin oxide (SnO 2 ) thin films. The effect of processing temperature on the structure, morphology, electrical conductivity, thermoelectric power and band gap was studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction pattern, atomic force microscopy, two probe technique and UV–visible spectroscopy. X-ray diffraction (XRD) analysis showed that SnO 2 films are crystallized in the tetragonal phase and present a random orientation. Field emission scanning electron microscopy (FESEM) analysis revealed that surface morphology of the tin oxide film consists nanocrystalline grains with uniform coverage of the substrate surface. Transmission electron microscopy (TEM) of SnO 2 film showed nanocrystals having diameter ranging from 5 to 10 nm. Selected area electron diffraction (SAED) pattern confirms tetragonal phase evolution of SnO 2 . Atomic force microscopy (AFM) analysis showed surface morphology of SnO 2 film is smooth. The dc electrical conductivity showed the semiconducting nature with room temperature electrical conductivity increased from 10 −7 to 10 −5 (Ω cm) −1 as processing temperature increased from 400 to 700 °C. Thermo power measurement confirms n-type conduction. The band gap energy of SnO 2 film decreased from 3.88 to 3.60 eV as processing temperature increased from 400 to 700 °C

P-type SnO thin films and SnO/ZnO heterostructures for all-oxide electronic and optoelectronic device applications

Energy Technology Data Exchange (ETDEWEB)

Saji, Kachirayil J. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Govt. Victoria College, University of Calicut, Palakkad 678 001 (India); Venkata Subbaiah, Y.P. [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Department of Physics, Yogi Vemana University, Kadapa, Andhra Pradesh 516003 (India); Tian, Kun [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu [Nanostructured Materials Research Laboratory, Department of Materials Science & Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

2016-04-30

Tin monoxide (SnO) is considered as one of the most important p-type oxides available to date. Thin films of SnO have been reported to possess both an indirect bandgap (~ 0.7 eV) and a direct bandgap (~ 2.8 eV) with quite high hole mobility (~ 7 cm{sup 2}/Vs) values. Moreover, the hole density in these films can be tuned from 10{sup 15}–10{sup 19} cm{sup −3} just by controlling the thin film deposition parameters. Because of the above attributes, SnO thin films offer great potential for fabricating modern electronic and optoelectronic devices. In this article, we are reviewing the most recent developments in this field and also presenting some of our own results on SnO thin films grown by pulsed laser deposition technique. We have also proposed a p–n heterostructure comprising of p-type SnO and n-type ZnO which can pave way for realizing next-generation, all-oxide transparent electronic devices. - Highlights: • We reviewed recent developments on p-type SnO thin film research. • Discussed the optical and electrical properties of SnO thin films • Bipolar conduction in SnO is discussed. • Optoelectronic properties of SnO–ZnO composite system are discussed. • Proposed SnO–ZnO heterojunction band structure.

Structure, Surface Morphology, and Optical and Electronic Properties of Annealed SnS Thin Films Obtained by CBD

Science.gov (United States)

Reghima, Meriem; Akkari, Anis; Guasch, Cathy; Turki-Kamoun, Najoua

2014-09-01

SnS thin films were initially coated onto Pyrex substrates by the chemical bath deposition (CBD) method and annealed at various temperatures ranging from 200°C to 600°C for 30 min in nitrogen gas. X-ray diffraction (XRD) analysis revealed that a structural transition from face-centered cubic to orthorhombic occurs when the annealing temperature is over 500°C. The surface morphology of all thin layers was investigated by means of scanning electron microscopy and atomic force microscopy. The elemental composition of Sn and S, as measured by energy dispersive spectroscopy, is near the stoichiometric ratio. Optical properties studied by means of transmission and reflection measurements show an increase in the absorption coefficient with increasing annealing temperatures. The band gap energy is close to 1.5 eV, which corresponds to the optimum for photovoltaic applications. Last, the thermally stimulated current measurements show that the electrically active traps located in the band gap disappear after annealing at 500°C. These results suggest that, once again, annealing as a post-deposition treatment may be useful for improving the physical properties of the SnS layers included in photovoltaic applications. Moreover, the thermo-stimulated current method may be of practical relevance to explore the electronic properties of more conventional industrial methods, such as sputtering and chemical vapor deposition.

Side-emitting fiber optic position sensor

Science.gov (United States)

Weiss, Jonathan D [Albuquerque, NM

2008-02-12

A side-emitting fiber optic position sensor and method of determining an unknown position of an object by using the sensor. In one embodiment, a concentrated beam of light source illuminates the side of a side-emitting fiber optic at an unknown axial position along the fiber's length. Some of this side-illuminated light is in-scattered into the fiber and captured. As the captured light is guided down the fiber, its intensity decreases due to loss from side-emission away from the fiber and from bulk absorption within the fiber. By measuring the intensity of light emitted from one (or both) ends of the fiber with a photodetector(s), the axial position of the light source is determined by comparing the photodetector's signal to a calibrated response curve, look-up table, or by using a mathematical model. Alternatively, the side-emitting fiber is illuminated at one end, while a photodetector measures the intensity of light emitted from the side of the fiber, at an unknown position. As the photodetector moves further away from the illuminated end, the detector's signal strength decreases due to loss from side-emission and/or bulk absorption. As before, the detector's signal is correlated to a unique position along the fiber.

A Rapid Method for Deposition of Sn-Doped GaN Thin Films on Glass and Polyethylene Terephthalate Substrates

Science.gov (United States)

Pat, Suat; Özen, Soner; Korkmaz, Şadan

2018-01-01

We report the influence of Sn doping on microstructure, surface, and optical properties of GaN thin films deposited on glass and polyethylene terephthalate (PET) substrate. Sn-doped GaN thin films have been deposited by thermionic vacuum arc (TVA) at low temperature. TVA is a rapid deposition technology for thin film growth. Surface and optical properties of the thin films were presented. Grain size, height distribution, roughness values were determined. Grain sizes were calculated as 20 nm and 13 nm for glass and PET substrates, respectively. Nano crystalline forms were shown by field emission scanning electron microscopy. Optical band gap values were determined by optical methods and photoluminescence measurement. The optical band gap values of Sn doped GaN on glass and PET were determined to be approximately ˜3.40 eV and ˜3.47 eV, respectively. As a result, TVA is a rapid and low temperature deposition technology for the Sn doped GaN deposited on glass and PET substrate.

Fluorescent optical position sensor

Science.gov (United States)

Weiss, Jonathan D.

2005-11-15

A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys; Efeitos da adicao de Sn na evolucao microestrutural e em propriedades mecanicas de ligas Ti-Nb-Sn biomedicas fundidas por centrifugacao

Energy Technology Data Exchange (ETDEWEB)

Lopes, E.S.N.; Contieri, R.J.; Caram, R., E-mail: ederlopes@fem.unicamp.b [Universidade Estadual de Campinas (DEMA/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais; Moraes, P.E.L. [FATEC Artur Azevedo, Mogi Mirim, SP (Brazil); Costa, A.M.S. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materiais

2010-07-01

The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

Whisker and Hillock formation on Sn, Sn-Cu and Sn-Pb electrodeposits

International Nuclear Information System (INIS)

Boettinger, W.J.; Johnson, C.E.; Bendersky, L.A.; Moon, K.-W.; Williams, M.E.; Stafford, G.R.

2005-01-01

High purity bright Sn, Sn-Cu and Sn-Pb layers, 3, 7 and 16 μm thick were electrodeposited on phosphor bronze cantilever beams in a rotating disk apparatus. Beam deflection measurements within 15 min of plating proved that all electrodeposits had in-plane compressive stress. In several days, the surfaces of the Sn-Cu deposits, which have the highest compressive stress, develop 50 μm contorted hillocks and 200 μm whiskers, pure Sn deposits develop 20 μm compact conical hillocks, and Sn-Pb deposits, which have the lowest compressive stress, remain unchanged. The differences between the initial compressive stresses for each alloy and pure Sn is due to the rapid precipitation of Cu 6 Sn 5 or Pb particles, respectively, within supersaturated Sn grains produced by electrodeposition. Over longer time, analysis of beam deflection measurements indicates that the compressive stress is augmented by the formation of Cu 6 Sn 5 on the bronze/Sn interface, while creep of the electrodeposit tends to decrease the compressive stress. Uniform creep occurs for Sn-Pb because it has an equi-axed grain structure. Localized creep in the form of hillocks and whiskers occurs for Sn and Sn-Cu because both have columnar structures. Compact hillocks form for the Sn deposits because the columnar grain boundaries are mobile. Contorted hillocks and whiskers form for the Sn-Cu deposits because the columnar grain boundary motion is impeded

Effects of sulfurization on the optical properties of Cu2ZnxFe1-xSnS4 thin films

Science.gov (United States)

Hannachi, A.; Oueslati, H.; Khemiri, N.; Kanzari, M.

2017-10-01

In order to prepare thin films of novel semiconductor materials that contain only earth abundant, low cost and nontoxic elements, Cu2ZnxFe1-xSnS4 ingots were successfully synthesized by direct fusion method. Crushed powders of these ingots were used as raw materials for the thermal evaporation. Cu2ZnxFe1-xSnS4 (with x = 0, 0.25, 0.5, 0.75 and 1) thin films were deposited on non-heated glass substrates by vacuum evaporation method. The as deposited films were sulfurized for 30 min at sulfurization temperature Ts = 400 °C. The effects of the sulfurization on the structural and optical properties of CZFTS films were realized by X-ray diffraction (XRD) and UV-Vis spectroscopy. XRD patterns show that all sulfurized CZFTS films were polycrystalline in nature with a preferential orientation along the (112) plane. CFTS films exhibit a stannite structure while CZTS films had a kesterite structure. Optical measurements showed that CZFTS films sulfurized at 400 °C exhibited an optical transmittance between 60 and 80% and all materials had relatively high absorption coefficients in the range of 104-105 cm-1. The band gap energies of sulfurized CZFTS films decreased from 1.71 to 1.50 eV with the increase of the Zn content. The dispersion of the refractive index was discussed in terms of the single oscillator model proposed by Wemple and DiDomenico and the optical parameters such as refractive index, extinction coefficient, oscillator energy and dispersion energy were calculated. The electrical free carrier susceptibility and the carrier concentration on the effective mass ratio were evaluated according to the model of Spitzer and Fan. The hot probe analysis showed that all sulfurized CZFTS films are p-type conductivity.

Electrochemical synthesis of nanostructured Se-doped SnS: Effect of Se-dopant on surface characterizations

International Nuclear Information System (INIS)

Kafashan, Hosein; Azizieh, Mahdi; Balak, Zohre

2017-01-01

Highlights: • Nanostructured SnS_1_-_xSe_x thin films were prepared by using electrodeposition method. • The XRD patterns obviously showed that the synthesized films were polycrystalline. • The PL spectra of SnS_1_-_xSe_x thin films showed four emission peaks. • The UV–vis spectra shows a variation in the optical band gap energy of SnS_1_-_xSe_x thin films from 1.22 to 1.65 eV. • SnS_1_-_xSe_x thin films would be suitable for use as absorber layers. - Abstract: SnS_1_-_xSe_x nanostructures with different Se-dopant concentrations were deposited on fluorine doped tin oxide (FTO) substrate through cathodic electrodeposition technique. The pH, temperature, applied potential (E), and deposition time remained were 2.1, 60 °C, −1 V, and 30 min, respectively. SnS_1_-_xSe_x nanostructures were characterized using X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), energy dispersive X-ray spectroscopy (EDX), room temperature photoluminescence (PL), and UV–vis spectroscopy. The XRD patterns revealed that the SnS_1_-_xSe_x nanostructures were polycrystalline with orthorhombic structure. FESEM showed various kinds of morphologies in SnS_1_-_xSe_x nanostructures due to Se-doping. PL and UV–vis spectroscopy were used to evaluate the optical properties of SnS_1_-_xSe_x thin films. The PL spectra of SnS_1_-_xSe_x nanostructures displayed four emission peaks, those are a blue, a green, an orange, and a red emission. UV–vis spectra showed that the optical band gap energy (E_g) of SnS_1_-_xSe_x nanostructures varied between 1.22–1.65 eV, due to Se-doping.

Effect of Zn/Sn molar ratio on the microstructural and optical properties of Cu2Zn1-xSnxS4 thin films prepared by spray pyrolysis technique

Science.gov (United States)

Thiruvenkadam, S.; Prabhakaran, S.; Sujay Chakravarty; Ganesan, V.; Vasant Sathe; Santhosh Kumar, M. C.; Leo Rajesh, A.

2018-03-01

Quaternary kesterite Cu2ZnSnS4 (CZTS) compound is one of the most promising semiconductor materials consisting of abundant and eco-friendly elements for absorption layer in thin film solar cells. The effect of Zn/Sn ratio on Cu2Zn1-xSnxS4 (0 ≤ x ≤ 1) thin films were studied by deposited by varying molar volumes in the precursor solution of zinc and tin was carried out in proportion of (1-x) and x respectively onto soda lime glass substrates kept at 573 K by using chemical spray pyrolysis technique. The GIXRD pattern revealed that the films having composites of Cu2ZnSnS4, Cu2SnS3, Sn2S3, CuS and ZnS phases. The crystallinity and grain size were found to increase by increasing the x value and the preferential orientation along (103), (112), (108) and (111) direction corresponding to CZTS, Cu2SnS3, CuS, and ZnS phases respectively. Micro-Raman spectra exposed a prominent peak at 332 cm-1 corresponding to the CZTS phase. Atomic force microscopy was employed to study the grain size and roughness of the deposited thin films. The optical band gap was found to lie between 1.45 and 2.25 eV and average optical absorption coefficient was found to be greater than 105 cm-1. Hall measurements exhibited that all the deposited Cu2Zn1-xSnxS4 films were p type and the resistivity lies between 10.9 ×10-2Ωcm and 149.6 × 10-2Ωcm .

SN 2008iy: An Unusual Type IIn Supernova with an Enduring 400 Day Rise Time

OpenAIRE

Miller, A. A.; Silverman, J. M.; Butler, N. R.; Bloom, J. S.; Chornock, R.; Filippenko, A. V.; Ganeshalingam, M.; Klein, C. R.; Li, W.; Nugent, P. E.; Smith, N.; Steele, T. N.

2009-01-01

We present spectroscopic and photometric observations of the Type IIn supernova (SN) 2008iy. SN 2008iy showed an unprecedentedly long rise time of ~400 days, making it the first SN to take significantly longer than 100 days to reach peak optical luminosity. The peak absolute magnitude of SN 2008iy was M_r ~ -19.1 mag, and the total radiated energy over the first ~700 days was ~2 x 10^50 erg. Spectroscopically, SN 2008iy is very similar to the Type IIn SN 1988Z at late times, and, like SN 1988...

The 7SK snRNP associates with the little elongation complex to promote snRNA gene expression.

Science.gov (United States)

Egloff, Sylvain; Vitali, Patrice; Tellier, Michael; Raffel, Raoul; Murphy, Shona; Kiss, Tamás

2017-04-03

The 7SK small nuclear RNP (snRNP), composed of the 7SK small nuclear RNA (snRNA), MePCE, and Larp7, regulates the mRNA elongation capacity of RNA polymerase II (RNAPII) through controlling the nuclear activity of positive transcription elongation factor b (P-TEFb). Here, we demonstrate that the human 7SK snRNP also functions as a canonical transcription factor that, in collaboration with the little elongation complex (LEC) comprising ELL, Ice1, Ice2, and ZC3H8, promotes transcription of RNAPII-specific spliceosomal snRNA and small nucleolar RNA (snoRNA) genes. The 7SK snRNA specifically associates with a fraction of RNAPII hyperphosphorylated at Ser5 and Ser7, which is a hallmark of RNAPII engaged in snRNA synthesis. Chromatin immunoprecipitation (ChIP) and chromatin isolation by RNA purification (ChIRP) experiments revealed enrichments for all components of the 7SK snRNP on RNAPII-specific sn/snoRNA genes. Depletion of 7SK snRNA or Larp7 disrupts LEC integrity, inhibits RNAPII recruitment to RNAPII-specific sn/snoRNA genes, and reduces nascent snRNA and snoRNA synthesis. Thus, through controlling both mRNA elongation and sn/snoRNA synthesis, the 7SK snRNP is a key regulator of nuclear RNA production by RNAPII. © 2017 The Authors.

The Protein Kinase SmSnRK2.6 Positively Regulates Phenolic Acid Biosynthesis in Salvia miltiorrhiza by Interacting with SmAREB1.

Science.gov (United States)

Jia, Yanyan; Bai, Zhenqing; Pei, Tianlin; Ding, Kai; Liang, Zongsuo; Gong, Yuehua

2017-01-01

Subclass III members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2) play essential roles in both the abscisic acid signaling and abiotic stress responses of plants by phosphorylating the downstream ABA-responsive element (ABRE)-binding proteins (AREB/ABFs). This comprehensive study investigated the function of new candidate genes, namely SmSnRK2.3 , SmSnRK2.6 , and SmAREB1 , with a view to breeding novel varieties of Salvia miltiorrhiza with improved stress tolerance stresses and more content of bioactive ingredients. Exogenous ABA strongly induced the expression of these genes. PlantCARE predicted several hormones and stress response cis -elements in their promoters. SmSnRK2.6 and SmAREB1 showed the highest expression levels in the leaves of S. miltiorrhiza seedlings, while SmSnRK2.3 exhibited a steady expression in their roots, stems, and leaves. A subcellular localization assay revealed that both SmSnRK2.3 and SmSnRK2.6 were located in the cell membrane, cytoplasm, and nucleus, whereas SmAREB1 was exclusive to the nucleus. Overexpressing SmSnRK2.3 did not significantly promote the accumulation of rosmarinic acid (RA) and salvianolic acid B (Sal B) in the transgenic S. miltiorrhiza hairy roots. However, overexpressing SmSnRK2.6 and SmAREB1 increased the contents of RA and Sal B, and regulated the expression levels of structural genes participating in the phenolic acid-branched and side-branched pathways, including SmPAL1 , SmC4H , Sm4CL1 , SmTAT , SmHPPR , SmRAS , SmCHS , SmCCR , SmCOMT , and SmHPPD . Furthermore, SmSnRK2.3 and SmSnRK2.6 interacted physically with SmAREB1. In summary, our results indicate that SmSnRK2.6 is involved in stress responses and can regulate structural gene transcripts to promote greater metabolic flux to the phenolic acid-branched pathway, via its interaction with SmAREB1 , a transcription factor. In this way, SmSnRK2.6 contributes to the positive regulation of phenolic acids in S. miltiorrhiza hairy roots.

The Protein Kinase SmSnRK2.6 Positively Regulates Phenolic Acid Biosynthesis in Salvia miltiorrhiza by Interacting with SmAREB1

Directory of Open Access Journals (Sweden)

Yanyan Jia

2017-08-01

Full Text Available Subclass III members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2 play essential roles in both the abscisic acid signaling and abiotic stress responses of plants by phosphorylating the downstream ABA-responsive element (ABRE-binding proteins (AREB/ABFs. This comprehensive study investigated the function of new candidate genes, namely SmSnRK2.3, SmSnRK2.6, and SmAREB1, with a view to breeding novel varieties of Salvia miltiorrhiza with improved stress tolerance stresses and more content of bioactive ingredients. Exogenous ABA strongly induced the expression of these genes. PlantCARE predicted several hormones and stress response cis-elements in their promoters. SmSnRK2.6 and SmAREB1 showed the highest expression levels in the leaves of S. miltiorrhiza seedlings, while SmSnRK2.3 exhibited a steady expression in their roots, stems, and leaves. A subcellular localization assay revealed that both SmSnRK2.3 and SmSnRK2.6 were located in the cell membrane, cytoplasm, and nucleus, whereas SmAREB1 was exclusive to the nucleus. Overexpressing SmSnRK2.3 did not significantly promote the accumulation of rosmarinic acid (RA and salvianolic acid B (Sal B in the transgenic S. miltiorrhiza hairy roots. However, overexpressing SmSnRK2.6 and SmAREB1 increased the contents of RA and Sal B, and regulated the expression levels of structural genes participating in the phenolic acid-branched and side-branched pathways, including SmPAL1, SmC4H, Sm4CL1, SmTAT, SmHPPR, SmRAS, SmCHS, SmCCR, SmCOMT, and SmHPPD. Furthermore, SmSnRK2.3 and SmSnRK2.6 interacted physically with SmAREB1. In summary, our results indicate that SmSnRK2.6 is involved in stress responses and can regulate structural gene transcripts to promote greater metabolic flux to the phenolic acid-branched pathway, via its interaction with SmAREB1, a transcription factor. In this way, SmSnRK2.6 contributes to the positive regulation of phenolic acids in S. miltiorrhiza hairy roots.

Facile synthesis and optical property of SnO2 flower-like architectures

International Nuclear Information System (INIS)

Zhao Qingrui; Li Zhengquan; Wu Changzheng; Bai Xue; Xie Yi

2006-01-01

Two-dimensional (2D) hierarchical tin dioxide (SnO 2 ) flower-like architectures consisting of sheet-like nanoparticles have been successfully prepared by a simply mild hydrothermal method based on the reaction between tin foil, NaOH and KBrO 3 . The photoluminescence (PL) spectrum exhibit that the flower-like architectures of SnO 2 have strong PL emission, which suggest its possible applications in nanoscaled optoelectronic devices. The formation process of SnO 2 architectures is investigated and the corresponding mechanism is also proposed

Influence of Sn content on microstructural and mechanical properties of centrifugal cast Ti-Nb-Sn biomedical alloys

International Nuclear Information System (INIS)

Lopes, E.S.N.; Contieri, R.J.; Caram, R.; Costa, A.M.S.

2010-01-01

The arc voltaic centrifugal casting is an interesting alternative in terms of economic and technological development in the production of components based on materials with high reactivity and high melting point, such as titanium alloys. In this work, Ti-30Nb (wt. %) with additions of Sn (2, 4, 6, 8 and 10 wt. %) were formed by casting process. Characterization of the samples included optical microscopy, scanning electron microscopy, X-ray diffraction, Vickers hardness and elastic modulus measures by acoustic techniques. It was observed that the microstructure of the samples investigated is composed by dendritic structures, with clear segregation of alloying elements. The Vickers hardness and the elastic modulus decreased with the addition of Sn. The results show that the mechanical behavior of Ti-Nb alloys can be controlled within certain limits, by adding Sn. (author)

Internal friction behavior of liquid Bi-Sn alloys

International Nuclear Information System (INIS)

Wu Aiqing; Guo Lijun; Liu Changsong; Jia Erguang; Zhu Zhengang

2005-01-01

Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480 - bar Cand another at about 830 - bar C. Only a single internal-friction peak at about 830 - bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids

Internal friction behavior of liquid Bi-Sn alloys

Energy Technology Data Exchange (ETDEWEB)

Wu Aiqing [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Guo Lijun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Liu Changsong [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Jia Erguang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China); Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031 (China)]. E-mail: zgzhu@issp.ac.cn

2005-12-01

Pure Bi and Sn and four Bi-Sn alloys distributed on the entire concentration range were selected for internal-friction investigation over a wide temperature range. There exist two peaks in the plots of internal friction versus temperature for liquid Sn, Bi-Sn60 and Bi-Sn90 alloys, one peak being located at about 480{sup -}bar Cand another at about 830{sup -}bar C. Only a single internal-friction peak at about 830{sup -}bar C occurs in liquid Bi-Sn43 (eutectic composition). No internal-friction peak appears in liquid Bi-Sn20 alloy and pure Bi. The height of the internal-friction peaks depends on the content of Sn. The present finding suggests that Sn-rich Bi-Sn alloys may inherit the internal-friction behaviors of pure Sn, whereas Bi-rich Bi-Sn alloy seems to be like pure Bi. The position of the internal-friction peaks is frequency dependent, which resembles the internal-friction feature in structure transition in solids.

Single-Crystal Growth of Cl-Doped n-Type SnS Using SnCl2 Self-Flux.

Science.gov (United States)

Iguchi, Yuki; Inoue, Kazutoshi; Sugiyama, Taiki; Yanagi, Hiroshi

2018-06-05

SnS is a promising photovoltaic semiconductor owing to its suitable band gap energy and high optical absorption coefficient for highly efficient thin film solar cells. The most significant carnage is demonstration of n-type SnS. In this study, Cl-doped n-type single crystals were grown using SnCl 2 self-flux method. The obtained crystal was lamellar, with length and width of a few millimeters and thickness ranging between 28 and 39 μm. X-ray diffraction measurements revealed the single crystals had an orthorhombic unit cell. Since the ionic radii of S 2- and Cl - are similar, Cl doping did not result in substantial change in lattice parameter. All the elements were homogeneously distributed on a cleaved surface; the Sn/(S + Cl) ratio was 1.00. The crystal was an n-type degenerate semiconductor with a carrier concentration of ∼3 × 10 17 cm -3 . Hall mobility at 300 K was 252 cm 2 V -1 s -1 and reached 363 cm 2 V -1 s -1 at 142 K.

Structural, optical, and improved photocatalytic properties of CdS/SnO_2 hybrid photocatalyst nanostructure

International Nuclear Information System (INIS)

Venkata Reddy, Ch.; Ravikumar, R.V.S.S.N.; Srinivas, Ganganagunta; Shim, Jaesool; Cho, Migyung

2017-01-01

Highlights: • CdS, SnO_2, and a CdS/SnO_2 hybrid photocatalyst were synthesized using a two-step technique. • The dislocation density, strain values are higher for CdS/SnO_2 hybrid photocatalyst. • The CdS/SnO_2 has a higher surface area and smaller crystallite size compared to pristine CdS. • The CdS/SnO_2 catalyst greatly reduced recombination of electron and hole pairs. - Abstract: CdS, SnO_2 and CdS/SnO_2 hybrid photocatalyst nanostructure were synthesized using a two-step (co-precipitation/hydrothermal) method. The as-prepared materials were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), surface analysis (BET), photoluminescence spectra (PL), UV–Vis diffusion reflectance spectroscopy (DRS), fourier transform infrared spectroscopy (FT-IR), and photocatalytic activity. The band gap energies calculated from the DRS results are 3.30, 2.15, and 2.99 eV for pristine SnO_2, CdS, and the CdS/SnO_2 hybrid photocatalyst, respectively. The CdS/SnO_2 hybrid photocatalyst showed more efficient charge carrier separation and improved photocatalytic degradation of methyl orange (MO). The highest degradation rate constant was achieved for the CdS/SnO_2 hybrid photocatalyst (0.02434 min"−"1) compared to CdS (0.01381 min"−"1) and SnO_2 (0.00878 min"−"1). The present study provides insights for improving the photocatalytic activity and photo-stability of CdS/SnO_2 hybrid photocatalyst.

The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode As Deflagrations?

Energy Technology Data Exchange (ETDEWEB)

Phillips, M.M.; Li, W.; Frieman, J.A.; Blinnikov, S.I.; DePoy, D.; Prieto, J.L.; Milne, P.; Contreras, C.; Folatelli, Gaston; Morrell, N.; Hamuy, M.; Suntzeff, N.B.; Roth, M.; Gonzalez, S.; Krzeminski, W.; Filippenko, A.V.; Freedman, W.L.; Chornock, R.; Jha, S.; Madore, B.F.; Persson, S.E.; /Las Campanas Observ. /UC, Berkeley, Astron. Dept.

2006-11-14

We present extensive u{prime}g{prime}r{prime}i{prime} BV RIY JHK{sub s} photometry and optical spectroscopy of SN 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called 'the most peculiar known type Ia supernova'. Both supernovae exhibited high ionization SN 1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal type Ia supernovae. Our Y JH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from {approx} 10 days before to {approx}60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a 3D deflagration which produces {approx} 0.25 M{sub {circle_dot}} of {sup 56}Ni.

Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds

Science.gov (United States)

Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

2018-02-01

The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.

Scintillation and optical properties of Sn-doped Ga2O3 single crystals

Science.gov (United States)

Usui, Yuki; Nakauchi, Daisuke; Kawano, Naoki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

2018-06-01

Sn-doped Ga2O3 single crystals were synthesized by the Floating Zone (FZ) method. In photoluminescence (PL) under the excitation wavelength of 280 nm, we observed two types of luminescence: (1) defect luminescence due to recombination of the donor/acceptor pairs which appears at 430 nm and (2) the nsnp-ns2 transitions of Sn2+ which appear at 530 nm. The PL and scintillation decay time curves of the Sn-doped samples were approximated by a sum of exponential decay functions. The faster two components were ascribed to the defect luminescence, and the slowest component was owing to the nsnp-ns2 transitions. In the pulse height spectrum measurements under 241Am α-rays irradiation, all the Sn-doped Ga2O3 samples were confirmed to show a full energy absorption peak but the undoped one. Among the present samples, the 1% Sn-doped sample exhibited the highest scintillation light yield (1,500 ± 150 ph/5.5 MeV-α).

The Transition of a Type IIL Supernova into a Supernova Remnant: Late-time Observations of SN 2013by

Energy Technology Data Exchange (ETDEWEB)

Black, C. S.; Fesen, R. A. [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Milisavljevic, D.; Patnaude, D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Margutti, R. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Parker, S. [Parkdale Observatory, 225 Warren Road, RDl Oxford, Canterbury 7495 (New Zealand)

2017-10-10

We present early-time Swift and Chandra X-ray data along with late-time optical and near-infrared observations of SN 2013by, a Type IIL supernova (SN) that occurred in the nearby spiral galaxy ESO 138−G10 ( D ∼ 14.8 Mpc). Optical and NIR photometry and spectroscopy follow the late-time evolution of the SN from days +89 to +457 post maximum brightness. The optical spectra and X-ray light curves are consistent with the picture of an SN having prolonged interaction with circumstellar material (CSM) that accelerates the transition from SN to supernova remnant (SNR). Specifically, we find SN 2013by’s H α profile exhibits significant broadening (∼10,000 km s{sup −1}) on day +457, the likely consequence of high-velocity, H-rich material being excited by a reverse shock. A relatively flat X-ray light curve is observed that cannot be modeled using Inverse Compton scattering processes alone, but requires an additional energy source most likely originating from the SN-CSM interaction. In addition, we see the first overtone of CO emission near 2.3 μ m on day +152, signaling the formation of molecules and dust in the SN ejecta and is the first time CO has been detected in a Type IIL SN. We compare SN 2013by with Type IIP SNe, whose spectra show the rarely observed SN-to-SNR transition in varying degrees and conclude that Type IIL SNe may enter the remnant phase at earlier epochs than their Type IIP counterparts.

Changes of electronic structure of SnTe due to high concentration of Sn vacancies

International Nuclear Information System (INIS)

Masek, J.; Nuzhnyj, D.N.

1997-01-01

Non-stoichiometric Sn 1-y Te is a strongly degenerated n-type semiconductor. This is important for understanding unusual features of magnetic behaviour of Sn 1-x Gd x Te where the relative positions of the Fermi energy and the atomic d-level of Gd govern the exchange coupling.The influence of the Sn vacancies on the band structure cannot be neglect if their concentration reaches a few atomic percent. We address this problem by using a tight-binding coherent potential approach and show that although the character of the bands remains unchanged, they are modified so that ε d can come out above the heavy-hole band. (author)

Electrochemical synthesis of nanostructured Se-doped SnS: Effect of Se-dopant on surface characterizations

Energy Technology Data Exchange (ETDEWEB)

Kafashan, Hosein, E-mail: hosein840521@gmail.com; Azizieh, Mahdi; Balak, Zohre

2017-07-15

Highlights: • Nanostructured SnS{sub 1-x}Se{sub x} thin films were prepared by using electrodeposition method. • The XRD patterns obviously showed that the synthesized films were polycrystalline. • The PL spectra of SnS{sub 1-x}Se{sub x} thin films showed four emission peaks. • The UV–vis spectra shows a variation in the optical band gap energy of SnS{sub 1-x}Se{sub x} thin films from 1.22 to 1.65 eV. • SnS{sub 1-x}Se{sub x} thin films would be suitable for use as absorber layers. - Abstract: SnS{sub 1-x}Se{sub x} nanostructures with different Se-dopant concentrations were deposited on fluorine doped tin oxide (FTO) substrate through cathodic electrodeposition technique. The pH, temperature, applied potential (E), and deposition time remained were 2.1, 60 °C, −1 V, and 30 min, respectively. SnS{sub 1-x}Se{sub x} nanostructures were characterized using X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), energy dispersive X-ray spectroscopy (EDX), room temperature photoluminescence (PL), and UV–vis spectroscopy. The XRD patterns revealed that the SnS{sub 1-x}Se{sub x} nanostructures were polycrystalline with orthorhombic structure. FESEM showed various kinds of morphologies in SnS{sub 1-x}Se{sub x} nanostructures due to Se-doping. PL and UV–vis spectroscopy were used to evaluate the optical properties of SnS{sub 1-x}Se{sub x} thin films. The PL spectra of SnS{sub 1-x}Se{sub x} nanostructures displayed four emission peaks, those are a blue, a green, an orange, and a red emission. UV–vis spectra showed that the optical band gap energy (E{sub g}) of SnS{sub 1-x}Se{sub x} nanostructures varied between 1.22–1.65 eV, due to Se-doping.

Electrochemical synthesis of nanostructured Se-doped SnS: Effect of Se-dopant on surface characterizations

Science.gov (United States)

Kafashan, Hosein; Azizieh, Mahdi; Balak, Zohre

2017-07-01

SnS1-xSex nanostructures with different Se-dopant concentrations were deposited on fluorine doped tin oxide (FTO) substrate through cathodic electrodeposition technique. The pH, temperature, applied potential (E), and deposition time remained were 2.1, 60 °C, -1 V, and 30 min, respectively. SnS1-xSex nanostructures were characterized using X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), energy dispersive X-ray spectroscopy (EDX), room temperature photoluminescence (PL), and UV-vis spectroscopy. The XRD patterns revealed that the SnS1-xSex nanostructures were polycrystalline with orthorhombic structure. FESEM showed various kinds of morphologies in SnS1-xSex nanostructures due to Se-doping. PL and UV-vis spectroscopy were used to evaluate the optical properties of SnS1-xSex thin films. The PL spectra of SnS1-xSex nanostructures displayed four emission peaks, those are a blue, a green, an orange, and a red emission. UV-vis spectra showed that the optical band gap energy (Eg) of SnS1-xSex nanostructures varied between 1.22-1.65 eV, due to Se-doping.

`Pd20Sn13' revisited: crystal structure of Pd6.69Sn4.31

Directory of Open Access Journals (Sweden)

Wilhelm Klein

2015-07-01

Full Text Available The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarah et al. (1981. Z. Metallkd, 72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6 were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtained via a solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2 type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3:0.62 (3. One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3a and 3b.

Optical studies on Sn, K, Hg{sub 2} I{sub 2}, and I{sub 2}-doped {alpha}-HgI{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, M.; Ibarra, A.; Willmott, C.; Pascual, J. L.; Dieguez, E.

1997-07-01

The influence on the optical properties of {alpha}-mercuric iodide stoichiometric deviations have been investigated. The optical behaviour of samples doped with Sn (IV) and K were also studied. To prepare mercury-rich and iodide rich samples (non-stoichiometric compounds), vapour phase crystal growth was performed on a closed ampoule with a mercurous iodide or iodine atmosphere, respectively. Dopants were introduced through the vapour phase by means of Snl{sub 4} and KI vapours during crystal growth. A decrease in the energy gap is deduced from the optical absorption spectra taken on non-stoichiometric and doped samples. Photoluminescence was also performed as a function of temperature while samples were under uniaxial pressure. Differences between doped, non-stoichiometric and pure samples are observed on luminescence emission wavelength and intensity.

Transport, Optical, and Magnetic Properties of the Conducting Halide Perovskite CH 3NH 3SnI 3

Science.gov (United States)

Mitzi, D. B.; Feild, C. A.; Schlesinger, Z.; Laibowitz, R. B.

1995-01-01

A low-temperature ( T ≤ 100°C) solution technique is described for the preparation of polycrystalline and single crystal samples of the conducting halide perovskite, CH 3NH 3SnI 3. Transport, Hall effect, magnetic, and optical properties are examined over the temperature range 1.8-300 K, confirming that this unusual conducting halide perovskite is a low carrier density p-type metal with a Hall hole density, 1/ RHe ≃ 2 × 10 19 cm -3. The resistivity of pressed pellet samples decreases with decreasing temperature with resistivity ratio ρ(300 K)/ρ(2 K) ≃ 3 and room temperature resistivity ρ(300 K) ≃ 7 mΩ-cm. A free-carrier infrared reflectivity spectrum with a plasma edge observed at approximately 1600 cm -1 further attests to the metallic nature of this compound and suggests a small optical effective mass, m* ≃ 0.2.

Quasi-two-dimensional thermoelectricity in SnSe

Science.gov (United States)

Tayari, V.; Senkovskiy, B. V.; Rybkovskiy, D.; Ehlen, N.; Fedorov, A.; Chen, C.-Y.; Avila, J.; Asensio, M.; Perucchi, A.; di Pietro, P.; Yashina, L.; Fakih, I.; Hemsworth, N.; Petrescu, M.; Gervais, G.; Grüneis, A.; Szkopek, T.

2018-01-01

Stannous selenide is a layered semiconductor that is a polar analog of black phosphorus and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle-resolved photoemission spectroscopy, optical reflection spectroscopy, and magnetotransport measurements reveal a multiple-valley valence-band structure and a quasi-two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250 cm2/V s at T =1.3 K . SnSe is thus found to be a high-quality quasi-two-dimensional semiconductor ideal for thermoelectric applications.

Fabrication and sulfurization of Cu{sub 2}SnS{sub 3} thin films with tuning the concentration of Cu-Sn-S precursor ink

Energy Technology Data Exchange (ETDEWEB)

Wang, Chi-Jie [Institute of Microelectronics & Department of Electrical Engineering, National Cheng Kung University, Taiwan (China); Shei, Shih-Chang, E-mail: scshei@mail.nutn.edu.tw [Department of Electrical Engineering, Nation University of Tainan, Taiwan (China); Chang, Shih-Chang [Department of Electrical Engineering, Nation University of Tainan, Taiwan (China); Chang, Shoou-Jinn [Institute of Microelectronics & Department of Electrical Engineering, National Cheng Kung University, Taiwan (China)

2016-12-01

Highlights: • Tuning the relative reaction rate of component phases proved to be beneficial in controlling the reaction process. • Low-concentration samples display closely packed Cu{sub 2}SnS{sub 3} grains with a flat morphology. • Optical band-gap energy measured at 1.346 eV suitable for thin-film solar cell applications. - Abstract: In this study, Cu-Sn-S nanoinks were synthesized by combining chelating polyetheramine to Cu, Sn, S powders of various concentrations. X-ray diffraction patterns indicate that nanoinks synthesized at low concentrations are composed almost entirely of binary phases SnS and Cu{sub 2}S. Synthesizing nanoinks at higher concentrations decreased the quantity of binary phase and led to the appearance of ternary phase Cu{sub 4}SnS{sub 4}. Following sulfurization, single phase Cu{sub 2}SnS{sub 3} (CTS) thin film was obtained from nanoinks of low concentration; however, impurities, such as Cu{sub 2}S were detected in the thin film obtained from nanoinks of high concentration. This can be attributed to the fact that lower concentrations reduce the reactivity of all the elements. As a result, the SnS phase reacted more readily and more rapidly, resulting in the early formation of a stoichiometric CTS thin film during sulfurization. Under these reaction conditions, Cu{sub 2}S and SnS transform into CTS and thereby prevent the formation of unwanted phases of Cu{sub 2}S and Cu{sub 4}SnS{sub 4}. Raman spectra revealed that second phase Cu{sub 2}S phase remained in the high-concentration samples, due to an increase in reactivity due to the participation of a greater proportion of the copper in the reaction. The surface microstructure of low-concentration samples display closely packed Cu{sub 2}SnS{sub 3} grains with a flat morphology and an atomic composition ratio of Cu:Sn:S = 34.69:15.90:49.41, which is close to stoichiometric. Hall measurement revealed that low-concentration sample has superior electrical properties; i.e., a hole

Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

International Nuclear Information System (INIS)

Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

2014-01-01

Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

Late-time spectral line formation in Type IIb supernovae, with application to SN 1993J, SN 2008ax, and SN 2011dh

Science.gov (United States)

Jerkstrand, A.; Ergon, M.; Smartt, S. J.; Fransson, C.; Sollerman, J.; Taubenberger, S.; Bersten, M.; Spyromilio, J.

2015-01-01

disappear as the optical depths decrease with time. The modelled evolution of this effect matches the observed evolution in SN 2011dh. Appendices are available in electronic form at http://www.aanda.org

Zr-doped SnO2 thin films synthesized by spray pyrolysis technique for barrier layers in solar cells

Science.gov (United States)

Reddy, N. Nanda Kumar; Akkera, Harish Sharma; Sekhar, M. Chandra; Park, Si-Hyun

2017-12-01

In the present work, we investigated the effect of Zr doping (0-6 at%) on the structural, electrical, and optical properties of tin oxide (SnO2) thin films deposited onto glass substrates using a spray pyrolysis technique. The room-temperature X-ray diffraction pattern shows that all deposited films exhibit polycrystalline tetragonal structure. The pure SnO2 film is grown along a preferred (200) direction, whereas Zr-doped SnO2 (Zr:SnO2) films started growing along the (220) orientation along with a high intensity peak of (200). Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed that the grains of the films are spherical in structure, and the grain size decreased with increasing of Zr concentration. The optical transmission spectra of deposited films as a function of wavelength confirm that the average optical transmittance is > 85% for Zr:SnO2 films. The value of the optical bandgap is significantly decreased from 3.94 to 3.68 eV with increasing Zr concentration. Furthermore, the electrical measurements found that the sheet resistance ( R sh) and resistivity ( ρ) values are decreased with increasing of Zr doping. The lowest values of R sh = 6.82 Ω and ρ = 0.4 × 10- 3 Ω cm are found in 6-at% Zr-doped SnO2 film. In addition, a good efficiency value of the figure of merit ( ɸ = 3.35 × 10- 3 Ω-1) is observed in 6-at% Zr-doped SnO2 film. These outstanding properties of Zr-doped SnO2 films make them useful for several optoelectronic device applications.

A study of structural, electrical, and optical properties of p-type Zn-doped SnO2 films versus deposition and annealing temperature

Science.gov (United States)

Le, Tran; Phuc Dang, Huu; Luc, Quang Ho; Hieu Le, Van

2017-04-01

This study presents a detailed investigation of the structural, electrical, and optical properties of p-type Zn-doped SnO2 versus the deposition and annealing temperature. Using a direct-current (DC) magnetron sputtering method, p-type transparent conductive Zn-doped SnO2 (ZTO) films were deposited on quartz glass substrates. Zn dopants incorporated into the SnO2 host lattice formed the preferred dominant SnO2 (1 0 1) and (2 1 1) planes. X-ray photoelectron spectroscopy (XPS) was used for identifying the valence state of Zn in the ZTO film. The electrical property of ZTO films changed from n-type to p-type at the threshold temperature of 400 °C, and the films achieved extremely high conductivity at the optimum annealing temperature of 600 °C after annealing for 2 h. The best conductive property of the film was obtained on a 10 wt% ZnO-doped SnO2 target with a resistivity, hole concentration, and hole mobility of 0.22 Ω · cm, 7.19  ×  1018 cm-3, and 3.95 cm2 V-1 s-1, respectively. Besides, the average transmission of films was  >84%. The surface morphology of films was examined using scanning electron microscopy (SEM). Moreover, the acceptor level of Zn2+ was identified using photoluminescence spectra at room temperature. Current-voltage (I-V) characteristics revealed the behavior of a p-ZTO/n-Si heterojunction diode.

CuLi2Sn and Cu2LiSn: Characterization by single crystal XRD and structural discussion towards new anode materials for Li-ion batteries.

Science.gov (United States)

Fürtauer, Siegfried; Effenberger, Herta S; Flandorfer, Hans

2014-12-01

The stannides CuLi 2 Sn (CSD-427095) and Cu 2 LiSn (CSD-427096) were synthesized by induction melting of the pure elements and annealing at 400 °C. The phases were reinvestigated by X-ray powder and single-crystal X-ray diffractometry. Within both crystal structures the ordered CuSn and Cu 2 Sn lattices form channels which host Cu and Li atoms at partly mixed occupied positions exhibiting extensive vacancies. For CuLi 2 Sn, the space group F-43m. was verified (structure type CuHg 2 Ti; a =6.295(2) Å; wR 2 ( F ²)=0.0355 for 78 unique reflections). The 4( c ) and 4( d ) positions are occupied by Cu atoms and Cu+Li atoms, respectively. For Cu 2 LiSn, the space group P 6 3 / mmc was confirmed (structure type InPt 2 Gd; a =4.3022(15) Å, c =7.618(3) Å; wR 2 ( F ²)=0.060 for 199 unique reflections). The Cu and Li atoms exhibit extensive disorder; they are distributed over the partly occupied positions 2( a ), 2( b ) and 4( e ). Both phases seem to be interesting in terms of application of Cu-Sn alloys as anode materials for Li-ion batteries.

THE LONG-LIVED UV ''PLATEAU'' OF SN 2012aw

Energy Technology Data Exchange (ETDEWEB)

Bayless, Amanda J.; Roming, Peter W. A. [Southwest Research Institute, Department of Space Science, 6220 Culebra Road, San Antonio, TX 78238 (United States); Pritchard, Tyler A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Kuin, Paul [Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Brown, Peter J. [Texas A and M University, Department of Physics and Astronomy, College Station, TX 77843-4242 (United States); Botticella, Maria Teresa; Dall' Ora, Massimo [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Napoli (Italy); Frey, Lucille H.; Even, Wesley; Fryer, Chris L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maund, Justyn R.; Fraser, Morgan [Astrophysics Research Center, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom)

2013-02-10

Observations with the Swift UV Optical Telescope have unambiguously uncovered for the first time a long-lived, UV ''plateau'' in a Type II-P supernova (SN). Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band light curves initially declined rapidly, but 27 days after the explosion the light curves flattened. Some possible sources of the UV plateau are the same thermal process that causes the optical plateau, heating from radioactive decay, or a combination of both processes.

Design of Optical Pulse Position Modulation (PPM) Translating Receiver

Energy Technology Data Exchange (ETDEWEB)

Mendez, A J; Hernandez, V J; Gagliardi, R M; Bennett, C V

2009-06-19

M-ary pulse position modulation (M-ary PPM) signaling is a means of transmitting multiple bits per symbol in an intensity modulated/direct detection (IM/DD) system. PPM is used in applications with average power limitations. In optical communication systems, PPM becomes challenging to implement at gigabit rates and/or large M, since pulsed signaling requires higher electronic processing bandwidths than the fundamental transmission rate. they have thus been exploring techniques for PPM communications using optical processing. Previous work described a transmitter algorithm that directly translates a bit sequence of N digital bits to the optical pulse position m for any M = 2{sup N}. It has been considerably more difficult to define a similar receiver algorithm that translates the received optical pulse position directly back to a bit sequence with minimal electronic processing. Designs for specific Ms (e.g., 4-ary) have been shown and implemented, but are difficult to scale to larger M. In this work, they present for the first time a generalized PPM translating receiver that is applicable to all M and data rates.

Structural and optical analysis of 60Co gamma-irradiated thin films of polycrystalline Ga10Se85Sn5

Science.gov (United States)

Ahmad, Shabir; Asokan, K.; Shahid Khan, Mohd.; Zulfequar, M.

2015-12-01

The present study focuses on the effects of gamma irradiation on structural and optical properties of polycrystalline Ga10Se85Sn5 thin films with a thickness of ∼300 nm deposited by the thermal evaporation technique on cleaned glass substrates. X-ray diffraction patterns of the investigated thin films show that crystallite growth occurs in the orthorhombic phase structure. The surface study carried out by using the scanning electron microscope (SEM) confirms that the grain size increases with gamma irradiation. The optical parameters were estimated from optical transmission spectra data measured from a UV-vis-spectrophotometer in the wavelength range of 200-1100 nm. The refractive index dispersion data of the investigated thin films follow the single oscillator model. The estimated values of static refractive index n0, oscillator strength Ed, zero frequency dielectric constant ε0, optical conductivity σoptical and the dissipation factor increases after irradiation, while the single oscillator energy Eo decreases after irradiation. It was found that the value of the optical band gap of the investigated thin films decreases and the corresponding absorption coefficient increases continuously with an increase in the dose of gamma irradiation. This post irradiation changes in the values of optical band gap and absorption coefficient were interpreted in terms of the bond distribution model.

Compositional Dependence of Optical and Structural Properties of Nanogranular Mixed ZrO2/ZnO/SnO2 Thin Film

Science.gov (United States)

Salari, S.; Ghodsi, F. E.

2018-06-01

A study on the optical properties and photoluminescence (PL) spectra of ternary oxide nanogranular thin films comprising Zr, Zn, and Sn revealed that the change in component ratio could direct the roadmap to improve characteristics of the films. Grazing angle X-ray diffraction analysis showed that incorporation of Sn atoms into the tetragonal structure of Zn/Zr thin film resulted in an amorphous structure. The band gap of film was tunable by precisely controlling the concentration of components. The widening of band gap could correlate to the quantum confinement effect. PL spectra of the composite thin films under excitation at 365 nm showed a sharp red emission with relatively Gaussian line shape, which was intensified in the optimum percentage ratio of 50/30/20. This nearly red emission is attributed to the radiative emission of electrons captured at low-energy traps located near the valence band. An optimum red emission is strongly desirable for use in white LEDs. The comparative study on FTIR spectra of unary, binary, and ternary thin films confirmed successful composition of three different metal oxides in ternary thin films. Detailed investigation on FTIR spectra of ternary compounds revealed that the quenching in PL emission at higher percentage of Sn was originally due to the hydroxyl group.

Structural, optical, and improved photocatalytic properties of CdS/SnO{sub 2} hybrid photocatalyst nanostructure

Energy Technology Data Exchange (ETDEWEB)

Venkata Reddy, Ch., E-mail: cvrphy@gmail.com [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522510 (India); Srinivas, Ganganagunta [Engineering Department, lbra College of Technology, lbra 400 (Oman); Shim, Jaesool, E-mail: jshim@ynu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Cho, Migyung, E-mail: mgcho@tu.ac.kr [Department of Game Engineering, Tongmyong University, Busan 608-711 (Korea, Republic of)

2017-07-15

Highlights: • CdS, SnO{sub 2}, and a CdS/SnO{sub 2} hybrid photocatalyst were synthesized using a two-step technique. • The dislocation density, strain values are higher for CdS/SnO{sub 2} hybrid photocatalyst. • The CdS/SnO{sub 2} has a higher surface area and smaller crystallite size compared to pristine CdS. • The CdS/SnO{sub 2} catalyst greatly reduced recombination of electron and hole pairs. - Abstract: CdS, SnO{sub 2} and CdS/SnO{sub 2} hybrid photocatalyst nanostructure were synthesized using a two-step (co-precipitation/hydrothermal) method. The as-prepared materials were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), surface analysis (BET), photoluminescence spectra (PL), UV–Vis diffusion reflectance spectroscopy (DRS), fourier transform infrared spectroscopy (FT-IR), and photocatalytic activity. The band gap energies calculated from the DRS results are 3.30, 2.15, and 2.99 eV for pristine SnO{sub 2}, CdS, and the CdS/SnO{sub 2} hybrid photocatalyst, respectively. The CdS/SnO{sub 2} hybrid photocatalyst showed more efficient charge carrier separation and improved photocatalytic degradation of methyl orange (MO). The highest degradation rate constant was achieved for the CdS/SnO{sub 2} hybrid photocatalyst (0.02434 min{sup −1}) compared to CdS (0.01381 min{sup −1}) and SnO{sub 2} (0.00878 min{sup −1}). The present study provides insights for improving the photocatalytic activity and photo-stability of CdS/SnO{sub 2} hybrid photocatalyst.

SN 2011A: A Low-luminosity Interacting Transient with a Double Plateau and Strong Sodium Absorption

Science.gov (United States)

de Jaeger, T.; Anderson, J. P.; Pignata, G.; Hamuy, M.; Kankare, E.; Stritzinger, M. D.; Benetti, S.; Bufano, F.; Elias-Rosa, N.; Folatelli, G.; Förster, F.; González-Gaitán, S.; Gutiérrez, C. P.; Inserra, C.; Kotak, R.; Lira, P.; Morrell, N.; Taddia, F.; Tomasella, L.

2015-07-01

We present optical photometry and spectroscopy of the optical transient SN 2011A. Our data span 140 days after discovery including {BVRI} u\\prime g\\prime r\\prime i\\prime z\\prime photometry and 11 epochs of optical spectroscopy. Originally classified as a type IIn supernova (SN IIn) due to the presence of narrow Hα emission, this object shows exceptional characteristics. First, the light curve shows a double plateau, a property only observed before in the impostor SN 1997bs. Second, SN 2011A has a very low luminosity ({M}V=-15.72), placing it between normal luminous SNe IIn and SN impostors. Third, SN 2011A shows low velocity and high equivalent width absorption close to the sodium doublet, which increases with time and is most likely of circumstellar origin. This evolution is also accompanied by a change in line profile; when the absorption becomes stronger, a P Cygni profile appears. We discuss SN 2011A in the context of interacting SNe IIn and SN impostors, which appears to confirm the uniqueness of this transient. While we favor an impostor origin for SN 2011A, we highlight the difficulty in differentiating between terminal and non-terminal interacting transients. This paper includes data obtained with the 6.5 m Magellan Telescopes and du Pont telescope; the Gemini-North Telescope, Mauna Kea, USA (Gemini Program GN-2010B-Q67, PI: Stritzinger); the PROMPT telescopes at Cerro Tololo Inter-American Observatory in Chile; with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council; based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias; the NTT from ESO Science Archive

Computational assessment of promising mid-infrared nonlinear optical materials Mg–IV–V2 (IV = Si, Ge, Sn; V = P, As): a first-principles study

Science.gov (United States)

Xiao, Jianping; Zhu, Shifu; Zhao, Beijun; Chen, Baojun; Liu, Hui; He, Zhiyu

2018-03-01

The mid-infrared (mid-IR) nonlinear optical (NLO) capabilities of Mg–IV–V2 (IV = Si, Ge, Sn; V = P, As) are systematically assessed by the first-principles calculation. The results show that the compounds in this group except MgSiP2 and MgSnP2 have moderate birefringence values to fulfill the phase-matching conditions. In particular, MgGeP2 and MgSiAs2 possess relatively large band gaps and almost three to four times larger static SHG coefficients than the benchmark material AgGaSe2, exhibiting good potential for mid-IR NLO application. According to the detailed analysis of the electronic structures, it is found that the dominant SHG contributions are from the orbitals of the asymmetry anionic unit [IV–V2]2‑. Moreover, the further evaluation reveals that MgSiAs2, MgGeAs2, MgSnP2 and MgSnAs2 are not thermodynamically stable and the new synthesis strategy (i.e. synthesis under non-equilibrium conditions) should be considered.

Comparison of the electrochemical performance of mesoscopic Cu2Sb, SnSb and Sn/SnSb alloy powders

International Nuclear Information System (INIS)

Zhang Ge; Huang Kelong; Liu Suqin; Zhang Wei; Gong Benli

2006-01-01

Cu 2 Sb, SnSb and Sn/SnSb mesoscopic alloy powders were prepared by chemical reduction, respectively. The crystal structures and particle morphology of Cu 2 Sb, SnSb and Sn/SnSb were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The electrochemical performances of the Cu 2 Sb, SnSb and Sn/SnSb electrodes were investigated by galvanostatic charge and discharge cycling and electrochemical impedance spectroscopy (EIS). The results showed the first charge and discharge capacities of SnSb and Sn/SnSb were higher than Cu 2 Sb, but after 15 cycles, the charge capacity fading rates of Cu 2 Sb, Sn/SnSb and Sn/SnSb were 26.16%, 55.33% and 47.39%, respectively. Cu 2 Sb had a better cycle performance, and Sn/SnSb multiphase alloy was prior to pure SnSb due to the existence of excessive Sn in Sn/SnSb system

Nanocrystalline sol-gel TiO{sub 2}-SnO{sub 2} coatings: Preparation, characterization and photo-catalytic performance

Energy Technology Data Exchange (ETDEWEB)

Kaleji, Behzad Koozegar [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Sarraf-Mamoory, Rasoul, E-mail: rsarrafm@modares.ac.ir [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

2012-02-15

Highlights: Black-Right-Pointing-Pointer SnO{sub 2} additive enhanced significantly photo-catalytic properties of TiO{sub 2} based thin film for remove of organic compounds. Black-Right-Pointing-Pointer Structural and optical properties are dependent on dopant concentration. Black-Right-Pointing-Pointer TiO{sub 2}-SnO{sub 2} nanocrystalline thin film is promising for photocatalytic properties in visible light. -- Abstract: In this study, preparation of SnO{sub 2} (0-30 mol% SnO{sub 2})-TiO{sub 2} dip-coated thin films on glazed porcelain substrates via sol-gel process has been investigated. The effects of SnO{sub 2} on the structural, optical, and photo-catalytic properties of applied thin films have been studied by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Surface topography and surface chemical state of thin films were examined by atomic force microscopy and X-ray photoelectron spectroscopy. XRD patterns showed an increase in peak intensities of the rutile crystalline phase by increasing the SnO{sub 2} content. The prepared Sn doped TiO{sub 2} photo-catalyst films showed optical absorption in the visible light area exhibited excellent photo-catalytic ability for the degradation of methylene blue under visible light irradiation. Best photo-catalytic activity of Sn doped TiO{sub 2} thin films was measured in the TiO{sub 2}-15 mol% SnO{sub 2} sample by the Sn{sup 4+} dopants presented substitution Ti{sup 4+} into the lattice of TiO{sub 2} increasing the surface oxygen vacancies and the surface hydroxyl groups.

SnO{sub 2} thin films morphological and optical properties in terms of the Boubaker Polynomials Expansion Scheme BPES-related Opto-Thermal Expansivity {psi}{sub AB}

Energy Technology Data Exchange (ETDEWEB)

Amlouk, A.; Boubaker, K. [Unite de physique des dispositifs a semi-conducteurs, Faculte des sciences de Tunis, Universite de Tunis El Manar, 2092 Tunis (Tunisia); Amlouk, M., E-mail: mmbb11112000@yahoo.f [Unite de physique des dispositifs a semi-conducteurs, Faculte des sciences de Tunis, Universite de Tunis El Manar, 2092 Tunis (Tunisia)

2010-02-04

In this study, SnO{sub 2} thin films have been grown using spray pyrolysis technique on glass substrates under a substrate temperature (T{sub s} = 440 {sup o}C). The precursors were methanol CH{sub 4}O and anhydrous tin tetrachloride. XRD analyses yielded strong (1 1 0)-(1 0 1)-(2 0 0) X-ray diffraction peaks which are characteristics to tetragonal crystals. Atomic Force Microscopy (AFM) analyses showed the existence of clusters with particular pyramidal shapes. The main part of this study concerns the optical measurements of transmittance T({lambda}) and reflectance R({lambda}) spectra inside 250-1800 nm domain. Conjoint optical and thermal properties were deduced using the Amlouk-Boubaker Opto-Thermal Expansivity {psi}{sub AB}. The obtained value: {psi}{sub AB} {approx} 23.4 m{sup 3} s{sup -1} helped situating the performance of the as-grown SnO{sub 2} compound among most known PV-T oxides like ZnO and TiO{sub 2}.

Optoelectronic properties of SnO2 thin films sprayed at different deposition times

Science.gov (United States)

Allag, Abdelkrim; Saâd, Rahmane; Ouahab, Abdelouahab; Attouche, Hafida; Kouidri, Nabila

2016-04-01

This article presents the elaboration of tin oxide (SnO2) thin films on glass substrates by using a home-made spray pyrolysis system. Effects of film thickness on the structural, optical, and electrical film properties are investigated. The films are characterized by several techniques such as x-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible (UV-Vis) transmission, and four-probe point measurements, and the results suggest that the prepared films are uniform and well adherent to the substrates. X-ray diffraction (XRD) patterns show that SnO2 film is of polycrystal with cassiterite tetragonal crystal structure and a preferential orientation along the (110) plane. The calculated grain sizes are in a range from 32.93 nm to 56.88 nm. Optical transmittance spectra of the films show that their high transparency average transmittances are greater than 65% in the visible region. The optical gaps of SnO2 thin films are found to be in a range of 3.64 eV-3.94 eV. Figures of merit for SnO2 thin films reveal that their maximum value is about 1.15 × 10-4 Ω-1 at λ = 550 nm. Moreover, the measured electrical resistivity at room temperature is on the order of 10-2 Ω·cm.

F-doped SnO2 thin films grown on flexible substrates at low temperatures by pulsed laser deposition

International Nuclear Information System (INIS)

Kim, H.; Auyeung, R.C.Y.; Pique, A.

2011-01-01

Fluorine-doped tin oxide (SnO 2 :F) films were deposited on polyethersulfone plastic substrates by pulsed laser deposition. The electrical and optical properties of the SnO 2 :F films were investigated as a function of deposition conditions such as substrate temperature and oxygen partial pressure during deposition. High quality SnO 2 :F films were achieved under an optimum oxygen pressure range (7.4-8 Pa) at relatively low growth temperatures (25-150 deg. C). As-deposited films exhibited low electrical resistivities of 1-7 mΩ-cm, high optical transmittance of 80-90% in the visible range, and optical band-gap energies of 3.87-3.96 eV. Atomic force microscopy measurements revealed a reduced root mean square surface roughness of the SnO 2 :F films compared to that of the bare substrates indicating planarization of the underlying substrate.

THIRTY YEARS OF SN 1980K: EVIDENCE FOR LIGHT ECHOES

Energy Technology Data Exchange (ETDEWEB)

Sugerman, Ben E. K. [Department of Physics and Astronomy, Goucher College, 1021 Dulaney Valley Road, Baltimore, MD 21208 (United States); Andrews, Jennifer E. [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Barlow, Michael J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Clayton, Geoffrey C. [Department of Physics and Astronomy, Lousiana State University, 202 Nicholson Hall, Baton Roughe, LA 70803 (United States); Ercolano, Barbara [Excellence Cluster ' Universe' , Universitaets-Sternwarte Muenchen, Scheinerstr. 1, 81679 Muenchen (Germany); Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Smith Hall, Towson, MD 21252 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CM3 0HA (United Kingdom); Krause, Oliver [Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg (Germany); Meixner, Margaret [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Otsuka, Masaaki, E-mail: ben.sugerman@goucher.edu [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)

2012-04-20

We report optical and mid-infrared photometry of SN 1980K between 2004 and 2010, which shows slow monotonic fading consistent with previous spectroscopic and photometric observations made 8-17 yr after outburst. The slow rate of change over two decades suggests that this evolution may result from scattered and thermal light echoes off of extended circumstellar material. We present a semi-analytic dust radiative-transfer model that uses an empirically corrected effective optical depth to provide a fast and robust alternative to full Monte Carlo radiative-transfer modeling for homogenous dust at low to intermediate optical depths. We find that unresolved echoes from a thin circumstellar shell 14-15 lt-yr from the progenitor, and containing {approx}< 0.02 M{sub Sun} of carbon-rich dust, can explain the broadband spectral and temporal evolution. The size, mass, and dust composition are in good agreement with the contact discontinuity observed in scattered echoes around SN 1987A. The origin of slowly changing high-velocity [O I] and H{alpha} lines is also considered. We propose an origin in shocked high-velocity metal-rich clumps of ejecta, rather than arising in the impact of ejecta on slowly moving circumstellar material, as is the case with hot spots in SN 1987A.

SnSe Nanocrystals: Synthesis, Structure, Optical Properties, and Surface Chemistry

KAUST Repository

Baumgardner, William J.; Choi, Joshua J.; Lim, Yee-Fun; Hanrath, Tobias

2010-01-01

The colloidal synthesis of SnSe nanoparticles is accomplished through the injection of bis[bis(trimethylsilyl)amino]tin(II) into hot trioctylphosphine: selenium in the presence of oleylamine. Through the manipulation of reaction temperature particles are grown with the average diameter reliably tuned to 4-10 nm. Quantum confinement is examined by establishing a relationship between particle size and band gap while the in depth growth dynamics are illuminated through UV-vis-NIR spectroscopy. Surface chemistry effects are explored, including the demonstration of useful ligand exchanges and the development of routes toward anisotropic particle growth. Finally, transient current-voltage properties of SnSe nanocrystal films in the dark and light are examined. © 2010 American Chemical Society.

SnSe Nanocrystals: Synthesis, Structure, Optical Properties, and Surface Chemistry

KAUST Repository

Baumgardner, William J.

2010-07-21

The colloidal synthesis of SnSe nanoparticles is accomplished through the injection of bis[bis(trimethylsilyl)amino]tin(II) into hot trioctylphosphine: selenium in the presence of oleylamine. Through the manipulation of reaction temperature particles are grown with the average diameter reliably tuned to 4-10 nm. Quantum confinement is examined by establishing a relationship between particle size and band gap while the in depth growth dynamics are illuminated through UV-vis-NIR spectroscopy. Surface chemistry effects are explored, including the demonstration of useful ligand exchanges and the development of routes toward anisotropic particle growth. Finally, transient current-voltage properties of SnSe nanocrystal films in the dark and light are examined. © 2010 American Chemical Society.

Kinetics of plasma oxidation of germanium-tin (GeSn)

Science.gov (United States)

Wang, Wei; Lei, Dian; Dong, Yuan; Zhang, Zheng; Pan, Jisheng; Gong, Xiao; Tok, Eng-Soon; Yeo, Yee-Chia

2017-12-01

The kinetics of plasma oxidation of GeSn at low temperature is investigated. The oxidation process is described by a power-law model where the oxidation rate decreases rapidly from the initial oxidation rate with increasing time. The oxidation rate of GeSn is higher than that of pure Ge, which can be explained by the higher chemical reaction rate at the GeSn-oxide/GeSn interface. In addition, the Sn atoms at the interface region exchange positions with the underlying Ge atoms during oxidation, leading to a SnO2-rich oxide near the interface. The bandgap of GeSn oxide is extracted to be 5.1 ± 0.2 eV by XPS, and the valence band offset at the GeSn-oxide/GeSn heterojunction is found to be 3.7 ± 0.2 eV. Controlled annealing experiments demonstrate that the GeSn oxide is stable with respect to annealing temperatures up to 400 °C. However, after annealing at 450 °C, the GeO2 is converted to GeO, and desorbs from the GeSn-oxide/GeSn, leaving behind Sn oxide.

Field emission from patterned SnO2 nanostructures

International Nuclear Information System (INIS)

Zhang Yongsheng; Yu Ke; Li Guodong; Peng Deyan; Zhang Qiuxiang; Hu Hongmei; Xu Feng; Bai Wei; Ouyang Shixi; Zhu Ziqiang

2006-01-01

A simple and reliable method has been developed for synthesizing finely patterned tin dioxide (SnO 2 ) nanostructure arrays on silicon substrates. A patterned Au catalyst film was prepared on the silicon wafer by radio frequency (RF) magnetron sputtering and photolithographic patterning processes. The patterned SnO 2 nanostructures arrays, a unit area is of ∼500 μm x 200 μm, were synthesized via vapor phase transport method. The surface morphology and composition of the as-synthesized SnO 2 nanostructures were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanism of formation of SnO 2 nanostructures was also discussed. The measurement of field emission (FE) revealed that the as-synthesized SnO 2 nanorods, nanowires and nanoparticles arrays have a lower turn-on field of 2.6, 3.2 and 3.9 V/μm, respectively, at the current density of 0.1 μA/cm 2 . This approach must have a wide variety of applications such as fabrications of micro-optical components and micropatterned oxide thin films used in FE-based flat panel displays, sensor arrays and so on

Hydrodynamical models of supernova SN 1987 A in the LMC

International Nuclear Information System (INIS)

Grassberg, E.K.; Imshennik, V.S.; Nadezhin, D.K.; Utrobin, V.P.

1987-01-01

It is shown that the properties of SN 1987A in LMC can be described well by hydrodynamical models of explosions of compact massive stars. In accordance with these models, the mass of the expelled envelope the presupernova radius and the total energy of explosion are evaluated for SN 1987A to be ∼ 16M Sun , ∼ 30R Sun , and ∼ 3.10 51 erg, respectively. The progenitor of supernova remnant Cas A may be considered as the prototype to the SN 1987A in our own Galaxy. In other galaxies, this subtype of supernovae can be represented by SN 1948B in NGC6946. If energy of explosion transfers from collapsed core of the star to the envelope within timescale less than 1 hour, then delay Δt ∼ 3 hours between the neutrino pulse and the steep rise of optical luminosity of SN 1987A does not contradict with scenario of explosions of compact massive stars

The role of Tin Oxide Concentration on The X-ray Diffraction, Morphology and Optical Properties of In2O3:SnO2 Thin Films

Science.gov (United States)

Hasan, Bushra A.; Abdallah, Rusul M.

2018-05-01

Alloys were performed from In2O3 doped SnO2 with different doping ratio by quenching from the melt technique. Pulsed Laser Deposition PLD was used to deposit thin films of different doping ratio In2O3 : SnO2 (0, 1, 3, 5, 7 and 9 % wt.) on glass substrate at ambient temperature under vacuum of 10-3 bar thickness of ∼100nm. The structural type,grain size and morphology of the prepared alloys compounds and thin films were examined using X-ray diffraction and atomic force microscopy. The results showed that all alloys have polycrystalline structures and the peaks belonged to the preferred plane for crystal growth were identical with the ITO (Indium – Tin –Oxide) standard cards also another peaks were observed belonged to SnO2 phase. The structures of thin films was also polycrystalline, and the predominate peaks are identical with standard cards ITO. On the other side the prepared thin films declared decrease a reduction of degree of crystallinity with the increase of doping ratio. Atomic Force Microscopy AFM measurements showed the average grain size and average surface roughness exhibit to change in systematic manner with the increase of doping ratio with tin oxide. The optical measurements show that the In2O3:SnO2 thin films have a direct energy gap Eg opt in the first stage decreases with the increase of doping ratio and then get to increase with further increase of doping ration, whereas reverse to that the optical constants such as refractive index (n), extinction coefficient (k) and dielectric constant (εr, εi) have a regular increase with the doping ratio by tin oxide and then decreases.

Swift heavy ion irradiated SnO_2 thin film sensor for efficient detection of SO_2 gas

International Nuclear Information System (INIS)

Tyagi, Punit; Sharma, Savita; Tomar, Monika; Singh, Fouran; Gupta, Vinay

2016-01-01

Highlights: • Response of Ni"7"+ ion irradiated (100 MeV) SnO_2 film have been performed. • Effect of irradiation on the structural and optical properties of SnO_2 film is studied. • A decrease in operating temperature and increased response is seen after irradiation. - Abstract: Gas sensing response studies of the Ni"7"+ ion irradiated (100 MeV) and non-irradiated SnO_2 thin film sensor prepared under same conditions have been performed towards SO_2 gas (500 ppm). The effect of irradiation on the structural, surface morphological, optical and gas sensing properties of SnO_2 thin film based sensor have been studied. A significant decrease in operating temperature (from 220 °C to 60 °C) and increased sensing response (from 1.3 to 5.0) is observed for the sample after irradiation. The enhanced sensing response obtained for the irradiated SnO_2 thin film based sensor is attributed to the desired modification in the surface morphology and material properties of SnO_2 thin film by Ni"7"+ ions.

Compensation and persistent photocapacitance in homoepitaxial Sn-doped β-Ga2O3

Science.gov (United States)

Polyakov, A. Y.; Smirnov, N. B.; Shchemerov, I. V.; Gogova, D.; Tarelkin, S. A.; Pearton, S. J.

2018-03-01

The electrical properties of epitaxial β-Ga2O3 doped with Sn (1016-9 × 1018 cm-3) and grown by metalorganic chemical vapor deposition on semi-insulating β-Ga2O3 substrates are reported. Shallow donors attributable to Sn were observed only in a narrow region near the film/substrate interface and with a much lower concentration than the total Sn density. For heavily Sn doped films (Sn concentration, 9 × 1018 cm-3), the electrical properties in the top portion of the layer were determined by deep centers with a level at Ec-0.21 eV not described previously. In more lightly doped layers, the Ec-0.21 eV centers and deeper traps at Ec-0.8 eV were present, with the latter pinning the Fermi level. Low temperature photocapacitance and capacitance voltage measurements of illuminated samples indicated the presence of high densities (1017-1018 cm-3) of deep acceptors with an optical ionization threshold of 2.3 eV. Optical deep level transient spectroscopy (ODLTS) and photoinduced current transient spectroscopy (PICTS) detected electron traps at Ec-0.8 eV and Ec-1.1 eV. For lightly doped layers, the compensation of film conductivity was mostly provided by the Ec-2.3 eV acceptors. For heavily Sn doped films, deep acceptor centers possibly related to Ga vacancies were significant. The photocapacitance and the photocurrent caused by illumination at low temperatures were persistent, with an optical threshold of 1.9 eV and vanished only at temperatures of ˜400 K. The capture barrier for electrons causing the persistent photocapacitance effect was estimated from ODLTS and PICTS to be 0.25-0.35 eV.

On the Disappearance of the Supergiant Progenitor of SN 2011dh in M51.

Science.gov (United States)

Ergon, Mattias; Sollerman, Jesper; Pursimo, Tapio; Augusteijn, Thomas; Telting, John; Smirnova, Olesja; Kankare, Erkki; Mattila, Seppo; Maund, Justyn; Fraser, Morgan

2013-03-01

We report on high quality pre- and post-explosion B, V and r band imaging obtained with the 2.56 m Nordic Optical Telescope (NOT). Difference imaging reveals a reduction of 45-60 percent in flux at the position of the yellow supergiant coincident with SN 2011dh and proposed as the progenitor by Maund et al. (2011, ApJ, 739, L37). The pre-explosion imaging was obtained on May 26 2008 (B) and May 29 2011 (V and r), the latter just 2 days before explosion.

Irradiated Graphene Loaded with SnO₂ Quantum Dots for Energy Storage.

Science.gov (United States)

Huang, Ruting; Wang, Lijun; Zhang, Qian; Chen, Zhiwen; Li, Zhen; Pan, Dengyu; Zhao, Bing; Wu, Minghong; Wu, C M Lawrence; Shek, Chan-Hung

2015-11-24

Tin dioxide (SnO2) and graphene are unique strategic functional materials with widespread technological applications, particularly in the areas of solar batteries, optoelectronic devices, and solid-state gas sensors owing to advances in optical and electronic properties. Versatile strategies for microstructural evolution and related performance of SnO2 and graphene composites are of fundamental importance in the development of electrode materials. Here we report that a novel composite, SnO2 quantum dots (QDs) supported by graphene nanosheets (GNSs), has been prepared successfully by a simple hydrothermal method and electron-beam irradiation (EBI) strategies. Microstructure analysis indicates that the EBI technique can induce the exfoliation of GNSs and increase their interlayer spacing, resulting in the increase of GNS amorphization, disorder, and defects and the removal of partial oxygen-containing functional groups on the surface of GNSs. The investigation of SnO2 nanoparticles supported by GNSs (SnO2/GNSs) reveals that the GNSs are loaded with SnO2 QDs, which are dispersed uniformly on both sides of GNSs. Interestingly, the electrochemical performance of SnO2/GNSs indicates that SnO2 QDs supported by a 210 kGy irradiated GNS shows excellent cycle response, high specific capacity, and high reversible capacity. This novel SnO2/GNS composite has potential practical applications in SnO2 electrode materials during Li(+) insertion/extraction.

Phase controlled solvothermal synthesis of Cu_2ZnSnS_4, Cu_2ZnSn(S,Se)_4 and Cu_2ZnSnSe_4 Nanocrystals: The effect of Se and S sources on phase purity

International Nuclear Information System (INIS)

Pal, Mou; Mathews, N.R.; Paraguay-Delgado, F.; Mathew, X.

2015-01-01

In this study, we have reported the synthesis of Cu_2ZnSnSe_4 (CZTSe), Cu_2ZnSnS_4 (CZTS) and Cu_2ZnSn(S,Se)_4 (CZTSSe) nanocrystals with tunable band gap and composition obtained by solvothermal method. The crystalline structure, composition, morphology and optical properties of the nanoparticles were characterized by X-ray diffraction (XRD), Raman scattering, energy dispersive X-ray spectroscopy, transmission electron microscopy and diffuse reflectance (DR) spectroscopy. While the XRD patterns of CZTS and CZTSe nanoparticles prepared with elemental S/Se powder revealed the presence of phase pure nanoparticles, the CZTSSe nanoparticles obtained using a mixture of S and Se, were found to contain many secondary phases under the same synthesis protocol. Formation of impurity phases in CZTSSe sample, can be avoided by using a mixture of 1-dodecanethiol (DT; CH_3(CH_2)_1_1SH)/oleylamine (OLA) instead of S powder and following the same experimental procedure. The incorporation of S in CZTSe nanocrystals prepared in presence of DDT/OLA mixture was confirmed through structural and optical characterizations. The optical properties of the quaternary chalcogenide nanocrystals were found to vary with the chemical composition of the material. - Highlights: • Solvothermal synthesis of CZTS, CZTSSe and CZTSe nanocrystals and discussion on possible formation mechanism. • Use of dodecanethiol/oleylamine mixture to synthesize phase-pure CZTSSe nanocrystals. • Formation of impurity phases can be controlled with proper S and Se sources.

Study of sub band gap absorption of Sn doped CdSe thin films

International Nuclear Information System (INIS)

Kaur, Jagdish; Rani, Mamta; Tripathi, S. K.

2014-01-01

The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively

Study of sub band gap absorption of Sn doped CdSe thin films

Energy Technology Data Exchange (ETDEWEB)

Kaur, Jagdish; Rani, Mamta [Department of Physics, Panjab University, Chandigarh- 160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Panjab University, Chandigarh- 160014 (India)

2014-04-24

The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively.

Hierarchical Models for Type Ia Supernova Light Curves in the Optical and Near Infrared

Science.gov (United States)

Mandel, Kaisey; Narayan, G.; Kirshner, R. P.

2011-01-01

I have constructed a comprehensive statistical model for Type Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic model coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical model to analyze nearby Type Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the model predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical model. The continued observation and analysis of Type Ia SN in the optical and near infrared is important for improving their utility as precise and accurate cosmological distance indicators.

Optoelectronic properties of SnO2 thin films sprayed at different deposition times

International Nuclear Information System (INIS)

Abdelkrim, Allag; Rahmane, Saâd; Abdelouahab, Ouahab; Hafida, Attouche; Nabila, Kouidri

2016-01-01

This article presents the elaboration of tin oxide (SnO 2 ) thin films on glass substrates by using a home-made spray pyrolysis system. Effects of film thickness on the structural, optical, and electrical film properties are investigated. The films are characterized by several techniques such as x-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible (UV–Vis) transmission, and four-probe point measurements, and the results suggest that the prepared films are uniform and well adherent to the substrates. X-ray diffraction (XRD) patterns show that SnO 2 film is of polycrystal with cassiterite tetragonal crystal structure and a preferential orientation along the (110) plane. The calculated grain sizes are in a range from 32.93 nm to 56.88 nm. Optical transmittance spectra of the films show that their high transparency average transmittances are greater than 65% in the visible region. The optical gaps of SnO 2 thin films are found to be in a range of 3.64 eV–3.94 eV. Figures of merit for SnO 2 thin films reveal that their maximum value is about 1.15 × 10 −4 Ω −1 at λ = 550 nm. Moreover, the measured electrical resistivity at room temperature is on the order of 10 −2 Ω·cm. (paper)

MAPLE deposition and characterization of SnO2 colloidal nanoparticle thin films

International Nuclear Information System (INIS)

Caricato, A P; Martino, M; Romano, F; Tunno, T; Valerini, D; Epifani, M; Rella, R; Taurino, A

2009-01-01

In this paper we report on the deposition and characterization of tin oxide (SnO 2 ) nanoparticle thin films. The films were deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. SnO 2 colloidal nanoparticles with a trioctylphosphine capping layer were diluted in toluene with a concentration of 0.2 wt% and frozen at liquid nitrogen temperature. The frozen target was irradiated with a KrF (248 nm, τ = 20 ns) excimer laser (6000 pulses at 10 Hz). The nanoparticles were deposited on silica (SiO 2 ) and (1 0 0) Si substrates and submitted to morphological (high resolution scanning electron microscopy (SEM)), structural Fourier transform infrared spectroscopy (FTIR) and optical (UV-Vis transmission) characterizations. SEM and FTIR analyses showed that trioctylphosphine was the main component in the as-deposited films. The trioctylphosphine was removed after an annealing in vacuum at 400 0 C, thus allowing to get uniform SnO 2 nanoparticle films in which the starting nanoparticle dimensions were preserved. The energy gap value, determined by optical characterizations, was 4.2 eV, higher than the bulk SnO 2 energy gap (3.6 eV), due to quantum confinement effects.

Mode division multiplexing technology for single-fiber optical trapping axial-position adjustment.

Science.gov (United States)

Liu, Zhihai; Wang, Lei; Liang, Peibo; Zhang, Yu; Yang, Jun; Yuan, Libo

2013-07-15

We demonstrate trapped yeast cell axial-position adjustment without moving the optical fiber in a single-fiber optical trapping system. The dynamic axial-position adjustment is realized by controlling the power ratio of the fundamental mode beam (LP01) and the low-order mode beam (LP11) generated in a normal single-core fiber. In order to separate the trapping positions produced by the two mode beams, we fabricate a special fiber tapered tip with a selective two-step method. A yeast cell of 6 μm diameter is moved along the optical axis direction for a distance of ~3 μm. To the best of our knowledge, this is the first demonstration of the trapping position adjustment without moving the fiber for single-fiber optical tweezers. The excitation and utilization of multimode beams in a single fiber constitutes a new development for single-fiber optical trapping and makes possible more practical applications in biomedical research fields.

Improved axial position detection in optical tweezers measurements

DEFF Research Database (Denmark)

Dreyer, Jakob Kisbye; Berg-Sørensen, Kirstine; Oddershede, Lene

2004-01-01

We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial...... position displays complex behavior with regions of positive and negative interference. By analyzing the scattered light intensity as a function of the axial position of the trapped sphere, we propose a simple method to increase the sensitivity and control the linear range of axial position detection....

Synthesis and evaluation of optical and antimicrobial properties of Ag-SnO2 nanocomposites

Science.gov (United States)

Kumar Nair, Kishore; Kumar, Promod; Kumar, Vinod; Harris, R. A.; Kroon, R. E.; Viljoen, Bennie; Shumbula, P. M.; Mlambo, M.; Swart, H. C.

2018-04-01

We report on the sol-gel based room temperature synthesis of undoped SnO2 and Ag-SnO2 nanostructures. The synthesized nanostructures were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, High-resolution transmission electron microscopy (HR-TEM) and UV-visible spectroscopy. The XRD pattern confirmed that the obtained nanostructures have a tetragonally rutile structure. No extra phase changes were observed after Ag doping. UV-visible spectroscopy measurements indicated that the band gap of 3.59 eV for pure SnO2 nanostructures, decreased to 3.39 eV after doping. TEM analysis showed that no regular shape morphology existed and some rod-shaped particles were also detected in the nanostructures. The antibacterial activity of the nanostructures against E. coli was evaluated and a continuous decrease of microbial count was observed. The microbial population decreased from 6 × 105 cfu/ml to 7 × 104 cfu/ml and 5 × 104 cfu/ml on SnO2 and Ag-SnO2 treatments, respectively. Thus, the nanostructures can be used for the biorational management of E. coli for waste water treatment before discharge.

Surface tension and wetting behaviour of Bi-In-Sn alloys

International Nuclear Information System (INIS)

Ervina Efzan Mohd Noor; Ahmad Badri Ismail; Soong, T.K.; Chin, Y.T.; Luay Bakir Hussain

2007-01-01

Concerns about possible landfill contamination, influent discharge from production process are one of the reasons convert from lead-containing electronics to lead-free containing. The surface and interfacial properties of Bi-In-Sn lead-free solder system as a basic system of multicomponent alloys proposed as lead-free solder materials have been studied. The surface tension of Bi-In-Sn lead-free solder system of melting temperature 60 degree Celsius has been measured the temperature range 80 degree Celsius and 140 degree Celsius. The study of the wetting behaviour of Bi-In-Sn lead-free solder system on a Cu substrate has been performed by measuring contact angle on various metal substrates by Optical Microscopy with software. (author)

Deposition and characterization of single magnetron deposited Fe:SnO{sub x} coatings

Energy Technology Data Exchange (ETDEWEB)

Kormunda, Martin, E-mail: martin.kormunda@ujep.cz [J.E. Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Fischer, Daniel; Hertwig, Andreas; Beck, Uwe [BAM Federal Institute for Materials Research and Testing, Division 6 4 Surface Technologies, Unter den Eichen 44-46, 12203 Berlin (Germany); Sebik, Matej; Pavlik, Jaroslav [J.E. Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem (Czech Republic); Esser, Norbert [Leibniz-Institut für Analytische Wissenschaften — ISAS e.V., Department Berlin, Schwarzschildstr. 12, 12489 Berlin (Germany)

2015-11-30

Coatings deposited by magnetron co-sputtering from a single RF magnetron with a ceramic SnO{sub 2} target with iron inset in argon plasma were studied. The mass spectra of the process identified Sn{sup +} and SnO{sup +} species as the dominant species sputtered from the target, but no SnO{sub 2}{sup +} species were detected. The dominant positive ions in argon plasma are Ar{sup +} species. The only detected negative ions were O{sup −}. Sputtered neutral tin related species were not detected. Iron related species were also not detected because their concentration is below the detection limit. The concentration of iron dopant in the tin oxide coatings was controlled by the RF bias applied on the substrate holder while the discharge pressure also has some influence. The iron concentration was in the range from 0.9 at.% up to 19 at.% increasing with the substrate bias while the sheet resistivity decreases. The stoichiometry ratio of O/(Sn + Fe) in the coatings increased from 1.7 up to 2 in dependence on the substrate bias from floating bias (− 5 V) up to − 120 V of RF self-bias, respectively. The tin in the coatings was mainly bonded in Sn{sup 4+} state and iron was mainly in Fe{sup 2+} state when other tin bonding states were detected only in a small amounts. Iron bonding states in contrary to elemental compositions of the coatings were not influenced by the RF bias applied on the substrate. The coatings showed high transparency in the visible spectral range. However, an increased metallic behavior could be detected by using a higher RF bias for the deposition. The X-ray diffraction patterns and electron microscopy pictures made on the coatings confirmed the presence of an amorphous phase. - Highlights: • RF magnetron sputtering of SnO{sub 2} target with Fe inset in argon investigated by mass spectrometry • Optical properties of Fe doped SnO{sub x} coatings characterized • Analyses of overlapped XPS peaks at a spectrum from Fe doped SnO{sub x} coatings �

Morphologically controlled synthesis, structural and optical properties of CeO2/SnO2 nanocomposites

Directory of Open Access Journals (Sweden)

S. Usharani

2017-09-01

Full Text Available CeO2/SnO2 nanocomposites with different dimensional nanostructures were synthesized by a wet chemical method, using various surfactants such as SDS, CTAB and Triton X-100. The prepared CeO2/SnO2 samples were analyzed by X-ray diffraction (XRD, Fourier transform infrared (FTIR, Transmission electron microscopy (TEM, UV-Diffuse Reflectance Spectroscopy (UV-DRS, and Photoluminescence (PL spectroscopy. The XRD patterns reveal the presence of a mixed phase of SnO2 and CeO2; The TEM analysis showed the mixed morphology of uniformly dispersed spherical with ellipsoidal shape in the SDS assisted CeO2/SnO2 nanocomposites; whereas the nanostructure with spherical with hexagonal shapes was observed for the Triton X-100 assisted CeO2/SnO2 nanocomposites. The one dimensional (1D nanorod like structure observed for the CTAB assisted CeO2/SnO2 nanocomposites shows CTAB acting as a face-specific capping agent to form rod-shaped micelles. The room temperature photoluminescence emission studies of the CeO2/SnO2 nanocomposites showed strong peaks in the UV region, and several peaks in the visible region, which are likely to have originated from the oxygen vacancies and are potential materials for optoelectronic device applications. The UV results showed the absorption edges shifted to a high energy region and the blue shifts that occurred in all the samples.

Toward quantum-limited position measurements using optically levitated microspheres

International Nuclear Information System (INIS)

Libbrecht, Kenneth G.; Black, Eric D.

2004-01-01

We propose the use of optically levitated microspheres as test masses in experiments aimed at reaching and potentially exceeding the standard quantum limit for position measurements. Optically levitated microspheres have low mass and are essentially free of suspension thermal noise, making them well suited for experimentally testing our understanding of quantum-limited measurements

Toward quantum-limited position measurements using optically levitated microspheres

Energy Technology Data Exchange (ETDEWEB)

Libbrecht, Kenneth G.; Black, Eric D

2004-01-26

We propose the use of optically levitated microspheres as test masses in experiments aimed at reaching and potentially exceeding the standard quantum limit for position measurements. Optically levitated microspheres have low mass and are essentially free of suspension thermal noise, making them well suited for experimentally testing our understanding of quantum-limited measurements.

Copper tin sulfide (CTS) absorber thin films obtained by co-evaporation: Influence of the ratio Cu/Sn

Energy Technology Data Exchange (ETDEWEB)

Robles, V., E-mail: victor.robles@ciemat.es; Trigo, J.F.; Guillén, C.; Herrero, J.

2015-09-05

Highlights: • Copper tin sulfide (CTS) thin films were grown by co-evaporation at different Cu/Sn atomic ratios. • Smooth Cu{sub 2}SnS{sub 3} layers with large grains are obtained at Cu/Sn ⩾ 1.5 and T ⩾ 350 °C. • At 450 °C, the cubic Cu{sub 2}SnS{sub 3} phase changes to tetragonal phase. • Cu{sub 2}SnS{sub 3} presents suitable optical and electrical properties for use as photovoltaic absorbers. - Abstract: Copper tin sulfide thin films have been grown on soda-lime glass substrates from the elemental constituents by co-evaporation. The synthesis was performed at substrate temperatures of 350 °C and 450 °C and different Cu/Sn ratios, adjusting the deposition time in order to obtain thicknesses above 1000 nm. The evolution of the morphological, structural, chemical, optical and electrical properties has been analyzed as a function of the substrate temperature and the Cu/Sn ratio. For the samples with Cu/Sn ⩽ 1, Cu{sub 2}Sn{sub 3}S{sub 7} and Cu{sub 2}SnS{sub 3} have been observed by XRD. Increasing the Cu/Sn to 1.5, the Cu{sub 2}SnS{sub 3} phase was the majority, being the formation completed at Cu/Sn ratio around 2. The increment of the substrate temperature leads to a change of cubic structure to tetragonal of the Cu{sub 2}SnS{sub 3} phase. The chemical treatment with KCN was effective to eliminate CuS excess detected in the samples with Cu/Sn > 2.2. The samples with Cu{sub 2}SnS{sub 3} structure show a band gap energy increasing from 0.9 to 1.25 eV and an electrical resistivity decreasing from 7 ∗ 10{sup −2} Ω cm to 3 ∗ 10{sup −3} Ω cm when the Cu/Sn atomic ratio increases from 1.5 to 2.2.

The ASAS-SN Catalog of Variable Stars I: The Serendipitous Survey

Science.gov (United States)

Jayasinghe, T.; Kochanek, C. S.; Stanek, K. Z.; Shappee, B. J.; Holoien, T. W.-S.; Thompson, Todd A.; Prieto, J. L.; Dong, Subo; Pawlak, M.; Shields, J. V.; Pojmanski, G.; Otero, S.; Britt, C. A.; Will, D.

2018-04-01

The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of ˜2 - 3 days down to V≲ 17 mag. ASAS-SN has monitored the whole sky since 2014, collecting ˜100 - 500 epochs of observations per field. The V-band light curves for candidate variables identified during the search for supernovae are classified using a random forest classifier and visually verified. We present a catalog of 66,533 bright, new variable stars discovered during our search for supernovae, including 27,753 periodic variables and 38,780 irregular variables. V-band light curves for the ASAS-SN variables are available through the ASAS-SN variable stars database (https://asas-sn.osu.edu/variables). The database will begin to include the light curves of known variable stars in the near future along with the results for a systematic, all-sky variability survey.

Optical and electrical properties of thermally evaporated In49Se48Sn3 films

International Nuclear Information System (INIS)

Salem, A.M.; El-Gendy, Y.A.; El-Sayad, E.A.

2009-01-01

Nearly stoichiometric thin films of In 49 Se 48 Sn 3 were deposited at room temperature, by conventional thermal evaporation of the presynthesized materials, onto precleaned glass substrates. The microstructural studies on the as-deposited and annealed films, using transmission electron microscopy and diffraction (TEMD), revealed that the as-deposited films are amorphous in nature, while those annealed at 498 K are crystalline. The optical properties of the investigated films were determined from the transmittance and reflectance data, in the spectral range 650-2500 nm. An analysis of the optical absorption spectra revealed a non-direct energy gap characterizing the amorphous films, while both allowed and forbidden direct energy gaps characterized the crystalline films. The electrical resistance of the deposited films was carried out during heating and cooling cycles in the temperature range 300-600 K. The results show an irreproducible behavior, while after crystallization the results become reproducible. The analysis of the temperature dependence of the resistance (ln(R) vs. 1000/T) for crystalline films shows two straight lines corresponding to both extrinsic and intrinsic conduction. The room temperature I-V characteristics of the as-deposited films sandwiched between similar Ag metal electrodes shows an ohmic behavior, while non-ohmic behavior attributed to space charge limited conduction has been observed when the films are sandwiched between dissimilar Ag/Al metal electrodes.

Microstructure, corrosion behavior and cytotoxicity of biodegradable Mg-Sn implant alloys prepared by sub-rapid solidification.

Science.gov (United States)

Zhao, Chaoyong; Pan, Fusheng; Zhao, Shuang; Pan, Hucheng; Song, Kai; Tang, Aitao

2015-09-01

In this study, biodegradable Mg-Sn alloys were fabricated by sub-rapid solidification, and their microstructure, corrosion behavior and cytotoxicity were investigated by using optical microscopy, scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy, X-ray diffraction, immersion test, potentiodynamic polarization test and cytotoxicity test. The results showed that the microstructure of Mg-1Sn alloy was almost equiaxed grain, while the Mg-Sn alloys with higher Sn content (Sn≥3 wt.%) displayed α-Mg dendrites, and the secondary dendrite arm spacing of the primary α-Mg decreased significantly with increasing Sn content. The Mg-Sn alloys consisted of primary α-Mg matrix, Sn-rich segregation and Mg2Sn phase, and the amount of Mg2Sn phases increased with increasing Sn content. Potentiodynamic polarization and immersion tests revealed that the corrosion rates of Mg-Sn alloys increased with increasing Sn content. Cytotoxicity test showed that Mg-1Sn and Mg-3Sn alloys were harmless to MG63 cells. These results of the present study indicated that Mg-1Sn and Mg-3Sn alloys were promising to be used as biodegradable implants. Copyright © 2015 Elsevier B.V. All rights reserved.

SN Refsdal

DEFF Research Database (Denmark)

Kelly, P. L.; Brammer, G.; Selsing, J.

2016-01-01

(SNe), and we find strong evidence for a broad H-alpha P-Cygni profile in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show...... in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, SN Refsdal has a blue B-V color and a high luminosity for the assumed range of potential magnifications. If SN Refsdal can be modeled as a scaled version of SN...

A novel type heterojunction photodiodes formed junctions of Au/LiZnSnO and LiZnSnO/p-Si in series

Energy Technology Data Exchange (ETDEWEB)

Aydin, H. [Department of Metallurgical and Materials Science, Faculty of Engineering, Tunceli University, Tunceli (Turkey); Tataroğlu, A. [Department of Physics, Faculty of Science, Gazi University, Ankara (Turkey); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Yakuphanoglu, F., E-mail: fyhanoglu@firat.edu.tr [Department of Metallurgical and Materials Science, Faculty of Engineering, Tunceli University, Tunceli (Turkey); Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt); Farooq, W.A. [Physics and Astronomy Department, College of Science, King Saud University, Riyadh (Saudi Arabia)

2015-03-15

Highlights: • Lithium–zinc–tin–oxide thin films were prepared by sol gel method. • The Au/LiZnSnO/p-Si/Al photodiodes were fabricated using a LZTO layer grown on p-Si. • The photodiodes with Li-doped ZTO interfacial layer exhibited a better device performance. - Abstract: Lithium–zinc–tin–oxide thin films were prepared by sol gel method. The structural and optical properties of the films were investigated. The optical band gaps of the LiZnSnO films were found to be 3.78 eV for 0 at.% Li, 3.77 eV for 1 at.% Li, 3.87 eV for 3 at.% Li and 3.85 eV for 5 at.% Li, respectively. Au/LiZnSnO/p-Si/Al photodiodes were fabricated using a lithium–zinc–tin–oxide (LZTO, Li–Zn–Sn–O) layer grown on p-Si semiconductor. The electrical characteristics of the photodiodes were analyzed by current–voltage, capacitance–voltage and conductance–voltage measurements. The reverse current of the diodes increases with both the increasing illumination intensity and Li content. It was found that the Li-doped ZTO photodiodes exhibited a better device performance than those with an undoped ZTO.

Ab initio calculation of the electronic structure and spectroscopic properties of spinel γ-Sn3N4

International Nuclear Information System (INIS)

Ching, W. Y.; Rulis, Paul

2006-01-01

The electronic structure and physical properties of γ-Sn 3 N 4 in the spinel structure are investigated by first-principles calculations. The calculated band structure, electronic bonding, and optical properties are compared with two well-studied spinel nitrides γ-Si 3 N 4 and γ-Ge 3 N 4 . γ-Sn 3 N 4 is a semiconductor with a direct band gap of 1.40 eV and an attractive small electron effective mass of 0.17. Its optical properties are different from that of γ-Si 3 N 4 and γ-Ge 3 N 4 because of the difference in the conduction band minimum. The Sn K, Sn L 3 , Sn M 5 , and N K edges of the x-ray-absorption near-edge structure spectra in γ-Sn 3 N 4 are calculated using a supercell approach and are found to be rich in structures. These spectra are discussed in the context of the electronic structure of the unoccupied conduction band in the presence of the electron core-hole interaction. These calculated spectra can be used for the characterization of this novel compound

In-situ investigation of the order-disorder transition in Cu2ZnSnSe4 by optical transmission spectroscopy

Directory of Open Access Journals (Sweden)

Christiane Stroth

2017-02-01

Full Text Available The existence of disorder is one possible reason for the limited performance of kesterite solar cells. Therefore further knowledge of the order-disorder phase transition, of factors which influence the degree of order and of methods to determine this material property is still required. In this study we investigated the order-disorder transition in the kesterite material Cu2ZnSnSe4 by in-situ optical transmission spectroscopy during heat treatments. We show in-situ results for the temperature dependence of the band gap and its tailing properties. The influence of cooling rates on the phase transition was analyzed as well as the ordering kinetics during annealing at a constant temperature. The critical temperature of the phase transition was determined and the existence of a control temperature range is shown, which allows for controlling the degree of order by the cooling rate within this range. Additionally we performed Raman analysis to link Raman spectra to the degree of order in Cu2ZnSnSe4. A correlation between the intensity ratio of A-modes as well as B-/ E- Raman modes and the degree of order was found.

Above-bandgap optical properties of biaxially strained GeSn alloys grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Richard D’Costa, Vijay, E-mail: elevrd@nus.edu.sg; Wang, Wei; Zhou, Qian; Yeo, Yee-Chia, E-mail: eleyeoyc@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Soon Tok, Eng [Department of Physics, National University of Singapore, Singapore 117551 (Singapore)

2014-01-13

The complex dielectric function of biaxially strained Ge{sub 1−x}Sn{sub x} (0 ≤ x ≤ 0.17) alloys grown on Ge (100) has been determined by spectroscopic ellipsometry from 1.2 to 4.7 eV. The effect of substitutional Sn incorporation and the epitaxial strain on the energy transitions E{sub 1}, E{sub 1} + Δ{sub 1}, E{sub 0}′, and E{sub 2} of GeSn alloys is investigated. Our results indicate that the strained GeSn alloys show Ge-like electronic bandstructure with all the transitions shifted downward due to the alloying of Sn. The strain dependence of E{sub 1} and E{sub 1} + Δ{sub 1} transitions is explained using the deformation potential theory, and values of −5.4 ± 0.4 eV and 3.8 ± 0.5 eV are obtained for the hydrostatic and shear deformation potentials, respectively.

Electrical and optical studies in polyaniline nanofibre–SnO 2 ...

Indian Academy of Sciences (India)

Polyaniline nanofibre–tin oxide (PAni-SnO2) nanocomposites are synthesized and mixed with polyvinyl alcohol (PVA) as stabilizer to cast free-standing films. Composite films are characterized by X-ray diffraction studies (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ...

Quaternary chalcogenides La{sub 3}Sn{sub 0.5}InS{sub 7} and La{sub 3}Sn{sub 0.5}InSe{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Iyer, Abishek K.; Lee, Emma J.; Bernard, Guy M.; Michaelis, Vladimir K.; Mar, Arthur [Department of Chemistry, University of Alberta, Edmonton, AB (Canada); Yin, Wenlong [Department of Chemistry, University of Alberta, Edmonton, AB (Canada); Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang (China)

2017-12-13

The quaternary chalcogenides La{sub 3}Sn{sub 0.5}InS{sub 7} and La{sub 3}Sn{sub 0.5}InSe{sub 7} were prepared by reactions of the elements at 1050 C and 950 C, respectively. They adopt noncentrosymmetric structures [hexagonal, space group P6{sub 3}, Z = 2; a = 10.2993(11) Aa, c = 6.0921(6) Aa for La{sub 3}Sn{sub 0.5}InS{sub 7}; a = 10.6533(7) Aa, c = 6.4245(4) Aa for La{sub 3}Sn{sub 0.5}InSe{sub 7}] in which the half-occupancy of Sn atoms within octahedral sites classifies them as belonging to the La{sub 3}Mn{sub 0.5}SiS{sub 7}-type branch of the large family of quaternary rare-earth chalcogenides RE{sub 3}M{sub 1-x}M{sup '}Ch{sub 7}. The site distribution in La{sub 3}Sn{sub 0.5}InCh{sub 7}, with higher-valent Sn atoms occupying octahedral instead of tetrahedral sites, is reversed from the typical situation observed in other RE{sub 3}M{sub 1-x}M{sup '}Ch{sub 7} compounds. The ordered distribution of Sn atoms in octahedral sites and In atoms in tetrahedral sites was evaluated by bond valence sum analyses. Moreover, {sup 119}Sn solid-state nuclear magnetic resonance (NMR) spectroscopy confirms the occupation of Sn{sup 4+} species exclusively within octahedral sites. An optical bandgap of 1.45 eV was found for La{sub 3}Sn{sub 0.5}InS{sub 7}. Band structure calculations on an ordered superstructure model of La{sub 3}Sn{sub 0.5}InS{sub 7} reveal that avoidance of strongly Sn-S antibonding levels is an important driving force for the Sn deficiency. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lysophosphatidic Acid Acyltransferase from Coconut Endosperm Mediates the Insertion of Laurate at the sn-2 Position of Triacylglycerols in Lauric Rapeseed Oil and Can Increase Total Laurate Levels

Science.gov (United States)

Knutzon, Deborah S.; Hayes, Thomas R.; Wyrick, Annette; Xiong, Hui; Maelor Davies, H.; Voelker, Toni A.

1999-01-01

Expression of a California bay laurel (Umbellularia californica) 12:0-acyl-carrier protein thioesterase, bay thioesterase (BTE), in developing seeds of oilseed rape (Brassica napus) led to the production of oils containing up to 50% laurate. In these BTE oils, laurate is found almost exclusively at the sn-1 and sn-3 positions of the triacylglycerols (T.A. Voelker, T.R. Hayes, A.C. Cranmer, H.M. Davies [1996] Plant J 9: 229–241). Coexpression of a coconut (Cocos nucifera) 12:0-coenzyme A-preferring lysophosphatitic acid acyltransferase (D.S. Knutzon, K.D. Lardizabal, J.S. Nelsen, J.L. Bleibaum, H.M. Davies, J.G. Metz [1995] Plant Physiol 109: 999–1006) in BTE oilseed rape seeds facilitates efficient laurate deposition at the sn-2 position, resulting in the acccumulation of trilaurin. The introduction of the coconut protein into BTE oilseed rape lines with laurate above 50 mol % further increases total laurate levels. PMID:10398708

Wetting behaviour of lead-free Sn-based alloys on Cu and Ni substrates

International Nuclear Information System (INIS)

Amore, S.; Ricci, E.; Borzone, G.; Novakovic, R.

2008-01-01

The present work was carried out in the framework of the study of new lead-free solder alloys for technical applications in electronic devices. In the focus of this characterisation the wetting behaviour of several Sn-rich alloys belonging to the In-Sn, Au-Sn and Cu-Sn systems has been studied by measuring the contact angle variations on Cu and Ni substrates as a function of time and temperature. The interface between the alloy and the substrate has been analysed by the use of optical microscopy and scanning electron microscopy combined with energy-dispersive X-ray spectrometry in order to study the reaction between the alloy and the solid substrate and the possible formation of different compounds at the interface. A remarkable effect of the two different substrates on the behaviour of the contact angle as a function of temperature and on the morphology of the interface between the liquid solder and the solid substrate was observed for the In-Sn and Cu-Sn, while the Au-Sn system shows a very similar wetting behaviour on Cu and Ni

Modifications in SnS thin films by plasma treatments

Energy Technology Data Exchange (ETDEWEB)

Martinez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Avellaneda, D. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico)

2012-02-01

The present study shows the modifications of structural, optical and electrical characteristics that occur in tin sulfide (SnS) thin films treated in air and in nitrogen plasma at different pressure conditions. The films were obtained by the chemical bath deposition method, which results in SnS thin films with an orthorhombic crystalline structure, band gap (E{sub g}) of 1.1-1.2 eV, and electrical conductivities ({sigma}) in the order of 10{sup -6} {Omega}{sup -1}cm{sup -1}. The films treated with air plasma at pressures between 1 and 4 Torr, showed the presence of SnS{sub 2}, Sn{sub 2}S{sub 3}, and SnO{sub 2} phases, within the band gap values ranging from 0.9 to 1.5 eV. On the other hand, the films treated with nitrogen plasma presented the same phases, but showed a significant modification in the electrical conductivity, increasing from 10{sup -6} {Omega}{sup -1}cm{sup -1} (as-deposited) up to 10{sup -2}-10{sup -3} {Omega}{sup -1}cm{sup -1} (plasma treated). This result is a suitable range of conductivity for the improvement of the solar cells with SnS as an absorber material. Also, emission spectroscopy measurements were carried out in both air and nitrogen plasma treatments.

The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

Energy Technology Data Exchange (ETDEWEB)

Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

2008-02-15

The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

Optical, Near-IR, and X-Ray Observations of SN 2015J and Its Host Galaxy

Science.gov (United States)

Nucita, A. A.; De Paolis, F.; Saxton, R.; Testa, V.; Strafella, F.; Read, A.; Licchelli, D.; Ingrosso, G.; Convenga, F.; Boutsia, K.

2017-12-01

SN 2015J was discovered on 2015 April 27th and is classified as an SN IIn. At first, it appeared to be an orphan SN candidate, I.e., without any clear identification of its host galaxy. Here, we present an analysis of the observations carried out by the VLT 8 m class telescope with the FORS2 camera in the R band and the Magellan telescope (6.5 m) equipped with the IMACS Short-Camera (V and I filters) and the FourStar camera (Ks filter). We show that SN 2015J resides in what appears to be a very compact galaxy, establishing a relation between the SN event and its natural host. We also present and discuss archival and new X-ray data centered on SN 2015J. At the time of the supernova explosion, Swift/XRT observations were made and a weak X-ray source was detected at the location of SN 2015J. Almost one year later, the same source was unambiguously identified during serendipitous observations by Swift/XRT and XMM-Newton, clearly showing an enhancement of the 0.3-10 keV band flux by a factor ≃ 30 with respect to the initial state. Swift/XRT observations show that the source is still active in the X-rays at a level of ≃ 0.05 counts s-1. The unabsorbed X-ray luminosity derived from the XMM-Newton slew and SWIFT observations, {L}x≃ 5× {10}41 erg s-1, places SN 2015J among the brightest young supernovae in X-rays. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA, with ESO Telescopes at the La Silla-Paranal Observatory under program ID 298.D-5016(A), and with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. We also acknowledge the use of public data from the Swift data archive.

Study of Sb/SnO{sub 2} bi-layer films prepared by ion beam sputtering deposition technique

Energy Technology Data Exchange (ETDEWEB)

Wang, Chun-Min [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Huang, Chun-Chieh [Department of Electrical Engineering, Cheng Shiu University, No. 840, Chengcing Road, Niaosong Township, Kaohsiung 833, Taiwan, ROC (China); Kuo, Jui-Chao [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Huang, Jow-Lay, E-mail: jlh888@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan, ROC (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

2014-11-03

In the present work, bi-layer thin films of Sb/SnO{sub 2} were produced on unheated glass substrates using ion beam sputtering (IBS) technique without post annealing treatment. The thickness of Sb layers was varied from 2 to 10 nm and the Sb layers were deposited on SnO{sub 2} layers having thicknesses of 40 nm to 115 nm. The effect of thickness was studied on the morphological, electrical and optical properties. The Sb/SnO{sub 2} bi-layer resulted in lowering the electrical resistivity as well as reducing the optical transmittance. However, the optical and electrical properties of the bi-layer films were mainly influenced by the thickness of Sb layers due to progressive transfer in structures from aggregate to continuous films. The bi-layer films show the electrical resistivity of 1.4 × 10{sup −3} Ω cm and an optical transmittance of 26% for Sb film having 10 nm thickness. - Highlights: • Bi-layer Sb/SnO{sub 2} structures were synthesized by ion beam sputtering (IBS) technique. • The 6 nm-thick Sb film is a transition region in this study. • The conductivity of the bi-layer films is increased as Sb thickness increases. • The transmittance of the bi-layer films is decreased as Sb thickness increases.

Near-infrared light absorption by polycrystalline SiSn alloys grown on insulating layers

Energy Technology Data Exchange (ETDEWEB)

Kurosawa, Masashi, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); JSPS, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Kato, Motohiro; Yamaha, Takashi; Taoka, Noriyuki; Nakatsuka, Osamu [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Zaima, Shigeaki [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2015-04-27

High-Sn-content SiSn alloys are strongly desired for the next-generation near-infrared optoelectronics. A polycrystalline growth study has been conducted on amorphous SiSn layers with a Sn-content of 2%–30% deposited on either a substrate of SiO{sub 2} or SiN. Incorporating 30% Sn into Si permits the crystallization of the amorphous layers at annealing temperatures below the melting point of Sn (231.9 °C). Composition analyses indicate that approximately 20% of the Sn atoms are substituted into the Si lattice after solid-phase crystallization at 150–220 °C for 5 h. Correspondingly, the optical absorption edge is red-shifted from 1.12 eV (Si) to 0.83 eV (Si{sub 1−x}Sn{sub x} (x ≈ 0.18 ± 0.04)), and the difference between the indirect and direct band gap is significantly reduced from 3.1 eV (Si) to 0.22 eV (Si{sub 1−x}Sn{sub x} (x ≈ 0.18 ± 0.04)). These results suggest that with higher substitutional Sn content the SiSn alloys could become a direct band-gap material, which would provide benefits for Si photonics.

Synthesis and characterization of thermally evaporated Cu2SnSe3 ternary semiconductor

Science.gov (United States)

Hamdani, K.; Chaouche, M.; Benabdeslem, M.; Bechiri, L.; Benslim, N.; Amara, A.; Portier, X.; Bououdina, M.; Otmani, A.; Marie, P.

2014-11-01

Copper Tin Selenide (CuSnSe) powder was mechanically alloyed by high energy planetary ball milling, starting from elemental powders. Synthesis time and velocity have been optimized to produce Cu2SnSe3 materials. Thin films were prepared by thermal evaporation on Corning glass substrate at Ts = 300 °C. The structural, compositional, morphological and optical properties of the synthesized semiconductor have been analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and transmission electron microscopy. The analyzed powder exhibited a cubic crystal structure, with the presence of Cu2Se as a secondary phase. On the other hand, the deposited films showed a cubic Cu2SnSe3 ternary phase and extra peaks belonging to some binary compounds. Furthermore, optical measurements showed that the deposited layers have a relatively high absorption coefficient of 105 cm-1 and present a band gap of 0.94 eV.

Temperature dependent growth and optical properties of SnO2 ...

Indian Academy of Sciences (India)

Administrator

SEM micrographs of SnO2 nanowires and a single nanowire of diameter 50–60 .... the size of the nanoparti- cles may control the thickness and morphology of resul- ... from the analysis of peak shapes and the selection rules. XRD and electron ...

Degradation mechanism of Nb3Sn composite wires under tensile strain at 4.2 K

International Nuclear Information System (INIS)

Luhman, T.; Suenaga, M.; Welch, D.O.; Kaiho, K.

1978-01-01

Bronze-processed Nb 3 Sn composite wire conductors exhibit changes in their superconducting parameters when strained in tension. This paper describes a detailed study of the effect of strain on critical current and an analysis by optical and SEM techniques of crack formation in the Nb 3 Sn layer under strain. The effect of strain history on both reversible and irreversible changes in critical current and the roles of differential thermal contraction induced residual strains and of Nb 3 Sn cracking are discussed

Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A

Energy Technology Data Exchange (ETDEWEB)

McCully, Curtis; Jha, Saurabh W. [Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Foley, Ryan J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Chornock, Ryan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Holtzman, Jon A. [Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States); Balam, David D. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Branch, David [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Frieman, Joshua [Kavli Institute for Cosmological Physics and Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Fynbo, Johan; Leloudas, Giorgos [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Galbany, Lluis [Institut de Física d' Altes Energies, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Garnavich, Peter M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Graham, Melissa L. [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Leonard, Douglas C., E-mail: cmccully@physics.rutgers.edu [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); and others

2014-05-10

We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are observed in other SNe at late phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I more than a year past maximum light, along with narrow [Fe II] and [Ca II] emission. We use spectral features to constrain the temperature and density of the ejecta, and find high densities at late times, with n{sub e} ≳ 10{sup 9} cm{sup –3}. Such high densities should yield enhanced cooling of the ejecta, making these objects good candidates to observe the expected 'infrared catastrophe', a generic feature of SN Ia models. However, our HST photometry of SN 2008A does not match the predictions of an infrared catastrophe. Moreover, our HST observations rule out a 'complete deflagration' that fully disrupts the white dwarf for these peculiar SNe, showing no evidence for unburned material at late times. Deflagration explosion models that leave behind a bound remnant can match some of the observed properties of SNe Iax, but no published model is consistent with all of our observations of SNe 2005hk and 2008A.

Hubble space telescope and ground-based observations of the type Iax supernovae SN 2005hk and SN 2008A

International Nuclear Information System (INIS)

McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Chornock, Ryan; Holtzman, Jon A.; Balam, David D.; Branch, David; Filippenko, Alexei V.; Ganeshalingam, Mohan; Li, Weidong; Frieman, Joshua; Fynbo, Johan; Leloudas, Giorgos; Galbany, Lluis; Garnavich, Peter M.; Graham, Melissa L.; Hsiao, Eric Y.; Leonard, Douglas C.

2014-01-01

We present Hubble Space Telescope (HST) and ground-based optical and near-infrared observations of SN 2005hk and SN 2008A, typical members of the Type Iax class of supernovae (SNe). Here we focus on late-time observations, where these objects deviate most dramatically from all other SN types. Instead of the dominant nebular emission lines that are observed in other SNe at late phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I more than a year past maximum light, along with narrow [Fe II] and [Ca II] emission. We use spectral features to constrain the temperature and density of the ejecta, and find high densities at late times, with n e ≳ 10 9 cm –3 . Such high densities should yield enhanced cooling of the ejecta, making these objects good candidates to observe the expected 'infrared catastrophe', a generic feature of SN Ia models. However, our HST photometry of SN 2008A does not match the predictions of an infrared catastrophe. Moreover, our HST observations rule out a 'complete deflagration' that fully disrupts the white dwarf for these peculiar SNe, showing no evidence for unburned material at late times. Deflagration explosion models that leave behind a bound remnant can match some of the observed properties of SNe Iax, but no published model is consistent with all of our observations of SNe 2005hk and 2008A.

Cu2SixSn1-xS3 Thin Films Prepared by Reactive Magnetron Sputtering For Low-Cost Thin Film Solar Cells

Science.gov (United States)

Yan, Chang; Liu, Fang-Yang; Lai, Yan-Qing; Li, Jie; Liu, Ye-Xiang

2011-10-01

We report the preparation of Cu2SixSn1-xS3 thin films for thin film solar cell absorbers using the reactive magnetron co-sputtering technique. Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu2Si1-xSnxS3 thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu2SnS3 lattice, leading to a shrinkage of the lattice, and, accordingly, by 2θ shifting to larger values. The blue shift of the Raman peak further confirms the formation of Cu2SixSn1-xS3. Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200-300 nm. Optical measurements indicate an optical absorption coefficient of higher than 104 cm-1 and an optical bandgap of 1.17±0.01 eV.

Docosahexaenoic acid (DHA) at the sn-2 position of triacylglycerols increases DHA incorporation in brown, but not in white adipose tissue, of hamsters.

Science.gov (United States)

Lopes, Paula A; Bandarra, Narcisa M; Martins, Susana V; Madeira, Marta S; Ferreira, Júlia; Guil-Guerrero, José L; Prates, José A M

2018-06-01

We hypothesised that the incorporation of docosahexaenoic acid (DHA) across adipose tissues will be higher when it is ingested as triacylglycerols (TAG) structured at the sn-2 position. Ten-week old male hamsters were allocated to 4 dietary treatments (n = 10): linseed oil (LSO-control group), fish oil (FO), fish oil ethyl esters (FO-EE) and structured DHA at the sn-2 position of TAG (DHA-SL) during 12 weeks. In opposition to the large variations found for fatty acid composition in retroperitoneal white adipose tissue (WAT), brown adipose tissue (BAT) was less responsive to diets. DHA was not found in subcutaneous and retroperitoneal WAT depots but it was successfully incorporated in BAT reaching the highest percentage in DHA-SL. The PCA on plasma hormones (insulin, leptin, adiponectin) and fatty acids discriminated BAT from WATs pointing towards an individual signature on fatty acid deposition, but did not allow for full discrimination of dietary treatments within each adipose tissue.

Sn2+—Stabilization in MASnI3 perovskites by superhalide incorporation

Science.gov (United States)

Xiang, Junxiang; Wang, Kan; Xiang, Bin; Cui, Xudong

2018-03-01

Sn-based hybrid halide perovskites are a potential solution to replace Pb and thereby reduce Pb toxicity in MAPbI3 perovskite-based solar cells. However, the instability of Sn2+ in air atmosphere causes a poor reproducibility of MASnI3, hindering steps towards this goal. In this paper, we propose a new type of organic metal-superhalide perovskite of MASnI2BH4 and MASnI2AlH4. Through first-principles calculations, our results reveal that the incorporation of BH4 and AlH4 superhalides can realize an impressive enhancement of oxidation resistance of Sn2+ in MASnI3 perovskites because of the large electron transfer between Sn2+ and [BH4]-/[AlH4]-. Meanwhile, the high carrier mobility is preserved in these superhalide perovskites and only a slight decrease is observed in the optical absorption strength. Our studies provide a new path to attain highly stable performance and reproducibility of Sn-based perovskite solar cells.

Sites of Au atoms in Sn crystals as determined by channeling

International Nuclear Information System (INIS)

Miller, J.W.; Gemmell, D.S.; Holland, R.E.; Poizat, J.C.; Worthington, J.N.; Loess, R.E.

1974-01-01

The position of Au atoms diffused into Sn monocrystals has been studied by channeling and backscattering of 2.5-MeV Ne ions. For equilibrium conditions at 217 0 C, Au atoms are found almost entirely in substitutional positions, so that the unusually fast diffusion of Au in Sn most likely arises from a small fraction of Au atoms migrating interstitially

Position and width of normal adult optic chiasm as measured in coronal MRI

International Nuclear Information System (INIS)

Kim, Myung Soon; Park, Jin Sook

1994-01-01

To evaluate the position and transverse dimension of the adult optic chiasm in normal Korean adult. The authors analysed 3D coronal volume images (TR/TE=30/13, flip angle=30 .deg. ) of 136 normal adult subjects without known visual abnormality. All MRI examinations were performed using a 0.5T system. MRI was reviewed retrospectively to determine the position (horizontal and tilted) of the potic chiosm and the transverse dimension of the optic chiasm was measured. Seventy- five (55%) of the 136 normal subjects had horizontal position, and sixty-one (45%) had tilted position. Thirty- eight (62%) of 61 with tilted position showed higher position on the right side, and twenty-three (38%) showed higher position on the side. The average transverse dimension(mean SD) was 15.2 ± 0.7mm in men and 14.6 ± 1.0mm in women. The difference of transverse dimension between men and women was statistically significant. Tilted position of the adult optic chiasm on coronal MRI was seen in approximately half of normal adults. The average of transverse dimension of normal optic chiasm was 15mm

Reference Data for the Density, Viscosity, and Surface Tension of Liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn Eutectic Alloys

Science.gov (United States)

Dobosz, Alexandra; Gancarz, Tomasz

2018-03-01

The data for the physicochemical properties viscosity, density, and surface tension obtained by different experimental techniques have been analyzed for liquid Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn eutectic alloys. All experimental data sets have been categorized and described by the year of publication, the technique used to obtain the data, the purity of the samples and their compositions, the quoted uncertainty, the number of data in the data set, the form of data, and the temperature range. The proposed standard deviations of liquid eutectic Al-Zn, Ag-Sn, Bi-Sn, Cu-Sn, and Sn-Zn alloys are 0.8%, 0.1%, 0.5%, 0.2%, and 0.1% for the density, 8.7%, 4.1%, 3.6%, 5.1%, and 4.0% for viscosity, and 1.0%, 0.5%, 0.3%, N/A, and 0.4% for surface tension, respectively, at a confidence level of 95%.

The Structural Changes of the Sn(y)OX Thin Films Under Influence of Heat Treament

Science.gov (United States)

Vong, V.

2001-04-01

Composite oxide Sn(y) Ox made by thermal oxidation of the Sn(y)-bimetal thin films, in which y is the doped-materials as well as Sb, Ag or Pd. The Sn(y)-bimetal thin films have been made by evaporation in high vacuum onto NaCl-monocrystall and optical glass substrates. In the work the tin and the doped material (y) were put on two different boats and then both the boats were simultaniously heated to evaporate. The Sn(y)Ox thin films were annealed at the differential temperatures. The structural changes of its have been investigated by using X-ray diffraction and transmission electron microscope.

On possibility of superconductivity in SnSb: A first principle study

Energy Technology Data Exchange (ETDEWEB)

Dabhi, Shweta D. [Department of Physics, M. K. Bhavnagar University, Bhavnagar 364001 (India); Shrivastava, Deepika [Department of Physics, Barkatullah University, Bhopal 462026 (India); Jha, Prafulla K., E-mail: prafullaj@yahoo.com [Department of Physics, Faculty of Science, The M. S. University of Baroda, Vadodara 390002 (India); Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

2016-09-15

Highlights: • Superconducting property of SnSb is predicted by ab-initio calculations. • Electronic properties of SnSb in RS phase shows metallic behaviour similar to SnAs. • Phonon dispersion confirms the dynamical stability of SnSb in RS phase. • Superconducting transition temperature is 3.1 K, slightly lower than that of SnAs. • Calculated thermodynamic properties are also reported. - Abstract: The electronic, phonon structure and superconducting properties of tin antimonide (SnSb) in rock-salt (RS) structure are calculated using first-principles density functional theory. The electronic band structure and density of states show metallic behavior. The phonon frequencies are positive throughout the Brillouin zone in rock-salt structure indicating its stability in that phase. Superconductivity of SnSb in RS phase is discussed in detail by calculating phonon linewidths, Eliashberg spectral function, electron-phonon coupling constant and superconducting transition temperature. SnSb is found to have a slightly lower T{sub C} (3.1 K), as compared to SnAs.

An investigation of the Nb doping effect on structural, morphological, electrical and optical properties of spray deposited F doped SnO2 films

Science.gov (United States)

Turgut, G.; Keskenler, E. F.; Aydın, S.; Yılmaz, M.; Doǧan, S.; Düzgün, B.

2013-03-01

F and Nb + F co-doped SnO2 thin films were deposited on glass substrates by the spray pyrolysis method. The microstructural, morphological, electrical and optical properties of the 10 wt% F doped SnO2 (FTO) thin films were investigated specifically for niobium (Nb) doping in the range of 0-4 at.% with 1 at.% steps. As shown by the x-ray diffraction patterns, the films exhibited a tetragonal cassiterite structure with (200) preferential orientation. It was observed that grain sizes of the films for (200) and (301) peaks depended on the Nb doping concentration and varied in the range of 25.11-32.19 and 100.6-183.7 nm, respectively. The scanning electron microscope (SEM) micrographs showed that the FTO films were made of small pyramidal grains, while doubly doped films were made of small pyramidal grains and big polyhedron grains. From electrical studies, although 1 at.% Nb doped FTO films have the lowest sheet resistance and resistivity values, the highest figure-of-merit and optical band gap values obtained for FTO films were 16.2 × 10-2 Ω-1 and 4.21 eV, respectively. Also, infrared reflectivity values of the films were in the range of 97.39-98.98%. These results strongly suggest that these films are an attractive candidate for various optoelectronic applications and for photothermal conversion of solar energy.

Structural, optical and dielectric properties of Sn0.97Ce0.03O2 nanostructures

Science.gov (United States)

Ahmed, Ateeq; Siddique, M. Naseem; Ali, Tinku; Tripathi, P.

2018-05-01

In present work, 3% cerium doped SnO2 (Sn0.97Ce0.03O2) nanoparticles (NPs) have been synthesized by sol-gel method. The prepared sample has been characterized by using various techniques such as XRD, UV-visible absorption spectroscopy and LCR meter measurements. Structural Rietveld refinement of XRD data reveals that (Sn0.97Ce0.03O2) sample has a pure single phase tetragonal structure with space group (P42/mnm) without creating any impurity phase such as cerium oxide. UV-visible spectroscopy determines band gap value 3.47 eV for (Sn0.97Ce0.03O2) NPs using Tauc's relation. Dielectric constant and loss decreased with increase in frequency while ac conductivity was found to increase with increase in frequency. The observed dielectric results has been explained in the light of Maxwell-Wagner model.

Swift heavy ion irradiated SnO{sub 2} thin film sensor for efficient detection of SO{sub 2} gas

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Punit; Sharma, Savita [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Department of Physics, Miranda House, University of Delhi, Delhi 110007 (India); Singh, Fouran [Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2016-07-15

Highlights: • Response of Ni{sup 7+} ion irradiated (100 MeV) SnO{sub 2} film have been performed. • Effect of irradiation on the structural and optical properties of SnO{sub 2} film is studied. • A decrease in operating temperature and increased response is seen after irradiation. - Abstract: Gas sensing response studies of the Ni{sup 7+} ion irradiated (100 MeV) and non-irradiated SnO{sub 2} thin film sensor prepared under same conditions have been performed towards SO{sub 2} gas (500 ppm). The effect of irradiation on the structural, surface morphological, optical and gas sensing properties of SnO{sub 2} thin film based sensor have been studied. A significant decrease in operating temperature (from 220 °C to 60 °C) and increased sensing response (from 1.3 to 5.0) is observed for the sample after irradiation. The enhanced sensing response obtained for the irradiated SnO{sub 2} thin film based sensor is attributed to the desired modification in the surface morphology and material properties of SnO{sub 2} thin film by Ni{sup 7+} ions.

Linearization of Positional Response Curve of a Fiber-optic Displacement Sensor

Science.gov (United States)

Babaev, O. G.; Matyunin, S. A.; Paranin, V. D.

2018-01-01

Currently, the creation of optical measuring instruments and sensors for measuring linear displacement is one of the most relevant problems in the area of instrumentation. Fiber-optic contactless sensors based on the magneto-optical effect are of special interest. They are essentially contactless, non-electrical and have a closed optical channel not subject to contamination. The main problem of this type of sensors is the non-linearity of their positional response curve due to the hyperbolic nature of the magnetic field intensity variation induced by moving the magnetic source mounted on the controlled object relative to the sensing element. This paper discusses an algorithmic method of linearizing the positional response curve of fiber-optic displacement sensors in any selected range of the displacements to be measured. The method is divided into two stages: 1 - definition of the calibration function, 2 - measurement and linearization of the positional response curve (including its temperature stabilization). The algorithm under consideration significantly reduces the number of points of the calibration function, which is essential for the calibration of temperature dependence, due to the use of the points that randomly deviate from the grid points with uniform spacing. Subsequent interpolation of the deviating points and piecewise linear-plane approximation of the calibration function reduces the microcontroller storage capacity for storing the calibration function and the time required to process the measurement results. The paper also presents experimental results of testing real samples of fiber-optic displacement sensors.

Review of sn-2 palmitate oil implications for infant health.

Science.gov (United States)

Bar-Yoseph, Fabiana; Lifshitz, Yael; Cohen, Tzafra

2013-09-01

Human milk provides the optimal balanced nutrition for the growing infant in the first months after birth. The human mammary gland has evolved with unusual pathways, resulting in a specific positioning of fatty acids at the outer sn-1 and sn-3, and center sn-2 of the triacylglyceride, which is different from the triglycerides in other human tissues and plasma. The development of structured triglycerides enables mimicking the composition as well as structure of human milk fat in infant formulas. Studies conducted two decades ago, together with very recent studies, have provided increasing evidence that this unusual positioning of 16:0 in human milk triglycerides has a significant role for infant health in different directions, such as fat and calcium absorption, bone health, intestinal flora and infant comfort. This review aims to unravel the relevance of human milk triglyceride sn-2 16:0 for intestinal health and inflammatory pathways and for other post-absorption effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

Detection of Sn(II) ions via quenching of the fluorescence of carbon nanodots

International Nuclear Information System (INIS)

Mohd Yazid, S.N.A.; Chin, S.F.; Pang, S.C.; Ng, S.M.

2013-01-01

We report that fluorescent carbon nanodots (C-dots) can act as an optical probe for quantifying Sn(II) ions in aqueous solution. C-dots are synthesized by carbonization and surface oxidation of preformed sago starch nanoparticles. Their fluorescence is significantly quenched by Sn(II) ions, and the effect can be used to determine Sn(II) ions. The highest fluorescence intensity is obtained at a concentration of 1.75 mM of C-dots in aqueous solution. The probe is highly selective and hardly interfered by other ions. The quenching mechanism appears to be predominantly of the static (rather than dynamic) type. Under optimum conditions, there is a linear relationship between fluorescence intensity and Sn(II) ions concentration up to 4 mM, and with a detection limit of 0.36 μM. (author)

The peculiar balmer decrement of SN 2009ip: Constraints on circumstellar geometry

Energy Technology Data Exchange (ETDEWEB)

Levesque, Emily M.; Stringfellow, Guy S.; Bally, John; Keeney, Brian A. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Ginsburg, Adam G., E-mail: Emily.Levesque@colorado.edu [European Southern Observatory, ESO Headquarters, Karl-Schwarzschild-Strasse 2, D-95748 Garching bei München (Germany)

2014-01-01

We present optical and near-IR spectroscopic observations of the luminous blue variable SN 2009ip during its remarkable photometric evolution of 2012. The spectra sample three key points in the SN 2009ip light curve, corresponding to its initial brightening in August (2012-A) and its dramatic rebrightening in early October (2012-B). Based on line fluxes and velocities measured in our spectra, we find a surprisingly low I(Hα)/I(Hβ) ratio (∼1.3-1.4) in the 2012-B spectra. Such a ratio implies either a rare Case B recombination scenario where Hα, but not Hβ, is optically thick, or an extremely high density for the circumstellar material of n{sub e} > 10{sup 13} cm{sup –3}. The Hα line intensity yields a minimum radiating surface area of ≳20,000 AU{sup 2} in Hα at the peak of SN 2009ip's photometric evolution. Combined with the nature of this object's spectral evolution in 2012, a high circumstellar density and large radiating surface area imply the presence of a thin disk geometry around the central star (and, consequently, a possible binary companion), suggesting that the observed 2012-B rebrightening of SN 2009ip can be attributed to the illumination of the disk's inner rim by fast-moving ejecta produced by the underlying events of 2012-A.

Preparation and characterization of Cu2SnS3 thin films by electrodeposition

Science.gov (United States)

Patel, Biren; Narasimman, R.; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit

2018-05-01

Cu2SnS3 thin films were electrodeposited on F:SnO2/Glass substrates at room temperature by using aqueous solution. Copper and tin were first electrodeposited from single bath and post annealed in the presence of sulphur atmosphere to obtain the Cu2SnS3 phase. The Cu2SnS3 phase with preferred orientation along the (112) crystal direction grows to greater extent by the post annealing of the film. Raman analysis confirms the monoclinic crystal structure of Cu2SnS3 with principle mode of vibration as A1 (symmetric breathing mode) corresponding to the band at 291 cm-1. It also reveals the benign coexistence of orthorhombic Cu3SnS4 and Cu2SnS7 phases. Optical properties of the film show direct band gap of 1.25 eV with a high absorption coefficient of the order of 104 cm-1 in the visible region. Photo activity of the electrodeposited film was established in two electrode photoelectro-chemical cell, where an open circuit voltage of 91.6 mV and a short circuit current density of 10.6 µA/cm2 were recorded. Fabrication of Cu2SnS3 thin film heterojunction solar cell is underway.

Supernova 2008J: early time observations of a heavily reddened SN 2002ic-like transient

DEFF Research Database (Denmark)

Taddia, F.; Stritzinger, M. D.; Phillips, M. M.

2012-01-01

Aims: We provide additional observational evidence that some Type Ia supernovae (SNe Ia) show signatures of circumstellar interaction (CSI) with hydrogen-rich material. Methods: Early phase optical and near-infrared (NIR) light curves and spectroscopy of SN 2008J obtained by the Carnegie Supernova...... that their CSI emissions are similarly robust. The high-resolution spectrum reveals narrow emission lines produced from un-shocked gas characterized by a wind velocity of ~50 km s-1. We conclude that SN 2008J best matches an explosion of a SN Ia that interacts with its CSM....

Electron beam position stabilization with a piezo-electric optical correction system

CERN Document Server

Averett, T; McKeown, R D; Pitt, M

1999-01-01

A piezo-electrically controlled optical correction system was successfully used to reduce the helicity-correlated pulse-to-pulse position differences of a laser spot to better than +-100 nm at a pulse rate of 600 Hz. Using a simple feedback algorithm, average position differences of DELTA x-bar=-3.5+-4.2 nm and DELTA y-bar=2.6+-6.6 nm were obtained over a 6 h period. This optical correction system was successfully used in the polarized electron source at the Bates Linear Accelerator Center to stabilize the position of the electron beam during the recent SAMPLE experiment. Because this experiment measures a parity violating signal at the 10 sup - sup 6 level, it is sensitive to systematic effects which are correlated with the helicity of the incident electrons. One potentially large systematic effect is the helicity-correlated motion of the incident electron beam. By using this optical correction system, electron beam position differences at the location of the experiment were routinely kept well below +-100 n...

Growth Structural and Optical Properties of the Thermally Evaporated Tin Diselenide (SnSe2) Thin Films

OpenAIRE

R. Sachdeva1,; M. Sharma1,; A. Devi1,; U. Parihar1,; N. Kumar1,; N. Padha1,; C.J. Panchal

2011-01-01

Tin diselenide (SnSe2) compound was prepared by melt-quenching technique from its constituent elements. The phase structure and composition of the chemical constituents present in the bulk has been determined using X-ray diffraction (XRD) and energy dispersion X-ray analysis (EDAX) respectively. SnSe2 thin films were grown using direct thermal evaporation of SnSe2 compound material on chemically cleaned glass substrate, which were held at different substrate temperatures. X-ray diffraction an...

Extreme IR absorption in group IV-SiGeSn core-shell nanowires

Science.gov (United States)

Attiaoui, Anis; Wirth, Stephan; Blanchard-Dionne, André-Pierre; Meunier, Michel; Hartmann, J. M.; Buca, Dan; Moutanabbir, Oussama

2018-06-01

Sn-containing Si and Ge (Ge1-y-xSixSny) alloys are an emerging family of semiconductors with the potential to impact group IV material-based devices. These semiconductors provide the ability to independently engineer both the lattice parameter and bandgap, which holds the premise to develop enhanced or novel photonic and electronic devices. With this perspective, we present detailed investigations of the influence of Ge1-y-xSixSny layers on the optical properties of Si and Ge based heterostructures and nanowires. We found that by adding a thin Ge1-y-xSixSny capping layer on Si or Ge greatly enhances light absorption especially in the near infrared range, leading to an increase in short-circuit current density. For the Ge1-y-xSixSny structure at thicknesses below 30 nm, a 14-fold increase in the short-circuit current is observed with respect to bare Si. This enhancement decreases by reducing the capping layer thickness. Conversely, decreasing the shell thickness was found to improve the short-circuit current in Si/Ge1-y-xSixSny and Ge/Ge1-y-xSixSny core/shell nanowires. The optical absorption becomes very important by increasing the Sn content. Moreover, by exploiting an optical antenna effect, these nanowires show extreme light absorption, reaching an enhancement factor, with respect to Si or Ge nanowires, on the order of 104 in Si/Ge0.84Si0.04Sn0.12 and 12 in Ge/Ge0.84Si0.04Sn0.12. Furthermore, we analyzed the optical response after the addition of a dielectric layer of Si3N4 to the Si/Ge1-y-xSixSny core-shell nanowire and found approximatively a 50% increase in the short-circuit current density for a dielectric layer of thickness equal to 45 nm and both a core radius and a shell thickness greater than 40 nm. The core-shell optical antenna benefits from a multiplication of enhancements contributed by leaky mode resonances in the semiconductor part and antireflection effects in the dielectric part.

Application of sol-gel process on the elaboration of SnO2 based ceramics

International Nuclear Information System (INIS)

Prescatan, R.T.; Silva, D.V. da; Hiratsuka, R.S.; Santilli, C.V.; Pulcinelli, S.H.

1990-01-01

The electrical, optical and chemical peculiar properties of SnO 2 confers it-self some potential application. The densification difficulty during sintering of SnO 2 compromises its elaboration by ceramic conventional process. In this work the preparation of SnO 2 ceramics by sol-gel process was investigated. Some parameters envolved on the colloidal stability, sol-gel transition and drying process were analysed. The obtained materials were characterized by rheological, X-ray diffraction, infra-red spectroscopy and pores size distribution measurements. The results show that a considerable densification during sintering at 400 and 600 0 C was obtained. (author) [pt

Disorder-induced enhancement of indirect absorption in a GeSn photodetector grown by molecular beam epitaxy

International Nuclear Information System (INIS)

Li, H.; Chang, C.; Cheng, H. H.; Sun, G.; Soref, R. A.

2016-01-01

We report an investigation on the absorption mechanism of a GeSn photodetector with 2.4% Sn composition in the active region. Responsivity is measured and absorption coefficient is calculated. Square root of absorption coefficient linearly depends on photon energy indicating an indirect transition. However, the absorption coefficient is found to be at least one order of magnitude higher than that of most other indirect materials, suggesting that the indirect optical absorption transition cannot be assisted only by phonon. Our analysis of absorption measurements by other groups on the same material system showed the values of absorption coefficient on the same order of magnitude. Our study reveals that the strong enhancement of absorption for the indirect optical transition is the result of alloy disorder from the incorporation of the much larger Sn atoms into the Ge lattice that are randomly distributed.

Investigation on structural, surface morphological and dielectric properties of Zn-doped SnO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sagadevan, Suresh [Department of Physics, AMET University, Chennai (India); Podder, Jiban, E-mail: sureshsagadevan@gmail.com [Department of Chemical and Biological Engineering, University of Saskatchewan (Canada)

2016-03-15

Zinc doped Tin oxide (SnO{sub 2}) nanoparticles were prepared by co-precipitation method. The average crystallite size of pure and Zn-doped SnO{sub 2} nanoparticles was calculated from the X-ray diffraction (XRD) pattern. The FT-IR spectrum indicated the strong presence of SnO{sub 2} nanoparticles. The morphology and the particle size were studied using the scanning electron microscope (SEM) and transmission electron microscope (TEM). The particle size of the Zn-doped SnO{sub 2} nanoparticles was also analyzed, using the Dynamic Light Scattering (DLS) experiment. The optical properties were studied by the UV-Visible absorption spectrum. The dielectric properties of Zn-doped SnO{sub 2} nanoparticles were studied at different frequencies and temperatures. The ac conductivity of Zn-doped SnO{sub 2} nanoparticles was also studied. (author)

La5Zn2Sn

Directory of Open Access Journals (Sweden)

Igor Oshchapovsky

2011-11-01

Full Text Available A single crystal of pentalanthanum dizinc stannide, La5Zn2Sn, was obtained from the elements in a resistance furnace. It belongs to the Mo5SiB2 structure type, which is a ternary ordered variant of the Cr5B3 structure type. The space is filled by bicapped tetragonal antiprisms from lanthanum atoms around tin atoms sharing their vertices. Zinc atoms fill voids between these bicapped tetragonal antiprisms. All four atoms in the asymmetric unit reside on special positions with the following site symmetries: La1 (..m; La2 (4/m..; Zn (m.2m; Sn (422.

Annealing of RF-magnetron sputtered SnS{sub 2} precursors as a new route for single phase SnS thin films

Energy Technology Data Exchange (ETDEWEB)

Sousa, M.G., E-mail: martasousa@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Cunha, A.F. da, E-mail: antonio.cunha@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Fernandes, P.A., E-mail: pafernandes@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto (Portugal)

2014-04-01

then correlated with the annealing temperature. Scanning electron microscopy studies revealed that the SnS films exhibit small grain structure and the film surface is rough. Optical measurements were performed, from which the band gap energies were estimated. These studies show that the direct absorption transitions of SnS are at 1.68 eV and 1.41 eV for annealing in graphite box with and without elemental sulphur evaporation, respectively. For the indirect transition the values varied from 1.49 eV to 1.37 eV. The results of this work show that the third approach is better suited to produce single phase SnS films. However, a finer tunning of the duration of the high temperature plateau of the annealing profile is required in order to eliminate the β-Sn top layer.

Isomer shifts and chemical bonding in crystalline Sn(II) and Sn(IV) compounds

International Nuclear Information System (INIS)

Terra, J.; Guenzburger, D.

1991-01-01

First-principles self-consistent Local Density calculations of the electronic structure of clusters representing Sn(II) (SnO, SnF 2 , SnS, SnSe) and Sn(IV) (SnO 2 , SnF 4 ) crystalline compounds were performed. Values of the electron density at the Sn nucleus were obtained and related to measured values of the Moessbauer Isomer Shifts reported in the literature. The nuclear parameter of 119 Sn derived was ΔR/R=(1.58±0.14)x10 -4 . The chemical bonding in the solids was analysed and related to the electron densities obtained. (author)

A radio/optical reference frame. 5: Additional source positions in the mid-latitude southern hemisphere

Science.gov (United States)

Russell, J. L.; Reynolds, J. E.; Jauncey, D. L.; de Vegt, C.; Zacharias, N.; Ma, C.; Fey, A. L.; Johnston, K. J.; Hindsley, R.; Hughes, J. A.; Malin, D. F.; White, G. L.; Kawaguchi, N.; Takahashi, Y.

1994-01-01

We report new accurate radio position measurements for 30 sources, preliminary positions for two sources, improved radio postions for nine additional sources which had limited previous observations, and optical positions and optical-radio differences for six of the radio sources. The Very Long Baseline Interferometry (VLBI) observations are part of the continuing effort to establish a global radio reference frame of about 400 compact, flat spectrum sources, which are evenly distributed across the sky. The observations were made using Mark III data format in four separate sessions in 1988-89 with radio telescopes at Tidbinbilla, Australia, Kauai, USA, and Kashima, Japan. We observed a total of 54 sources, including ten calibrators and three which were undetected. The 32 new source positions bring the total number in the radio reference frame catalog to 319 (172 northern and 147 southern) and fill in the zone -25 deg greater than delta greater than -45 deg which, prior to this list, had the lowest source density. The VLBI positions have an average formal precision of less than 1 mas, although unknown radio structure effects of about 1-2 mas may be present. The six new optical postion measurements are part of the program to obtain positions of the optical counterparts of the radio reference frame source and to map accurately the optical on to the radio reference frames. The optical measurements were obtained from United States Naval Observatory (USNO) Black Birch astrograph plates and source plates from the AAT, and Kitt Peak National Observatory (KPNO) 4 m, and the European Southern Observatory (ESO) Schmidt. The optical positions have an average precision of 0.07 sec, mostly due to the zero point error when adjusted to the FK5 optical frame using the IRS catalog. To date we have measured optical positions for 46 sources.

Fully transparent thin-film transistor devices based on SnO2 nanowires.

Science.gov (United States)

Dattoli, Eric N; Wan, Qing; Guo, Wei; Chen, Yanbin; Pan, Xiaoqing; Lu, Wei

2007-08-01

We report on studies of field-effect transistor (FET) and transparent thin-film transistor (TFT) devices based on lightly Ta-doped SnO2 nano-wires. The nanowire-based devices exhibit uniform characteristics with average field-effect mobilities exceeding 100 cm2/V x s. Prototype nano-wire-based TFT (NW-TFT) devices on glass substrates showed excellent optical transparency and transistor performance in terms of transconductance, bias voltage range, and on/off ratio. High on-currents and field-effect mobilities were obtained from the NW-TFT devices even at low nanowire coverage. The SnO2 nanowire-based TFT approach offers a number of desirable properties such as low growth cost, high electron mobility, and optical transparency and low operation voltage, and may lead to large-scale applications of transparent electronics on diverse substrates.

One-Dimensional SnO2 Nano structures: Synthesis and Applications

International Nuclear Information System (INIS)

Pan, J.; Shen, H.; Mathur, S.; Pan, J.

2012-01-01

Nano scale semiconducting materials such as quantum dots (0-dimensional) and one-dimensional (1D) structures, like nano wires, nano belts, and nano tubes, have gained tremendous attention within the past decade. Among the variety of 1D nano structures, tin oxide (SnO 2 ) semiconducting nano structures are particularly interesting because of their promising applications in optoelectronic and electronic devices due to both good conductivity and transparence in the visible region. This article provides a comprehensive review of the recent research activities that focus on the rational synthesis and unique applications of 1D SnO 2 nano structures and their optical and electrical properties. We begin with the rational design and synthesis of 1D SnO 2 nano structures, such as nano tubes, nano wires, nano belts, and some heterogeneous nano structures, and then highlight a range of applications (e.g., gas sensor, lithium-ion batteries, and nano photonics) associated with them. Finally, the review is concluded with some perspectives with respect to future research on 1D SnO 2 nano structures

Optical properties of metals by spectroscopic ellipsometry

International Nuclear Information System (INIS)

Arakawa, E.T.; Inagaki, T.; Williams, M.W.

1979-01-01

The use of spectroscopic ellipsometry for the accurate determination of the optical properties of liquid and solid metals is discussed and illustrated with previously published data for Li and Na. New data on liquid Sn and Hg from 0.6 to 3.7 eV are presented. Liquid Sn is Drude-like. The optical properties of Hg deviate from the Drude expressions, but simultaneous measurements of reflectance and ellipsometric parameters yield consistent results with no evidence for vectorial surface effects

Synthesis, structural, magnetic and optical properties of Sr2CoSn based inverse Heusler alloy nanoparticles

Science.gov (United States)

Asvini, V.; Saravanan, G.; Kalaiezhily, R. K.; Ravichandran, K.

2018-05-01

The peculiar ternary full Heusler alloy Sr2CoSn nanoparticles are synthesized by co-precipitation method. X- ray diffraction pattern confirms the formation of XA or Xα structure of Sr2CoSn. Using Williamson-Hall plot (W-H plot), we are able to use the uniform deformation model and get low value of strain induced broadening. UV-Visible absorption spectrum shows sharp absorption peak at 210 nm and the estimated band gap energy of Sr2CoSn Heusler alloy nanoparticles is Eg = 4.6 eV (from Tauc plot). The presence of Sr2CoSn with the particle size of approximately 90 nm was observed using high resolution scanning electron microscopy. The magnetization measurements were carried out using VSM and studied M verses H hysteresis studies.

Gas Sensing Properties of ZnO-SnO2 Nanostructures.

Science.gov (United States)

Chen, Weigen; Li, Qianzhu; Xu, Lingna; Zeng, Wen

2015-02-01

One-dimensional (1D) semiconductor metal oxide nanostructures have attracted increasing attention in electrochemistry, optics, magnetic, and gas sensing fields for the good properties. N-type low dimensional semiconducting oxides such as SnO2 and ZnO have been known for the detection of inflammable or toxic gases. In this paper, we fabricated the ZnO-SnO2 and SnO2 nanoparticles by hydrothermal synthesis. Microstructure characterization was performed using X-ray diffraction (XRD) and surface morphologies for both the pristine and doped samples were observed using field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Then we made thin film gas sensor to study the gas sensing properties of ZnO-SnO2 and SnO2 gas sensor to H2 and CO. A systematic comparison study reveals an enhanced gas sensing performance for the sensor made of SnO2 and ZnO toward H2 and CO over that of the commonly applied undecorated SnO2 nanoparticles. The improved gas sensing properties are attributed to the size of grains and pronounced electron transfer between the compound nanostructures and the absorbed oxygen species as well as to the heterojunctions of the ZnO nanoparticles to the SnO2 nanoparticles, which provide additional reaction rooms. The results represent an advance of compound nanostructures in further enhancing the functionality of gas sensors, and this facile method could be applicable to many sensing materials, offering a new avenue and direction to detect gases of interest based on composite tin oxide nanoparticles.

Semiconducting ZnSnN{sub 2} thin films for Si/ZnSnN{sub 2} p-n junctions

Energy Technology Data Exchange (ETDEWEB)

Qin, Ruifeng [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China); Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Cao, Hongtao; Liang, Lingyan, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn; Xie, Yufang; Zhuge, Fei; Zhang, Hongliang; Gao, Junhua; Javaid, Kashif [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, and Key Laboratory of Additive Manufacturing Materials of Zhejiang Province, Ningbo 315201 (China); Liu, Caichi; Sun, Weizhong, E-mail: lly@nimte.ac.cn, E-mail: swz@hebut.edu.cn [Hebei Engineering Laboratory of Photoelectronic Functional Crystals, Hebei University of Technology (HEBUT), Tianjin 300401 (China)

2016-04-04

ZnSnN{sub 2} is regarded as a promising photovoltaic absorber candidate due to earth-abundance, non-toxicity, and high absorption coefficient. However, it is still a great challenge to synthesize ZnSnN{sub 2} films with a low electron concentration, in order to promote the applications of ZnSnN{sub 2} as the core active layer in optoelectronic devices. In this work, polycrystalline and high resistance ZnSnN{sub 2} films were fabricated by magnetron sputtering technique, then semiconducting films were achieved after post-annealing, and finally Si/ZnSnN{sub 2} p-n junctions were constructed. The electron concentration and Hall mobility were enhanced from 2.77 × 10{sup 17} to 6.78 × 10{sup 17 }cm{sup −3} and from 0.37 to 2.07 cm{sup 2} V{sup −1} s{sup −1}, corresponding to the annealing temperature from 200 to 350 °C. After annealing at 300 °C, the p-n junction exhibited the optimum rectifying characteristics, with a forward-to-reverse ratio over 10{sup 3}. The achievement of this ZnSnN{sub 2}-based p-n junction makes an opening step forward to realize the practical application of the ZnSnN{sub 2} material. In addition, the nonideal behaviors of the p-n junctions under both positive and negative voltages are discussed, in hope of suggesting some ideas to further improve the rectifying characteristics.

Positional Accuracy in Optical Trap-Assisted Nanolithography

Science.gov (United States)

Arnold, Craig B.; McLeod, Euan

2009-03-01

The ability to directly print patterns on size scales below 100 nm is important for many applications where the production or repair of high resolution and density features are important. Laser-based direct-write methods have the benefit of quickly and easily being able to modify and create structures on existing devices, but feature sizes are conventionally limited by diffraction. In this presentation, we show how to overcome this limit with a new method of probe-based near-field nanopatterning in which we employ a CW laser to optically trap and manipulate dispersed microspheres against a substrate using a 2-d Bessel beam optical trap. A secondary, pulsed nanosecond laser at 355 nm is directed through the bead and used to modify the surface below the microsphere, taking advantage of the near-field enhancement in order to produce materials modification with feature sizes under 100 nm. Here, we analyze the 3-d positioning accuracy of the microsphere through analytic modeling as a function of experimental parameters. The model is verified in all directions for our experimental conditions and is used to predict the conditions required for improved positional accuracy.

Multicolour modelling of SN 2013dx associated with GRB 130702A★

Science.gov (United States)

Volnova, A. A.; Pruzhinskaya, M. V.; Pozanenko, A. S.; Blinnikov, S. I.; Minaev, P. Yu.; Burkhonov, O. A.; Chernenko, A. M.; Ehgamberdiev, Sh. A.; Inasaridze, R.; Jelinek, M.; Khorunzhev, G. A.; Klunko, E. V.; Krugly, Yu. N.; Mazaeva, E. D.; Rumyantsev, V. V.; Volvach, A. E.

2017-05-01

We present optical observations of SN 2013dx, related to the Fermi burst GRB 130702A, which occurred at red shift z = 0.145. It is the second-best sampled gamma-ray burst (GRB)/supernova (SN) after SN 1998bw. The observational light curves contain more than 280 data points in the uBgrRiz filters until 88 d after the burst, and the data were collected from our observational collaboration (Maidanak Observatory, Abastumani Observatory, Crimean Astrophysical Observatory, Mondy Observatory, National Observatory of Turkey and Observatorio del Roque de los Muchachos) and from the literature. We model numerically the multicolour light curves using the one-dimensional radiation hydrodynamical code stella, previously widely implemented for modelling typical non-GRB SNe. The best-fitting model has the following parameters: pre-SN star mass M = 25 M⊙; mass of the compact remnant MCR = 6 M⊙; total energy of the outburst Eoburst = 3.5 × 1052 erg; pre-supernova star radius R = 100 R⊙; M_^{56Ni} = 0.2 M_{⊙}, which is totally mixed through the ejecta; MO = 16.6 M⊙; MSi = 1.2 M⊙ and MFe = 1.2 M⊙, and the radiative efficiency of the SN is 0.1 per cent.

States in 118Sn from 117Sn(d,p) 118Sn at 12 MeV

International Nuclear Information System (INIS)

Frota-Pessoa, E.

1983-01-01

118 Sn energy levels up to = 5.2 MeV excitation energy are studied in the reaction 117 Sn (d,p) 118 Sn. Deuterons had a bombarding energy of 12 MeV. The protons were analized by a magnetic spectrograph. The detector was nuclear emulsion and the resolution in energy about 10 KeV. The distorted-wave analysis was used to determine l values and spectroscopic strengths. Centers of gravity and the sums of reduced spectroscopic factors are presented for the levels when it was possible to determine the S' value. 66 levels of excitation energy were found which did not appear in previous 117 Sn (d,p) reactions. 40 levels were not found previously in any reaction giving 118 Sn. The results are compared with the known ones. (Author) [pt

Defect properties of Sn- and Ge-doped ZnTe: suitability for intermediate-band solar cells

Science.gov (United States)

Flores, Mauricio A.

2018-01-01

We investigate the electronic structure and defect properties of Sn- and Ge- doped ZnTe by first-principles calculations within the DFT+GW formalism. We find that ({{{Sn}}}{{Zn}}) and ({{{Ge}}}{{Zn}}) introduce isolated energy levels deep in the band gap of ZnTe, derived from Sn-5s and Ge-4s states, respectively. Moreover, the incorporation of Sn and Ge on the Zn site is favored in p-type ZnTe, in both Zn-rich and Te-rich environments. The optical absorption spectra obtained by solving the Bethe-Salpeter equation reveals that sub-bandgap absorptance is greatly enhanced due to the formation of the intermediate band. Our results suggest that Sn- and Ge-doped ZnTe would be a suitable material for the development of intermediate-band solar cells, which have the potential to achieve efficiencies beyond the single-junction limit.

Effect of In addition on some physical properties of Sn20Se(60-x) Bi20 amorphous films

International Nuclear Information System (INIS)

Amer, H.H.; Abdel-wahab, A.A.; Abdel-Mongy, A.

2012-01-01

The present paper reports the effect of replacement of selenium by indium on the optical gap and some other physical parameters of new quaternary chalcogenide In x Sn 20 Se (60-x) Bi 20 (x = 0, 0.1, 0.2 and 0.3 at. %) thin films. Thin films with thickness 100 nm of In x Sn 20 Se (60-x) Bi 20 were prepared by thermal evaporation of the bulk samples. Increasing indium content is found to affect the average heat of atomization, the average coordination number, the number of constraints and the cohesive energy of the In x Sn 20 Se (60-x) Bi 20 alloys. Optical absorption measurements showed that the fundamental absorption edge is a function of composition. The optical absorption is due to allowed non-direct transition and the energy gap decreases with the increase of indium content. The chemical bond approach has been applied successfully to interpret the decrease of the optical gap with increasing indium content. The prepared films were irradiated by gamma rays at doses up to 15 Mrad. It was found that the compositions were almost stable against gamma radiation.

Enhanced B doping in CVD-grown GeSn:B using B δ-doping layers

Science.gov (United States)

Kohen, David; Vohra, Anurag; Loo, Roger; Vandervorst, Wilfried; Bhargava, Nupur; Margetis, Joe; Tolle, John

2018-02-01

Highly doped GeSn material is interesting for both electronic and optical applications. GeSn:B is a candidate for source-drain material in future Ge pMOS device because Sn adds compressive strain with respect to pure Ge, and therefore can boost the Ge channel performances. A high B concentration is required to obtain low contact resistivity between the source-drain material and the metal contact. To achieve high performance, it is therefore highly desirable to maximize both the Sn content and the B concentration. However, it has been shown than CVD-grown GeSn:B shows a trade-off between the Sn incorporation and the B concentration (increasing B doping reduces Sn incorporation). Furthermore, the highest B concentration of CVD-grown GeSn:B process reported in the literature has been limited to below 1 × 1020 cm-3. Here, we demonstrate a CVD process where B δ-doping layers are inserted in the GeSn layer. We studied the influence of the thickness between each δ-doping layers and the δ-doping layers process conditions on the crystalline quality and the doping density of the GeSn:B layers. For the same Sn content, the δ-doping process results in a 4-times higher B doping than the co-flow process. In addition, a B doping concentration of 2 × 1021 cm-3 with an active concentration of 5 × 1020 cm-3 is achieved.

Synthesis of Monodisperse Walnut-Like SnO2 Spheres and Their Photocatalytic Performances

Directory of Open Access Journals (Sweden)

Jing Wang

2015-01-01

Full Text Available Novel walnut-like SnO2 spheres have been synthesized using a one-step hydrothermal reaction with SnCl2·2H2O and KOH as raw materials. The morphology, microstructure, and optical properties of the products were characterized by X-ray powder diffraction (XRD, Raman spectrum, scanning electron microscopy (SEM, transmission electron microscopy (TEM, selected area electron diffraction (SAED, and ultraviolet-visible (UV-Vis absorption spectroscopy. The detailed studies revealed that these synthesized spheres are highly monodisperse and have a uniform size of approximately 250 nm. Photocatalytic activity of the prepared SnO2 spheres was evaluated by the degradation of methylene orange. The synthesized SnO2 spheres exhibited excellent photocatalytic degradation. In addition, a possible formation mechanism of the walnut-like nanostructures was proposed based on reaction time-dependent experiments.

Reactive pulsed laser deposition of Cu2ZnSnS4 thin films in H2S

International Nuclear Information System (INIS)

Surgina, G.D.; Zenkevich, A.V.; Sipaylo, I.P.; Nevolin, V.N.; Drube, W.; Teterin, P.E.; Minnekaev, M.N.

2013-01-01

Cu 2 ZnSnS 4 (CZTS) thin films have been grown by reactive pulsed laser deposition in H 2 S atmosphere, combining the alternate ablation from the metallic (Cu) and alloyed (Zn x Sn) targets at room temperature. The morphological, structural and optical properties of as grown CZTS thin films with varying compositions as well as upon annealing in N 2 atmosphere are investigated by Rutherford backscattering spectrometry, X-ray diffraction, Raman spectroscopy and optical spectrophotometry. The chemical bonding in the “bulk” of the CZTS films is elucidated via hard X-ray photoemission spectroscopy measurements. The formation of the good quality stoichiometric polycrystalline CZTS films is demonstrated upon optimization of the growth parameters. - Highlights: ► The new method of Cu 2 ZnSnS 4 (CZTS) thin films growth in H 2 S was realized. ► CZTS films were grown by pulsed laser deposition from Cu and alloyed Zn–Sn targets. ► The effect of the processing parameters on the CZTS properties was investigated. ► The chemical bonding in the “bulk” of CZTS films was studied

Effects of interlayer Sn-Sn lone pair interaction on the band gap of bulk and nanosheet SnO

Science.gov (United States)

Umezawa, Naoto; Zhou, Wei

2015-03-01

Effects of interlayer lone-pair interactions on the electronic structure of SnO are firstly explored by the density-functional theory. Our comprehensive study reveals that the band gap of SnO opens as increase in the interlayer Sn-Sn distance. The effect is rationalized by the character of band edges which consists of bonding and anti-bonding states from interlayer lone pair interactions. The band edges for several nanosheets and strained double-layer SnO are estimated. We conclude that the double-layer SnO is a promising material for visible-light driven photocatalyst for hydrogen evolution. This work is supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) program.

Stripped-envelope supernova SN 2004dk is now interacting with hydrogen-rich circumstellar material

Science.gov (United States)

Mauerhan, Jon C.; Filippenko, Alexei V.; Zheng, WeiKang; Brink, Thomas; Graham, Melissa L.; Shivvers, Isaac; Clubb, Kelsey

2018-05-01

The dominant mechanism and time scales over which stripped-envelope supernovae (SNe) progenitor stars shed their hydrogen envelopes are uncertain. Observations of Type Ib and Ic SNe at late phases could reveal the optical signatures of interaction with distant circumstellar material (CSM) providing important clues on the origin of the necessary pre-SN mass loss. We report deep late-time optical spectroscopy of the Type Ib explosion SN 2004dk 4684 days (13 years) after discovery. We detect strong Hα emission with an intermediate line width of ˜400 km s-1 and luminosity ˜2.5 × 1039 erg s-1, signaling that the SN blast wave has caught up with the hydrogen-rich CSM lost by the progenitor system. The line luminosity is the highest ever reported for a SN at this late stage. Prominent emission features of He I, Fe, and Ca are also detected. The spectral characteristics are consistent with CSM energized by the forward shock, and resemble the late-time spectra of the persistently interacting Type IIn SNe 2005ip and 1988Z. We suggest that the onset of interaction with H-rich CSM was associated with a previously reported radio rebrightening at ˜1700 days. The data indicate that the mode of pre-SN mass loss was a relatively slow dense wind that persisted millennia before the SN, followed by a short-lived Wolf-Rayet phase that preceded core-collapse and created a cavity within an extended distribution of CSM. We also present new spectra of SNe 2014C, PTF11iqb, and 2009ip, all of which also exhibit continued interaction with extended CSM distributions.

Laser created thin films sensors based on Sn- and indium compounds

Czech Academy of Sciences Publication Activity Database

Myslík, V.; Vysloužil, F.; Vrňata, M.; Fryček, R.; Jelínek, Miroslav; Lančok, Ján

2002-01-01

Roč. 12, č. 2 (2002), s. 329-333 ISSN 1054-660X Institutional research plan: CEZ:AV0Z1010921 Keywords : PLD * Sn-based thin films * In-based thin films Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.798, year: 2002

VERY LATE PHOTOMETRY OF SN 2011fe

International Nuclear Information System (INIS)

Kerzendorf, W. E.; Taubenberger, S.; Seitenzahl, I. R.; Ruiter, A. J.

2014-01-01

The Type Ia supernova SN 2011fe is one of the closest supernovae of the past decades. Due to its proximity and low dust extinction, this object provides a very rare opportunity to study the extremely late time evolution (>900 days) of thermonuclear supernovae. In this Letter, we present our photometric data of SN 2011fe taken at an unprecedented late epoch of ≈930 days with GMOS-N mounted on the Gemini North telescope (g = 23.43 ± 0.28, r = 24.14 ± 0.14, i = 23.91 ± 0.18, and z = 23.90 ± 0.17) to study the energy production and retention in the ejecta of SN 2011fe. Together with previous measurements by other groups, our result suggests that the optical supernova light curve can still be explained by the full thermalization of the decay positrons of 56 Co. This is in spite of theoretical predicted effects (e.g., infrared catastrophe, positron escape, and dust) that advocate a substantial energy redistribution and/or loss via various processes that result in a more rapid dimming at these very late epochs

Oxidation of Pb-Sn and Pb-Sn-In alloys

International Nuclear Information System (INIS)

Sluzewski, D.A.; Chang, Y.A.; Marcotte, V.C.

1990-01-01

Air oxidized Pb-Sn and Pb-Sn-In single phase alloys have been studied with scanning Auger microscopy. Line scans across grain boundaries combined with argon ion sputter etching revealed grain boundary oxidation. In the Pb-Sn samples, tin is preferentially oxidized with the grain boundary regions having a much higher percentage of tin oxide than the bulk surface oxide. In the Pb-Sn-In alloys, both tin and indium are preferentially oxidized with the grain boundary regions being enriched with tin and indium oxides

Phase controlled solvothermal synthesis of Cu{sub 2}ZnSnS{sub 4}, Cu{sub 2}ZnSn(S,Se){sub 4} and Cu{sub 2}ZnSnSe{sub 4} Nanocrystals: The effect of Se and S sources on phase purity

Energy Technology Data Exchange (ETDEWEB)

Pal, Mou [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico); Instituto de Física, BUAP, Av. San Claudio y Blvd. 18 Sur Col. San Manuel, Ciudad Universitaria, C.P. 72570, Puebla (Mexico); Mathews, N.R. [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico); Paraguay-Delgado, F. [Departamento de Materiales Nanoestructurados, Centro de Investigación en Materiales Avanzados (CIMAV), Chihuahua (Mexico); Mathew, X., E-mail: xm@ier.unam.mx [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580 Temixco, Morelos (Mexico)

2015-09-15

In this study, we have reported the synthesis of Cu{sub 2}ZnSnSe{sub 4} (CZTSe), Cu{sub 2}ZnSnS{sub 4} (CZTS) and Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) nanocrystals with tunable band gap and composition obtained by solvothermal method. The crystalline structure, composition, morphology and optical properties of the nanoparticles were characterized by X-ray diffraction (XRD), Raman scattering, energy dispersive X-ray spectroscopy, transmission electron microscopy and diffuse reflectance (DR) spectroscopy. While the XRD patterns of CZTS and CZTSe nanoparticles prepared with elemental S/Se powder revealed the presence of phase pure nanoparticles, the CZTSSe nanoparticles obtained using a mixture of S and Se, were found to contain many secondary phases under the same synthesis protocol. Formation of impurity phases in CZTSSe sample, can be avoided by using a mixture of 1-dodecanethiol (DT; CH{sub 3}(CH{sub 2}){sub 11}SH)/oleylamine (OLA) instead of S powder and following the same experimental procedure. The incorporation of S in CZTSe nanocrystals prepared in presence of DDT/OLA mixture was confirmed through structural and optical characterizations. The optical properties of the quaternary chalcogenide nanocrystals were found to vary with the chemical composition of the material. - Highlights: • Solvothermal synthesis of CZTS, CZTSSe and CZTSe nanocrystals and discussion on possible formation mechanism. • Use of dodecanethiol/oleylamine mixture to synthesize phase-pure CZTSSe nanocrystals. • Formation of impurity phases can be controlled with proper S and Se sources.

Structural, optical and photoluminescence study of nanocrystalline

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 37; Issue 3. Structural, optical ... Orientation along plane (200) decreases continuously as molar concentration of SnO2 increases. Dislocation density along plane (110) also decreases as molar concentration increases except 0.4 M SnO2 thin film. Scanning electron ...

Polarimetry of SN 2014J in M82 as a Probe of Its Dusty Environment

Science.gov (United States)

Wang, Lifan

2014-10-01

Late time polarimetry can effectively probe the circumstellar (CS) dust environment of SNe Ia. We propose to acquire imaging polarimetry of SN 2014J at three epochs between 200-400 days after the SN explosion. The delayed light from optical maximum may be scattered into the line of sight and reveal the scattering dust through polarization. Light echoes from interstellar dust at very large distances (> 10pc) from the SN will not be highly polarized in these observations due to the small scattering angle involved. Polarimetry at late time is thus an unambegeous probe of CS dust very close to the SN (at distances ~ 1 light year). Observations of the illusive CS matter is critical in constraining the progenitor systems of SNIa.

SN 2006bt: A PERPLEXING, TROUBLESOME, AND POSSIBLY MISLEADING TYPE Ia SUPERNOVA

International Nuclear Information System (INIS)

Foley, Ryan J.; Narayan, Gautham; Challis, Peter J.; Kirshner, Robert P.; Filippenko, Alexei V.; Silverman, Jeffrey M.; Steele, Thea N.

2010-01-01

SN 2006bt displays characteristics unlike those of any other known Type Ia supernova (SN Ia). We present optical light curves and spectra of SN 2006bt which demonstrate the peculiar nature of this object. SN 2006bt has broad, slowly declining light curves indicative of a hot, high-luminosity SN, but lacks a prominent second maximum in the i band as do low-luminosity SNe Ia. Its spectra are similar to those of low-luminosity SNe Ia, containing features that are only present in cool SN photospheres. Light-curve fitting methods suggest that SN 2006bt is reddened by a significant amount of dust; however, it occurred in the outskirts of its early-type host galaxy and has no strong Na D absorption in any of its spectra, suggesting a negligible amount of host-galaxy dust absorption. C II is possibly detected in our pre-maximum spectra, but at a much lower velocity than other elements. The progenitor was likely very old, being a member of the halo population of a galaxy that shows no signs of recent star formation. SNe Ia have been very successfully modeled as a one-parameter family, and this is fundamental to their use as cosmological distance indicators. SN 2006bt is a challenge to that picture, yet its relatively normal light curves allowed SN 2006bt to be included in cosmological analyses. We generate mock SN Ia data sets which indicate that contamination by similar objects will both increase the scatter of a SN Ia Hubble diagram and systematically bias measurements of cosmological parameters. However, spectra and rest-frame i-band light curves should provide a definitive way to identify and eliminate such objects.

Analyses of the Sn IX-Sn XII spectra in the EUV region

International Nuclear Information System (INIS)

Churilov, S S; Ryabtsev, A N

2006-01-01

The Sn IX-Sn XII spectra excited in a vacuum spark have been analysed in the 130-160 A wavelength region. The analysis was based on the energy parameter extrapolation in the isonuclear Sn VI-VIII and Sn XIII-XIV sequence. 266 spectral lines belonging to the 4d m -(4d m-1 4f+4p 5 4d m+1 ) (m=6-3) transition arrays were classified in the Sn IX-Sn XII spectra for the first time. All 18 level energies of the 4d 3 configuration and 39 level energies of the strongly interacting 4d 2 4f and 4p 5 4d 4 configurations were established in the Sn XII spectrum. The energy differences between the majority of the 4d m levels and about 40 levels of the 4d m-1 4f+4p 5 4d m+1 configurations were determined in each of the Sn IX, Sn X and Sn XI spectra (m=6-4). As a result, all intense lines were classified in the 130-140 A region relevant to the extreme ultraviolet (EUV) lithography. It was shown that the most of the intense lines in the 2% bandwidth at 135 A belong to the transitions in the Sn XI-Sn XIII spectra

Effect of SbSn additions on the physical characterization of amorphous Se

Energy Technology Data Exchange (ETDEWEB)

Abdel-Rahim, Farid M., E-mail: farid.elkhateb@gmail.com [Physics Department, Faculty of Science, Al-Azhar, University, Assiut Branch, Assiut (Egypt); Physics Department, Faculty of Science and Arts, Khulais, King Abdulaziz University (KAU) (Saudi Arabia); Aly, K.A., E-mail: Kamalaly2001@gmail.com [Physics Department, Faculty of Science, Al-Azhar, University, Assiut Branch, Assiut (Egypt); Physics Department, Faculty of Science and Arts, Khulais, King Abdulaziz University (KAU) (Saudi Arabia); Dahshan, A. [Department of Physics, Faculty of Science, Port Said, University, Port Said (Egypt); Physics Department - Faculty of Girls - King Khalid University, Abha (Saudi Arabia)

2011-08-15

Highlights: {yields} The present work deals with the incorporation the optical properties of amorphous Se with SbSn. {yields} High accuracy determination of the film thickness and the complex index of refraction. {yields} The allowed non-direct electronic transitions are mainly responsible for the photon absorption in the investigated films. {yields} The changes in the refractive index were discussed in terms of the single-oscillator model (Wemple-DiDomenico relationship). {yields} The obtained results were discussed in terms of the chemical-bond approach. - Abstract: Different compositions of Se{sub 100-x}(SbSn){sub x} (0 {<=} x {<=} 14 at.%) glasses were prepared by the well-known melt quench technique. Thin films of these glasses were prepared by thermal evaporation onto ultrasonic cleaned glass substrate. Transmittance spectra of these films were measured in the wavelength range 400-2500 nm by using Jasco double beam spectrophotometer. A straight forward analysis proposed by Swanepoel, based on the maxima and minima of the transmittance spectra, allows to accurate determination of the film thickness and the complex index of refraction. Increasing SbSn content at the expense of Se atoms is found to affect the refractive index and the extinction coefficient of these films. The refractive indexes were discussed in terms of the single-oscillator Wemple-DiDomenico model. The compositional dependence of the optical band gap for the Se{sub 100-x}(SbSn){sub x} (0 {<=} x {<=} 14 at.%) thin films is discussed in terms of the chemical-bond approach.

Rod-like hierarchical Sn/SnOx@C nanostructures with enhanced lithium storage properties

Science.gov (United States)

Yang, Juan; Chen, Sanmei; Tang, Jingjing; Tian, Hangyu; Bai, Tao; Zhou, Xiangyang

2018-03-01

Rod-like hierarchical Sn/SnOx@C nanostructures have been designed and synthesized via calcining resorcinol-formaldehyde (RF) resin coated Sn-based metal-organic frameworks. The rod-like hierarchical Sn/SnOx@C nanostructures are made of a great number of carbon-wrapped primary Sn/SnOx nanospheres of 100-200 nm in diameter. The as-prepared hierarchical Sn/SnOx@C nanocomposite manifests a high initial reversible capacity of 1177 mAh g-1 and remains 1001 mAh g-1 after 240 cycles at a current density of 200 mA g-1. It delivers outstanding high-rate performance with a reversible capacity of 823 mAh g-1 even at a high current density of 1000 mA g-1. The enhanced electrochemical performances of the Sn/SnOx@C electrode are mainly attributed to the synergistic effect of the unique hierarchical micro/nanostructures and the protective carbon layer.

Influence of Sn incorporation on the properties of CuInS2 thin films grown by vacuum evaporation method

International Nuclear Information System (INIS)

Zribi, M.; Rabeh, M. Ben; Brini, R.; Kanzari, M.; Rezig, B.

2006-01-01

Structural, morphological and optical properties of Sn-doped CuInS 2 thin films grown by double source thermal evaporation method were studied. Firstly, the films were annealed in vacuum after evaporation from 250 to 500 deg. C for Sn deposition time equal to 3 min. Secondly, the films deposited for several Sn evaporation times were annealed in vacuum after evaporation at 500 deg. C. The X-ray diffraction spectra indicated that polycrystalline Sn-doped CuInS 2 films were obtained and no Sn binary or ternary phases are observed for the Sn evaporation times equal to 5 min. Scanning electron microscopy observation revealed the decrease of the surface crystallinity with increasing the Sn evaporation times and the annealing temperatures. The Sn-doped samples after annealing have bandgap energy of 1.42-1.50 eV. Furthermore, we found that the Sn-doped CuInS 2 thin films exhibit N-type conductivity after annealing

First-principles studies on the properties of Cu2ZnSnS4 grain-b oundaries due to photovoltaic effect%Cu2ZnSnS4晶界性质与光伏效应的第一性原理研究∗

Institute of Scientific and Technical Information of China (English)

范巍; 曾雉

2015-01-01

lattice defects so that Sn2+ ions have the lower coordination number by bonding 3 S atoms. The Sn atom is favored to be at the center of S octahedron with six neighboring S (or O) atoms in most sulfides (oxides) of tin. In CZTS, Sn atom is at the center of tetrahedron with 4 neighboring S atoms so that Sn atom is very active to move by structural relaxations. Most importantly the conduction-bands in CZTS are formed by the hybridizations between the s electrons of Sn and p electrons of S so that the conduction-bands of CZTS are sensitively dependent on the distributions and properties of Sn atoms. The appearing of Sn2+ ions and the strong structural relaxations of Sn atoms in grain-boundary regions and on surfaces induce extra in-gap states as a new source for the recombination of electron-hole pairs that are un-favored to the photo-voltage effects. Generally, the grain boundary plays a negative role in brittle photo-voltage materials such as Si and GaAs, and the positive role in ductile photo-voltage materials such as CdTe and CIGS (Cu(InGa)Se2). It means that the growth of the hard and brittle films is very difficult, the micro-cracks and micro-pores are easily created. Our calculations show that CdTe, CIGS and CZTS are all ductile with Poisson-ratio greater than 0.33. This means that CZTS can be used as the absorber of flexible solar cell. By comparing the optical absorption-coefficients of crystals, grain-boundaries, surfaces and nano-particles, we find that the internal surfaces in thin-films with high pore-ratio can create new energy-levels in band-gap, which enhances the recombination between electrons and holes and decreases the optical absorption-coefficients (>1.3 eV). As a result, the high dense CZTS thin-film is required for high-efficient CZTS solar-cell. The positive role of grain boundary is more important if the CZTS film has the large, unique oriented grains and the uniform distribution of grain sizes. The simple and regular grain-boundary network is more

Evidence for highly localized damage in internal tin and powder-in-tube Nb{sub 3}Sn strands rolled before reaction obtained from coupled magneto-optical imaging and confocal laser scanning microscopy

Energy Technology Data Exchange (ETDEWEB)

Polyanskii, A A; Lee, P J; Jewell, M C; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Barzi, E; Turrioni, D; Zlobin, A V [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2009-09-15

Nb{sub 3}Sn strands for high-current, high-field magnets must be cabled before reaction while the conductor is still composed of ductile components. Even though still in the ductile, deformable state, significant damage can occur in this step, which expresses itself by inhomogeneous A15 formation, Sn leakage or even worse effects during later reaction. In this study, we simulate cabling damage by rolling recent high performance powder-in-tube (PIT) and internal tin (IT) strands in controlled increments, applying standard Nb{sub 3}Sn reaction heat treatments, and then examining the local changes using magneto-optical imaging (MOI), scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). These combined characterizations allow any local damage to the filament architecture to be made clear. MOI directly reveals the local variation of superconductivity while CLSM is extremely sensitive in revealing Sn leakage beyond the diffusion barrier into the stabilizing Cu. These techniques reveal a markedly different response to deformation by the PIT and IT strands. The study demonstrates that these tools can provide a local, thorough, and detailed view of how strands degrade and thus complement more complex extracted strand studies.

The Cu2ZnSnSe4 thin films solar cells synthesized by electrodeposition route

Science.gov (United States)

Li, Ji; Ma, Tuteng; Wei, Ming; Liu, Weifeng; Jiang, Guoshun; Zhu, Changfei

2012-06-01

An electrodeposition route for preparing Cu2ZnSnSe4 thin films for thin film solar cell absorber layers is demonstrated. The Cu2ZnSnSe4 thin films are prepared by co-electrodeposition Cu-Zn-Sn metallic precursor and subsequently annealing in element selenium atmosphere. The structure, composition and optical properties of the films were investigated by X-ray diffraction (XRD), Raman spectrometry, energy dispersive spectrometry (EDS) and UV-VIS absorption spectroscopy. The Cu2ZnSnSe4 thin film with high crystalline quality was obtained, the band gap and absorption coefficient were 1.0 eV and 10-4 cm-1, which is quite suitable for solar cells fabrication. A solar cell with the structure of ZnO:Al/i-ZnO/CdS/Cu2ZnSnSe4/Mo/glass was fabricated and achieved an conversion efficiency of 1.7%.

Spray pyrolysis deposition of Cu-ZnO and Zn-SnO{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Khelfane, A.; Tarzalt, H.; Sebboua, B.; Zerrouki, H.; Kesri, N., E-mail: kesri5n@gmail.com [Faculty of Physics, University of Science and Technology of Houari Boumediene, Algiers (Algeria)

2015-12-31

Large-gap metal oxides, such as titanium, tin, and zinc oxides, have attracted great interest because of their remarkable potential in dye-sensitized solar cells (DSSC) and their low cost and simple preparation procedure. In this work, we investigated several Zn-SnO{sub 2} and Cu-ZnO thin films that were sprayed under different experimental conditions. We varied [Zn/[Sn] and [Cu/[Zn] ratios, calculated on atomic percent in the starting solution. We report some structural results of the films using X-ray diffraction. Optical reflection and transmission spectra investigated by an UV/VIS/NIR spectrophotometer permit the determination of optical constants. The direct band gap was deduced from the photon energy dependence of the absorption coefficient.

Interfacial microstructures and solder joint strengths of the Sn-8Zn-3Bi and Sn-9Zn-lAl Pb-free solder pastes on OSP finished printed circuit boards

Energy Technology Data Exchange (ETDEWEB)

Lin, C.-T. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China); Hsi, C.-S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Wang, M.-C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: mcwang@kmu.edu.tw; Chang, T.-C.; Liang, M.-K. [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China)

2008-07-14

Two kinds of lead-free solders, Sn-8Zn-3Bi and Sn-9Zn-lAl, were used to mount passive components onto printed circuit boards via a re-flow soldering process. The samples were stored at 150 deg. C for 200, 400, 600, 800, and 1100 h. The microstructures of the samples after aged at 150 deg. C for various times were characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and the analyzed of solder joint shear strengths. The joint strength between Sn-8Zn-3Bi and Cu pad was about 4.0 {+-} 0.3 kg, while the strength between Sn-9Zn-lAl and Cu pad had values of 2.6 {+-} 0.1 kg. Both kinds of solder joints exhibited reduced strengths with increasing aging times. After aging at 150 deg. C for 1100 h, the joints strengths of Sn-8Zn-3Bi and Sn-9Zn-lAl were 1.8 {+-} 0.3 and 1.7 {+-} 0.3 kg, respectively. Both the Sn-8Zn-3Bi and Sn-9Zn-lAl joints showed brittle fracture behaviors. A flat layer of Cu{sub 5}Zn{sub 8} intermetallic compound (IMC) was formed between Sn-8Zn-3Bi solder and Cu pad after reflow. When the aging time was increased to 400 h, Zn-depletion and formation of Cu{sub 6}Sn{sub 5} IMC were observed in the solders due to the interaction between the tin and zinc compounds. The interaction between Sn-9Zn-lAl solder and Cu pad had similar behavior, however, Cu{sub 6}Sn{sub 5} IMC formed in Sn-9Zn-lAl solder when after aging at 150 deg. C for 600 h. As the aging time increased, both types of solders generated clear IMC spalling layers with large and continuous voids. Those voids substantially decreased the joint strength.

Hybrid van der Waals SnO/MoS2 Heterojunctions for Thermal and Optical Sensing Applications

KAUST Repository

Wang, Zhenwei; He, Xin; Zhang, Xixiang; Alshareef, Husam N.

2017-01-01

/oxide hybrid vdWH based on n-type molybdenum disulfide (MoS2) and p-type tin monoxide (SnO) is presented, with promising rectification, thermal-sensing, and photosensing performance. Specifically, the hybrid SnO/MoS2 vdWH shows static rectification ratio of 2

Phase diagram of the Fe-Sn-Zr system at 800 °C

International Nuclear Information System (INIS)

Nieva, N.; Corvalán, C.; Jiménez, M.J.; Gómez, A.; Arreguez, C.; Joubert, J.-M.; Arias, D.

2017-01-01

New experimental results on the Fe-Sn-Zr phase diagram at 800 °C are presented, particularly in the central, Fe rich and Sn rich regions of the Gibbs triangle. Seven ternary alloys were designed, produced and examined by different techniques: optical and scanning electron microscopy, semi-quantitative microanalysis, quantitative microanalysis and X-ray diffraction. The results of this work and previous experimental data were used to determine the phase diagram section at 800 °C which contains at least five ternary compounds: Fe 6 Sn 6 Zr, Y, X′, θ and C36. - Highlights: •A phase diagram of Fe-Sn-Zr system at 800 °C is proposed. •The isothermal section of Fe-Sn-Zr system at 800 °C and that at 900 °C determined previously allow reliable extrapolations at low temperatures. •The study at different temperatures (900 °C and 800 °C in this case) is highly desirable because it allows the separation between enthalpic and entropic effects in a future Calphad modelling.

Phase diagram of the Fe-Sn-Zr system at 800 °C

Energy Technology Data Exchange (ETDEWEB)

Nieva, N. [Laboratorio de Física del Sólido, Departamento de Física, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán (Argentina); Corvalán, C., E-mail: corvalan@cnea.gov.ar [Gerencia de Materiales, Comisión Nacional de Energía Atómica Argentina (CNEA), Universidad Nacional de Tres de Febrero, Argentina, CONICET, Consejo Nacional de Ciencia y Técnica (Argentina); Jiménez, M.J. [IFISUR, CONICET, Departamento de Física, Universidad Nacional del Sur, Bahía Blanca (Argentina); Gómez, A. [Grupo LMFAE – PPFAE, Centro Atómico Ezeiza, Comisión Nacional de Energía Atómica (Argentina); Arreguez, C. [Laboratorio de Física del Sólido, Departamento de Física, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán (Argentina); Joubert, J.-M. [Chimie Métallurgique des Terres Rares (CMTR), Institut de Chimie et des Matériaux Paris-Est (ICMPE), CNRS, Université Paris-Est Créteil, 2-8 rue Henri Dunant, 94320 Thiais Cedex (France); Arias, D. [Instituto de Tecnología J. Sabato, Universidad Nacional de San Martín-CNEA (Argentina)

2017-04-15

New experimental results on the Fe-Sn-Zr phase diagram at 800 °C are presented, particularly in the central, Fe rich and Sn rich regions of the Gibbs triangle. Seven ternary alloys were designed, produced and examined by different techniques: optical and scanning electron microscopy, semi-quantitative microanalysis, quantitative microanalysis and X-ray diffraction. The results of this work and previous experimental data were used to determine the phase diagram section at 800 °C which contains at least five ternary compounds: Fe{sub 6}Sn{sub 6}Zr, Y, X′, θ and C36. - Highlights: •A phase diagram of Fe-Sn-Zr system at 800 °C is proposed. •The isothermal section of Fe-Sn-Zr system at 800 °C and that at 900 °C determined previously allow reliable extrapolations at low temperatures. •The study at different temperatures (900 °C and 800 °C in this case) is highly desirable because it allows the separation between enthalpic and entropic effects in a future Calphad modelling.

Multielemental Determination of As, Bi, Ge, Sb, and Sn in Agricultural Samples Using Hydride Generation Coupled to Microwave-Induced Plasma Optical Emission Spectrometry.

Science.gov (United States)

Machado, Raquel C; Amaral, Clarice D B; Nóbrega, Joaquim A; Araujo Nogueira, Ana Rita

2017-06-14

A microwave-induced plasma optical emission spectrometer with N 2 -based plasma was combined with a multimode sample introduction system (MSIS) for hydride generation (HG) and multielemental determination of As, Bi, Ge, Sb, and Sn in samples of forage, bovine liver, powdered milk, agricultural gypsum, rice, and mineral fertilizer, using a single condition of prereduction and reduction. The accuracy of the developed analytical method was evaluated using certified reference materials of water and mineral fertilizer, and recoveries ranged from 95 to 106%. Addition and recovery experiments were carried out, and the recoveries varied from 85 to 117% for all samples evaluated. The limits of detection for As, Bi, Ge, Sb, and Sn were 0.46, 0.09, 0.19, 0.46, and 5.2 μg/L, respectively, for liquid samples, and 0.18, 0.04, 0.08, 0.19, and 2.1 mg/kg, respectively, for solid samples. The method proposed offers a simple, fast, multielemental, and robust alternative for successful determination of all five analytes in agricultural samples with low operational cost without compromising analytical performance.

Characterization of hydrothermally synthesized SnS nanoparticles for solar cell application

Science.gov (United States)

Rajwar, Birendra Kumar; Sharma, Shailendra Kumar

2018-05-01

In the present study, SnS nanoparticles were synthesized by simple hydrothermal method using stannous chloride and thiourea as tin (Sn) and sulfur (S) precursor respectively. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy and UV-Vis Spectroscopy techniques. XRD pattern reveals that as-prepared nanoparticles exhibit orthorhombic structure. Average particles size was calculated using Scherrer's formula and found to be 23 nm. FESEM image shows that the as-prepared nanoparticles are in plate like structure. Direct optical band gap (Eg) of as-synthesized nanoparticles was calculated through UV-Vis Spectroscopy measurement and found to be 1.34 eV, which is near to optimum need for photovoltaic solar energy conversion (1.5 eV). Thus this SnS, narrowband gap semiconductor material can be applied as an alternative absorber material for solar cell application.

EARLY ULTRAVIOLET/OPTICAL EMISSION OF THE TYPE Ib SN 2008D

Energy Technology Data Exchange (ETDEWEB)

Bersten, Melina C.; Nomoto, Ken' ichi [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Tanaka, Masaomi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501 (Japan); Benvenuto, Omar G., E-mail: melina.bersten@ipmu.jp [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900FWA La Plata (Argentina)

2013-04-20

We propose an alternative explanation for the post-breakout emission of SN 2008D associated with the X-ray transient 080109. Observations of this object show a very small contrast of 0.35 dex between the light-curve minimum occurring soon after the breakout, and the main luminosity peak which is due to radioactive heating of the ejecta. Hydrodynamical models show that the cooling of a shocked Wolf-Rayet star leads to a much greater difference ({approx}> 0.9 dex). Our proposed scenario is that of a jet produced during the explosion which deposits {sup 56}Ni-rich material in the outer layers of the ejecta. The presence of high-velocity radioactive material allows us to reproduce the complete luminosity evolution of the object. Without outer {sup 56}Ni it could be possible to reproduce the early emission purely from cooling of the shocked envelope by assuming a larger progenitor than a Wolf-Rayet star, but that would require an initial density structure significantly different from what is predicted by stellar evolution models. Analytic models of the cooling phase have been proposed reproduce the early emission of SN 2008D with an extended progenitor. However, we found that the models are valid only until 1.5 days after the explosion where only two data of SN 2008D are available. We also discuss the possibility of the interaction of the ejecta with a binary companion, based on published analytic expressions. However, the binary separation required to fit the early emission should be {approx}< 3 R{sub Sun }, which is too small for a system containing two massive stars.

Microstructure and Mechanical Properties of Stainless Steel/Brass Joints Brazed by Sn-Electroplated Ag Brazing Filler Metals

Science.gov (United States)

Wang, Xingxing; Peng, Jin; Cui, Datian

2018-05-01

To develop a high-Sn-content AgCuZnSn brazing filler metal, the BAg50CuZn was used as the base filler metal and a Sn layer was electroplated upon it. Then, the 304 stainless steel and the H62 brass were induction-brazed with the Sn-plated brazing filler metals. The microstructures of the joints were examined with an optical microscope, a scanning electron microscope and an x-ray diffractometer. The corresponding mechanical properties were obtained with a universal tensile testing machine. The results indicated that the induction brazed joints consisted of the Ag phase, the Cu phase and the CuZn phase. When the content of Sn in the Sn-plated Ag brazing filler metal was 6.0 or 7.2 wt.%, the Cu5Zn8, the Cu41Sn11 and the Ag3Sn phases appeared in the brazed joint. The tensile strength of the joints brazed with the Sn-plated filler metal was higher compared to the joints with the base filler metal. When the content of Sn was 6.0 wt.%, the highest tensile strength of the joint reached to 395 MPa. The joint fractures presented a brittle mode, mixed with a low amount of ductile fracture, when the content of Sn exceeded 6.0 wt.%.

In situ Sn2+-incorporation synthesis of titanate nanotubes for photocatalytic dye degradation under visible light illumination

International Nuclear Information System (INIS)

Tsai, Chien-Cheng; Chen, Liang-Che; Yeh, Te-Fu; Teng, Hsisheng

2013-01-01

Highlights: ► Sn 2+ ions sensitize titanate nanotubes for photocatalysis under visible-light illumination. ► The Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanates. ► The presence of Sn 2+ lifts the valence band of titanate nanotubes by approximately 0.9 eV. ► The doped Sn 2+ sites are active in donating photo-induced charges to dye degradation. - Abstract: Sn 2+ -incorporated titanate nanotubes, prepared by washing a layered sodium titanate with a SnCl 2 solution for tube formation, exhibit noticeable photocatalytic activity under visible light irradiation. This in situ synthesis results in a Sn/Ti ratio of approximately 0.6. Because of the introduction of Sn 2+ ions, the Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanate nanotubes. Optical absorption analysis shows that Sn doping reduces the bandgap of titanate nanotubes from 3.5 to 2.6 eV. Oxidation of the Sn 2+ -incorporated titanate nanotubes leads to oxidation of Sn 2+ to Sn 4+ , hence, widening the bandgap. Under visible light irradiation, Sn 2+ -incorporated titanate nanotubes effectively degrade methylene blue in an aqueous solution, whereas the bare titanate nanotubes exhibit substantially lower photocatalytic activity. Photoluminescence analysis demonstrates that the induced charges from excitation of the Sn 2+ ions tend to be relaxed through chemical interactions, rather than irradiative recombination.

Sensors of the gas CO in thin film of SnO{sub 2}:Cu; Sensores del gas CO en pelicula delgada de SnO{sub 2}:Cu

Energy Technology Data Exchange (ETDEWEB)

Tirado G, S.; Sanchez Z, F. E., E-mail: tirado@esfm.ipn.mx [IPN, Escuela Superior de Fisica y Matematicas, Unidad Profesional Adolfo Lopez Mateos, San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)

2011-10-15

Thin films of SnO{sub 2}:Cu with different thickness, were deposited on soda-lime glass substrates and prepared by the Sol-gel process and repeated immersion. The sensor properties of these films to the gas CO for the range of 0-200 ppm in the gas concentration and operating to temperatures of 23, 100, 200, and 300 C were studied. Prepared films of pure SnO{sub 2} were modified superficially with 1, 3, 5 and 10 layers of the catalyst Cu (SnO{sub 2}:Cu) with the purpose of studying the effect on the sensor capacity of the gas CO by part of the films SnO{sub 2}:Cu. Using the changes in the electric properties of the films with the incorporation of the different copper layers and experimental conditions, the sensor modifications of the gas CO were evaluated. To complete this study, was realized a characterization of the superficial morphology of the films by scanning electron microscopy and atomic force microscopy, equally was studied their structure and their electric and optical properties. (Author)

Neutrino spectrum from SN 1987A and from cosmic supernovae

International Nuclear Information System (INIS)

Yueksel, Hasan; Beacom, John F.

2007-01-01

The detection of neutrinos from SN 1987A by the Kamiokande-II and Irvine-Michigan-Brookhaven detectors provided the first glimpse of core collapse in a supernova, complementing the optical observations and confirming our basic understanding of the mechanism behind the explosion. One long-standing puzzle is that, when fitted with thermal spectra, the two independent detections do not seem to agree with either each other or typical theoretical expectations. We assess the compatibility of the two data sets in a model-independent way and show that they can be reconciled if one avoids any bias on the neutrino spectrum stemming from theoretical conjecture. We reconstruct the neutrino spectrum from SN 1987A directly from the data through nonparametric inferential statistical methods and present predictions for the diffuse supernova neutrino background based on SN 1987A data. We show that this prediction cannot be too small (especially in the 10-18 MeV range), since the majority of the detected events from SN 1987A were above 18 MeV (including 6 events above 35 MeV), suggesting an imminent detection in operational and planned detectors

The Type II supernovae 2006V and 2006au: two SN 1987A-like events

DEFF Research Database (Denmark)

Taddia, F.; Stritzinger, M. D.; Sollerman, J.

2012-01-01

1987A. Methods. Optical and near-infrared (NIR) light curves, and optical spectroscopy of SNe 2006V and 2006au are presented. These observations are compared to those of SN 1987A, and are used to estimate properties of their progenitors. Results. Both objects exhibit a slow rise to maximum and light...

Synthesis, characterization and photocatalytic performance of SnS nanofibers and SnSe nanofibers derived from the electrospinning-made SnO{sub 2} nanofibers

Energy Technology Data Exchange (ETDEWEB)

Cheng, Li; Li, Dan; Dong, Xiangting; Ma, Qianli; Yu, Wensheng; Wang, Xinlu; Yu, Hui; Wang, Jinxian; Liu, Guixia, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

2017-11-15

SnO{sub 2} nanofibers were fabricated by calcination of the electrospun PVP/SnCl{sub 4} composite nanofibers. For the first time, SnS nanofibers and SnSe nanofibers were successfully synthesized by double crucible sulfurization and selenidation methods via inheriting the morphology of SnO{sub 2} nanofibers used as precursors, respectively. X-ray diffraction (XRD) analysis shows SnS nanofibers and SnSe nanofibers are respectively pure orthorhombic phase with space group of Pbnm and Cmcm. Scanning electron microscope (SEM) observation indicates that the diameters of SnS nanofibers and SnSe nanofibers are respectively 140.54±12.80 nm and 96.52±14.17 nm under the 95 % confidence level. The photocatalytic activities of samples were studied by using rhodamine B (Rh B) as degradation agent. When SnS or SnSe nanofibers are employed as the photocatalysts, the respective degradation rates of Rh B solution under the ultraviolet light irradiation after 200 min irradiation are 92.55 % and 92.86 %. The photocatalytic mechanism and formation process of SnS and SnSe nanofibers are also provided. More importantly, this preparation technique is of universal significance to prepare other metal chalcogenides nanofibers. (author)

Ceramic insulation for superconducting Nb{sub 3}Sn cables; Isolation ceramique pour cables supraconducteurs en Nb{sub 3}Sn

Energy Technology Data Exchange (ETDEWEB)

Puigsegur, A

2005-01-15

Nb{sub 3}Sn is the best superconductor candidate for the realization of high field magnets (>11 Tesla), its implementation remains delicate because of the great brittleness of material after the heat treatment necessary to the formation of Nb{sub 3}Sn compounds. The conventional insulation for Nb{sub 3}Sn requires to perform, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We have proposed an innovating ceramic insulation deposited directly on the unreacted conducting cable. After the heat treatment of the niobium tin, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. After a rheological study, to characterize the impregnated suspension, we have shown that using this insulation in a coil manufacture process does not affect the electrical properties of the Nb{sub 3}Sn wires. A solenoid of small dimensions was tested with success in high external magnetic fields and has produced a magnetic field of 3.8 T under 740 A. (author)

Sn-In-Ag phase equilibria and Sn-In-(Ag)/Ag interfacial reactions

International Nuclear Information System (INIS)

Chen Sinnwen; Lee Wanyu; Hsu Chiaming; Yang Chingfeng; Hsu Hsinyun; Wu Hsinjay

2011-01-01

Research highlights: → Thermodynamic models of Sn-In and Sn-In-Ag are developed using the CALPHAD approach. → Reaction layer in the Sn-In-(Ag)/Ag couples at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. → Reactions in the Sn-20 wt%In-2.8 wt%Ag/Ag couples are faster than those in the Sn-20 wt%In/Ag couples. - Abstract: Experimental verifications of the Sn-In and Sn-In-Ag phase equilibria have been conducted. The experimental measurements of phase equilibria and thermodynamic properties are used for thermodynamic modeling by the CALPHAD approach. The calculated results are in good agreement with experimental results. Interfacial reactions in the Sn-In-(Ag)/Ag couples have been examined. Both Ag 2 In and AgIn 2 phases are formed in the Sn-51.0 wt%In/Ag couples reacted at 100 and 150 deg. C, and only the Ag 2 In phase is formed when reacted at 25, 50 and 75 deg. C. Due to the different growth rates of different reaction phases, the reaction layer at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. In the Sn-20.0 wt%In/Ag couples, the ζ phase is formed at 250 deg. C and ζ/AgIn 2 phases are formed at 125 deg. C. Compared with the Sn-20 wt%In/Ag couples, faster interfacial reactions are observed in the Sn-20.0 wt%In-2.8 wt%Ag/Ag couples, and minor Ag addition to Sn-20 wt%In solder increases the growth rates of the reaction phases.

Magnetic behaviour of cerium in Ce2 Sn5 and Ce3 Sn7, surstructures of Ce Sn3

International Nuclear Information System (INIS)

Stunault, A.

1988-07-01

The compound studied, Ce 2 Sn 5 and Ce 3 Sn 7 are both orthorhombic, surstructure of cubic Ce Sn 3 . Magnetic susceptibility measurements show in both compounds an antiferromagnetic order at low temperature and magnetization shows a high anisotropy. Magnetization densities are determined by polarized neutron diffraction. The cerium site which has two Ce atoms as nearest neighbourgs carries all the magnetism in both structures. For Ce 2 Sn 5 moments are directed as the high magnetization axis and structure is modulated. Ce 3 Sn 7 presents a simple antiferromagnetic order but moment are directed as low magnetization axis. Various transitions towards a ferromagnetic order are presented. Results are interpreted by measuring the difference between energy levels of crystalline field. A model of crystalline field and isotrope exchange agrees well with Ce 3 Sn 7 , but for Ce 2 Sn 7 it is necessary to reduce the magnetic moment which is typical of the Kondo effect [fr

Refractive index extraction and thickness optimization of Cu2ZnSnSe4 thin film solar cells

NARCIS (Netherlands)

ElAnzeery, H.; El Daif, O.; Buffière, M.; Oueslati, S.; Ben Messaoud, K.; Agten, D.; Brammertz, G.; Guindi, R.; Kniknie, B.; Meuris, M.; Poortmans, J.

2015-01-01

Cu2nSnSe4 (CZTSe) thin film solar cells are promising emergent photovoltaic technologies based on low-bandgap absorber layer with high absorption coefficient. To reduce optical losses in such devices and thus improve their efficiency, numerical simulations of CZTSe solar cells optical

Characterization of ZnO:SnO{sub 2} (50:50) thin film deposited by RF magnetron sputtering technique

Energy Technology Data Exchange (ETDEWEB)

Cynthia, S. R.; Sanjeeviraja, C.; Ponmudi, S. [Department of Physics, Alagappa Chettiar College of Engineering and Technology, Karaikudi-630004 (India); Sivakumar, R., E-mail: krsivakumar1979@yahoo.com [Directorate of Distance Education, Alagappa University, Karaikudi-630004 (India)

2016-05-06

Zinc oxide (ZnO) and tin oxide (SnO{sub 2}) thin films have attracted significant interest recently for use in optoelectronic application such as solar cells, flat panel displays, photonic devices, laser diodes and gas sensors because of their desirable electrical and optical properties and wide band gap. In the present study, thin films of ZnO:SnO{sub 2} (50:50) were deposited on pre-cleaned microscopic glass substrate by RF magnetron sputtering technique. The substrate temperature and RF power induced changes in structural, surface morphological, compositional and optical properties of the films have been studied.

Kodak phase-change media for optical tape applications

Science.gov (United States)

Tyan, Yuan-Sheng; Preuss, Donald R.; Olin, George R.; Vazan, Fridrich; Pan, Kee-Chuan; Raychaudhuri, Pranab. K.

1993-01-01

The SbInSn phase-change write-once optical medium developed by Eastman Kodak Company is particularly suitable for development into the next generation optical tape media. Its performance for optical recording has already been demonstrated in some of the highest performance optical disk systems. Some of the key performance features are presented.

Accurate beacon positioning method for satellite-to-ground optical communication.

Science.gov (United States)

Wang, Qiang; Tong, Ling; Yu, Siyuan; Tan, Liying; Ma, Jing

2017-12-11

In satellite laser communication systems, accurate positioning of the beacon is essential for establishing a steady laser communication link. For satellite-to-ground optical communication, the main influencing factors on the acquisition of the beacon are background noise and atmospheric turbulence. In this paper, we consider the influence of background noise and atmospheric turbulence on the beacon in satellite-to-ground optical communication, and propose a new locating algorithm for the beacon, which takes the correlation coefficient obtained by curve fitting for image data as weights. By performing a long distance laser communication experiment (11.16 km), we verified the feasibility of this method. Both simulation and experiment showed that the new algorithm can accurately obtain the position of the centroid of beacon. Furthermore, for the distortion of the light spot through atmospheric turbulence, the locating accuracy of the new algorithm was 50% higher than that of the conventional gray centroid algorithm. This new approach will be beneficial for the design of satellite-to ground optical communication systems.

Collaborative Assembly Operation between Two Modular Robots Based on the Optical Position Feedback

Directory of Open Access Journals (Sweden)

Liying Su

2009-01-01

Full Text Available This paper studies the cooperation between two master-slave modular robots. A cooperative robot system is set up with two modular robots and a dynamic optical meter-Optotrak. With Optotrak, the positions of the end effectors are measured as the optical position feedback, which is used to adjust the robots' end positions. A tri-layered motion controller is designed for the two cooperative robots. The RMRC control method is adopted to adjust the master robot to the desired position. With the kinematics constraints of the two robots including position and pose, joint velocity, and acceleration constraints, the two robots can cooperate well. A bolt and nut assembly experiment is executed to verify the methods.

Terbium doped SnO2 nanoparticles as white emitters and SnO2:5Tb/Fe3O4 magnetic luminescent nanohybrids for hyperthermia application and biocompatibility with HeLa cancer cells.

Science.gov (United States)

Singh, Laishram Priyobarta; Singh, Ningthoujam Premananda; Srivastava, Sri Krishna

2015-04-14

SnO2:5Tb (SnO2 doped with 5 at% Tb(3+)) nanoparticles were synthesised by a polyol method and their luminescence properties at different annealing temperatures were studied. Characterization of nanomaterials was done by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). XRD studies indicate that the prepared nanoparticles were of tetragonal structures. Upon Tb(3+) ion incorporation into SnO2, Sn(4+) changes to Sn(2+) and, on annealing again at higher temperature, Sn(2+) changes to Sn(4+). The prepared nanoparticles were spherical in shape. Sn-O vibrations were found from the FTIR studies. In photoluminescence studies, the intensity of the emission peaks of Tb(3+) ions increases with the increase of annealing temperature, and emission spectra lie in the region of white emission in the CIE diagram. CCT calculations show that the SnO2:5Tb emission lies in cold white emission. Quantum yields up to 38% can be obtained for 900 °C annealed samples. SnO2:5Tb nanoparticles were well incorporated into the PVA polymer and such a material incorporated into the polymer can be used for display devices. The SnO2:5Tb/Fe3O4 nanohybrid was prepared and investigated for hyperthermia applications at different concentrations of the nanohybrid. This achieves a hyperthermia temperature (42 °C) under an AC magnetic field. The hybrid nanomaterial SnO2:5Tb/Fe3O4 was found to exhibit biocompatibility with HeLa cells (human cervical cancer cells) at concentrations up to 74% for 100 μg L(-1). Also, this nanohybrid shows green emission and thus it will be helpful in tracing magnetic nanoparticles through optical imaging in vivo and in vitro application.

Morphology and optical properties of ternary Zn-Sn-O semiconductor nanowires with catalyst-free growth

Energy Technology Data Exchange (ETDEWEB)

Liang, Yuan-Chang, E-mail: yuanvictory@gmail.com [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China); Huang, Chiem-Lum; Hu, Chia-Yen; Deng, Xian-Shi; Zhong, Hua [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China)

2012-10-05

Highlights: Black-Right-Pointing-Pointer Zn{sub 2}SnO{sub 4} nanowires with various morphologies were successfully synthesized by thermal evaporation. Black-Right-Pointing-Pointer The as-synthesized Zn{sub 2}SnO{sub 4} nanowires have a face-centered cubic crystal structure. Black-Right-Pointing-Pointer Thermal annealing of Zn{sub 2}SnO{sub 4} nanowires changes the properties of the visible emission band. - Abstract: This study reports the synthesis of Zn{sub 2}SnO{sub 4} (ZTO) nanowires with various morphologies using thermal evaporation without a metal catalyst. X-ray diffraction patterns show that the structure of the as-synthesized ZTO nanowires is a face-centered cubic spinel phase. Scanning electron microscopy images exhibit that the as-synthesized nanowires have various morphologies, and homogeneously cover the area of interest. High-resolution transmittance electron microscopy reveals that these ZTO nanowires have single crystalline microstructures with four morphologies. The results of low-temperature cathodoluminescence (CL) measurements show the crystal defects of oxygen vacancies and interstitials may contribute to blue-green and yellow-orange emissions, respectively, for the as-synthesized single nanowire. This study also discusses the effects of thermal annealing under oxygen-rich and reducing ambient on the CL properties of the single ZTO nanowire.

Effects of Third Constituent on As-cast Microstructures and Mechanical Properties of Mg-Sn Alloy

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HUANG Zheng-hua

2016-06-01

Full Text Available As-cast microstructures and phase compositions of Mg-3.52Sn-xM and Mg-6.54Sn-xM (M=Al, Zn, Nd, Gd alloys were investigated by optical microscope, scanning electron microscope and X-ray diffraction. Meanwhile, the tensile mechanical properties were tested. The results show that the coarse dendrite is refined slightly and few block Mg2Sn phase still exists when 0.91% (mass fraction, the same below Al and 1.03%Zn are added into Mg-3.52Sn alloy, respectively. When 0.92%Nd and 1.10%Gd are added respectively, the dendrite weakens obviously and many small block or fine short rod-shaped compounds Mg-Sn-Nd and Mg-Sn-Gd can be observed. When 0.93%Al and 1.08%Zn are added into Mg-6.54Sn respectively, the dendrite is refined obviously and Mg2Sn phase tending to precipitate in the state of continuous net begins to break slightly. When 0.86%Nd and 0.74%Gd are added respectively, the dendrite weakens significantly and Mg2Sn phase has already broken into small block completely or significantly. Meanwhile, many small block or fine short rod-shaped compounds Mg-Sn-Nd and Mg-Sn-Gd can also be observed. The respective addition of about 1%Al and Zn into the Mg-3.52Sn and Mg-6.54Sn binary alloys respectively can enhance the tensile mechanical properties namely the ambient and elevated temperatures effectively, while the respective addition of about 1%Nd and Gd cannot enhance them effectively, especially for the addition of Nd.

Spectroscopic ellipsometry study of Cu2ZnSnS4 bulk poly-crystals

Science.gov (United States)

Levcenko, S.; Hajdeu-Chicarosh, E.; Garcia-Llamas, E.; Caballero, R.; Serna, R.; Bodnar, I. V.; Victorov, I. A.; Guc, M.; Merino, J. M.; Pérez-Rodriguez, A.; Arushanov, E.; León, M.

2018-04-01

The linear optical properties of Cu2ZnSnS4 bulk poly-crystals have been investigated using spectroscopic ellipsometry in the range of 1.2-4.6 eV at room temperature. The characteristic features identified in the optical spectra are explained by using the Adachi analytical model for the interband transitions at the corresponding critical points in the Brillouin zone. The experimental data have been modeled over the entire spectral range taking into account the lowest E0 transition near the fundamental absorption edge and E1A and E1B higher energy interband transitions. In addition, the spectral dependences of the refractive index, extinction coefficient, absorption coefficient, and normal-incidence reflectivity values have been accurately determined and are provided since they are essential data for the design of Cu2ZnSnS4 based optoelectronic devices.

Research on Cu2ZnSnTe4 crystals and heterojunctions based on such crystals

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Kovaliuk T. T.

2015-12-01

Full Text Available The paper reports on the results of the studies of magnetic, kinetic and optical properties of Cu2ZnSnTe4 crystals. The Cu2ZnSnTe4 crystals showed diamagnetic properties (the magnetic susceptibility almost independent of the magnetic field and temperature. The Cu2ZnSnTe4 crystals possessed p-type of conductivity and the Hall coefficient was independent on temperature. The temperature dependence of the electrical conductivity of the Cu2ZnSnTe4 crystal shows metallic character, i. e. decreases with the increase of temperature, that is caused by the lower charge carrier mobility at higher temperature. Thermoelectric power of the samples ispositive that also indicates on the prevalence of p-type conductivity. Heterojunctions n-TiN/p-Cu2ZnSnTe4, n-TiO2/p-Cu2ZnSnTe4 and n-MoO/p-Cu2ZnSnTe4 were fabricated by the reactive magnetron sputtering of TiN, TiO2 and MoOx thin films, respectively, onto the substrates made of the Cu2ZnSnTe4 crystals. The dominating current transport mechanisms in the n-TiN/p-Cu2ZnSnTe4 and n-TiO2/p-Cu2ZnSnTe4 heterojunctions were established to be the tunnel-recombination mechanism at forward bias and tunneling at reverse bias.

Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

Energy Technology Data Exchange (ETDEWEB)

Anjos, D.M. dos; Hahn, F.; Leger, J.M.; Kokoh, K.B. [Universite de Poitiers, Poitiers Cedex (France). Centre National de la Recherche Scientifique (CNRS). Equipe Electrocatalyse; Tremiliosi-Filho, G. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica

2008-07-01

Ethanol oxidation has been studied on Pt-Sn and Pt-Sn-W electrodes prepared in an arc-melting furnace. Different electrochemical techniques like cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of these materials. The electro-oxidation process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. Experimental results indicated that Pt-Sn and Pt-Sn-W alloys are able to oxidize ethanol mainly to acetaldehyde and acetic acid. Adsorbed CO was also detected, demonstrating the viability of splitting the C-C bond in the ethanol molecule during the oxidation process. The adsorbed CO was further oxidized to CO{sub 2}.This reaction product was clearly detected by SNIFTIRS. Pt-Sn-W catalyst showed a better electrochemical performance than Pt-Sn that, in it turn, is better than Pt-alone. (author)

K2 ZnSn3 Se8 : A Non-Centrosymmetric Zinc Selenidostannate(IV) Featuring Interesting Covalently Bonded [ZnSn3 Se8 ]2- Layer and Exhibiting Intriguing Second Harmonic Generation Activity.

Science.gov (United States)

Zhou, Molin; Jiang, Xingxing; Yang, Yi; Guo, Yangwu; Lin, Zheshuai; Yao, JJiyong; Wu, Yicheng

2017-06-19

Non-centrosymmetric zinc selenidostannate(IV) K 2 ZnSn 3 Se 8 was synthesized. It features interesting covalently bonded [ZnSn 3 Se 8 ] 2- layers with K + cations filling in the interlayer voids. The phonon spectrum was calculated to clarify its structural stability. Based on the X-ray diffraction data along with the Raman spectrum, the major bonding features of the title compound were identified. According to the UV/vis-NIR spectroscopy, K 2 ZnSn 3 Se 8 possesses a typical direct band gap of 2.10 eV, which is in good agreement with the band structure calculations. Moreover, our experimental measurements and detailed theoretical calculations reveal that K 2 ZnSn 3 Se 8 is a new phase-matchable nonlinear optical material with a powder second harmonic generation (SHG) signal about 0.6 times of that of AgGaS 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

THE UNUSUALLY LUMINOUS EXTRAGALACTIC NOVA SN 2010U

International Nuclear Information System (INIS)

Czekala, Ian; Berger, E.; Chornock, R.; Marion, G. H.; Margutti, R.; Challis, P.; Pastorello, A.; Botticella, M. T.; Ergon, M.; Sollerman, J.; Smartt, S.; Vinkó, J.; Wheeler, J. C.

2013-01-01

We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast decline (t 2 = 3.5 ± 0.3 days) from maximum light (M V = –10.2 ± 0.1 mag), placing SN 2010U in the top 0.5% of the most luminous novae ever observed. We find typical ejecta velocities of ≈1100 km s –1 and that SN 2010U shares many spectral and photometric characteristics with two other fast and luminous Fe II type novae, including Nova LMC 1991 and M31N-2007-11d. For the extreme luminosity of this nova, the maximum magnitude versus rate of decline relationship indicates a massive white dwarf (WD) progenitor with a low pre-outburst accretion rate. However, this prediction is in conflict with emerging theories of nova populations, which predict that luminous novae from massive WDs should preferentially exhibit an alternate spectral type (He/N) near maximum light.

Influence of geometrical thickness of SnO2 based photoanode on the performance of Eosin-Y dye sensitized solar cell

Science.gov (United States)

Arote, Sandeep; Rajendra Prasad, M. B.; Tabhane, Vilas; Pathan, Habib

2015-11-01

In the present study, efforts have been taken to tune the optical parameters of SnO2 photoelectrode film to enhance the performance SnO2 based Dye Sensitized Solar Cell (DSSC). Influence of geometrical thickness of SnO2 based photoelectrode on light scattering magnitude and light harvesting capability was investigated using optical diffused reflectance and electrochemical impedance measurements. The short circuit current density (JSC) of the DSSC assembled using these photoanodes was apparently the decisive photovoltaic parameter in finalizing its photovoltaic efficiency (η). The variation in the light harvesting efficiency and the electron transfer yield were studied as a function of thickness of the photoanode by virtue of the light scattering magnitude in the films. These two factors appeared to have profoundly influenced JSC and so the photovoltaic performance of DSSC.

Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires

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E. Karageorgou

2014-11-01

Full Text Available SnO2 and Sn:In2O3 nanowires were grown on Si(001, and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current–voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires were obtained by depositing copper and post-growth processing under H2S between 100 and 500 °C. These consist mainly of tetragonal rutile SnO2 and cubic bixbyite In2O3. We observe photoluminescence at 3.65 eV corresponding to band edge emission from SnO2 quantum dots in the Cu2SnS3/SnO2 nanowires due to electrostatic confinement. The Cu2SnS3/SnO2 nanowires assemblies had resistances of 100 Ω similar to CuInS2/In2O3 nanowires which exhibited photoluminescence at 3.0 eV.

Clinical results of sentinel lymph node (SN) biopsy for oral cancer. Relationship between SN localization and metastasis in tongue cancer

International Nuclear Information System (INIS)

Shintani, Satoru; Nakashiro, Koh-ichi; Hino, Satoshi; Terakado, Nagaaki; Hamakawa, Hiroyuki

2005-01-01

Attempts were made to detect micrometastasis in N0 neck of oral cancer patients using sentinel lymph node (SN) biopsy (SNB). We previously described our approach to identify SN using a radioisotope ( 99m Tc-Tin colloid)-guided and dye-guided method. Micrometastases were detected by means of serial sections and real-time polymerase chain reaction (PCR) based on squamous cell carcinoma (SCC) antigen mRNA. In this study, we evaluated the radiolocalization of SN and identification of metastatic lymph node in N0 oral cancer patients. The positive rate of metastatic lymph node in N0 oral cancer was 35% and the diagnostic sensitivity of SNB was 95%. The SNB detected subclinical metastases in 4 of 10 N0 patients with tongue cancer. Moreover, in 3 of these 4 cases, all metastatic lymph nodes consisted with SNs. Postoperative cervical metastasis was observed in a patient whose SNB was negative. While more experience is needed, we believe the SN concept for tongue cancer is established, and practical application in clinical settings is anticipated. (author)

Optical and electrical properties study of sol-gel derived Cu2ZnSnS4 thin films for solar cells

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B. L. Guo

2014-09-01

Full Text Available The fabrication of environmental-friendly Cu2ZnSnS4 (CZTS thin films with pure kesterite phase is always a challenge to researchers in the field of solar cells. We introduce a simple non-vacuum sol-gel method to fabricate kesterite CZTS films. Ethylenediamine is used as the chelating agent and stabilizer and plays an important role in preparing stable precursor. X-ray diffraction, Raman and scanning electron microscopy studies suggest that the microstructure and optical properties of CZTS films depend strongly on annealing temperatures. The temperature dependence of conductivity of 500 °C annealed CZTS film shows that the Mott law dominates in the low temperature region and thermionic emission is predominant at high temperatures.

Phase diagram of SnTe-CdSe cross-section of SnTe+CdSe reversible SnSe+CdTe ternary reciprocal system

International Nuclear Information System (INIS)

Dubrovin, I.V.; Budennaya, L.D.; Mizetskaya, I.B.; Sharkina, Eh.V.

1986-01-01

Phase equilibrium diagram of SnTe-CdSe cross-section of Sn, Cd long Te, Se ternary reciprocal system is investigated using the methods of differential thermal, X-ray phase, and microstructural analyses. Maximum length of solid solutions on the base of SnTe corresponds to approximately 14 mol.% at 1050 K and approximately 3 mol.% of CdSe at 670 K. Region of solid solutions on the base of CdSe corresponds to less than 1 mol.% of SnTe at room temperature. SnTe-CdSe cross-section is not a quasibinar one. Equilibrium is shifted to the left in the SnTe+CdSe reversible SnSe+CdTe reciprocal system

Cu2ZnSnS4 solar cells fabricated by short-term sulfurization of sputtered Sn/Zn/Cu precursors under an H2S atmosphere

International Nuclear Information System (INIS)

Emrani, Amin; Rajbhandari, Pravakar P.; Dhakal, Tara P.; Westgate, Charles R.

2015-01-01

Synthesis of Cu 2 ZnSnS 4 (CZTS) thin films by short-term sulfurization of sputtered Sn/Zn/Cu precursors under ambient H 2 S is studied. The effect of the sulfurization processes on the film morphology, surface roughness, composition of the CZTS, and the crystallinity was investigated by using scanning electron microscopy, optical profiler, energy dispersive spectroscopy, and X-ray diffraction respectively. To further explore the CZTS layer, the following additional layers were deposited to complete the solar cells: CdS with chemical bath deposition; ZnO and Al 2 O 3 -doped ZnO with RF magnetron deposition; and, silver fingers as the front contact as the last layer. The optical and morphological properties of the CZTS films were investigated and compared. Subsequently, the electrical characteristics and the efficiencies of the regarding solar cells were analyzed. A maximum efficiency of 3.8% has been obtained for the fast sulfurization (30 min at 580 °C) and finally, the performance is compared with our best cell fabricated through the more common slow annealing. - Highlights: • Development of Cu 2 ZnSnS 4 (CZTS) solar cells using elemental metal sputtering • 112-oriented CZTS films with well-defined morphology obtained • Reported efficiency of 3.8% for a short-term annealing (less than 30 min) under ambient H 2 S • A detailed comparison between the fast and the more common slow annealing is reported

Tuning of optical and electrical properties of wide band gap Fe:SnO{sub 2}/Li:NiO p-n junctions using 80 MeV oxygen ion beam

Energy Technology Data Exchange (ETDEWEB)

Mistry, Bhaumik V.; Joshi, U.S. [Gujarat University, Department of Physics, School of Sciences, Ahmedabad (India); Avasthi, D.K. [Inter University Accelerator Centre, New Delhi (India)

2016-12-15

Electrical and optical properties of pristine and swift heavy ion (SHI) irradiated p-n junction diode have been investigated for advanced electronics application. Fe:SnO{sub 2}/Li:NiO p-n junction was fabricated by using pulsed laser deposition on c-sapphire substrate. The optical band gaps of Fe:SnO{sub 2} and Li:NiO films were obtained to be 3.88 and 3.37 eV, respectively. The current-voltage characteristics of the oxide-based p-n junction showed a rectifying behaviour with turn-on voltage of 0.95 V. The oxide-based p-n junction diode was irradiated to 80 MeV O{sup +6} ions with 1 x 10{sup 12} ions/cm{sup 2} fluence. Decrease in grain size due to SHI irradiation is confirmed by the grazing angle X-ray diffraction and atomic force microscopy. In comparison with the pristine p-n junction diode, O{sup +6} ion irradiated p-n junction diode shows the increase of surface roughness and decrease of percentage transmittance in visible region. For irradiated p-n junction diode, current-voltage curve has still rectifying behaviour but exhibits lower turn-on voltage than that of virgin p-n junction diode. (orig.)

Frequency of Application of AmF/NaF/SnCl2 Solution and Its Potential in Inhibiting the Progression of Erosion in Human Dental Enamel - An In Vitro Study.

Science.gov (United States)

da Silva, Camilla Vieira; Nazello, Jessica Laporta; de Freitas, Patricia Moreira

To evaluate whether increasing the frequency of its use can enhance the protective effect of AmF/NaF/SnCl2 solution against dental erosion. Sixty human enamel samples were obtained from sound human third molars, and after the formation of incipient erosive lesions (1% citric acid, pH 4.0, for 3 min), they were divided into five treatment groups (n = 12): G1 - deionised water (negative control); G2 - NaF solution (positive control) once a day; G3 - NaF solution (positive control) twice a day; G4 - AmF/NaF/SnCl2 solution once a day; G5 - AmF/NaF/SnCl2 solution twice a day. The samples were then subjected to 5 days of erosive cycling through 6 daily immersions (2 min each) in citric acid solution (0.05 M, pH 2.6). At the end of erosive cycling, surface wear was determined by means of optical profilometry. One-way ANOVA showed that the surface wear was affected by surface treatments (p enamel surface loss and its use twice a day potentiated its anti-erosive effect.

ZnO doped SnO2 nanoparticles heterojunction photo-catalyst for environmental remediation

International Nuclear Information System (INIS)

Lamba, Randeep; Umar, Ahmad; Mehta, S.K.; Kansal, Sushil Kumar

2015-01-01

ZnO doped SnO 2 nanoparticles were synthesized by facile and simple hydrothermal technique and used as an effective photocatalyst for the photocatalytic degradation of harmful and toxic organic dye. The prepared nanoparticles were characterized in detail using different techniques for morphological, structural and optical properties. The characterization results revealed that the synthesized nanoparticles possess both crystal phases of tetragonal rutile phase of pure SnO 2 and wurtzite hexagonal phase of ZnO. In addition, the nanoparticles were synthesized in very high quantity with good crystallinity. The photocatalytic activity of prepared nanoparticles was evaluated by the photocatalytic degradation of methylene blue (MB) dye. Detailed photocatalytic experiments based on the effects of irradiation time, catalyst dose and pH were performed and presented in this paper. The detailed photocatalytic experiments revealed that the synthesized ZnO doped SnO 2 nanoparticles heterojunction photocatalyst exhibit best photocatalytic performance when the catalyst dose was 0.25 g/L and pH = 10. ZnO doped SnO 2 nanoparticles heterojunction photocatalyst was also compared with commercially available TiO 2 (PC-50), TiO 2 (PC-500) and SnO 2 and interestingly ZnO doped SnO 2 nanoparticles exhibited superior photocatalytic performance. The presented work demonstrates that the prepared ZnO doped SnO 2 nanoparticles are promising material for the photocatalytic degradation of organic dyes and toxic chemicals. - Highlights: • Synthesis of well-crystalline ZnO-doped SnO 2 nanoparticles. • Excellent morphological, crystalline and photoluminescent properties. • Efficient environmental remediation using ZnO-doped SnO 2 nanoparticles.

Shape Engineering Driven by Selective Growth of SnO2 on Doped Ga2O3 Nanowires.

Science.gov (United States)

Alonso-Orts, Manuel; Sánchez, Ana M; Hindmarsh, Steven A; López, Iñaki; Nogales, Emilio; Piqueras, Javier; Méndez, Bianchi

2017-01-11

Tailoring the shape of complex nanostructures requires control of the growth process. In this work, we report on the selective growth of nanostructured tin oxide on gallium oxide nanowires leading to the formation of SnO 2 /Ga 2 O 3 complex nanostructures. Ga 2 O 3 nanowires decorated with either crossing SnO 2 nanowires or SnO 2 particles have been obtained in a single step treatment by thermal evaporation. The reason for this dual behavior is related to the growth direction of trunk Ga 2 O 3 nanowires. Ga 2 O 3 nanowires grown along the [001] direction favor the formation of crossing SnO 2 nanowires. Alternatively, SnO 2 forms rhombohedral particles on [110] Ga 2 O 3 nanowires leading to skewer-like structures. These complex oxide structures were grown by a catalyst-free vapor-solid process. When pure Ga and tin oxide were used as source materials and compacted powders of Ga 2 O 3 acted as substrates, [110] Ga 2 O 3 nanowires grow preferentially. High-resolution transmission electron microscopy analysis reveals epitaxial relationship lattice matching between the Ga 2 O 3 axis and SnO 2 particles, forming skewer-like structures. The addition of chromium oxide to the source materials modifies the growth direction of the trunk Ga 2 O 3 nanowires, growing along the [001], with crossing SnO 2 wires. The SnO 2 /Ga 2 O 3 junctions does not meet the lattice matching condition, forming a grain boundary. The electronic and optical properties have been studied by XPS and CL with high spatial resolution, enabling us to get both local chemical and electronic information on the surface in both type of structures. The results will allow tuning optical and electronic properties of oxide complex nanostructures locally as a function of the orientation. In particular, we report a dependence of the visible CL emission of SnO 2 on its particular shape. Orange emission dominates in SnO 2 /Ga 2 O 3 crossing wires while green-blue emission is observed in SnO 2 particles attached to Ga 2

The curious case of SN 2011dn: A very peculiar type Ia supernova?

Science.gov (United States)

Rachubo, Alisa

Type Ia supernovae (SNe Ia) are excellent cosmological distance indicators due to the uniformity in their light curves, which led to the major discovery of the accelerated expansion of the universe. However, SNe Ia are not so uniform as one may expect, as there are many peculiar SNe Ia that exhibit differences in their photometric and spectroscopic behavior from normal SNe Ia. One of the goals of supernova cosmology today is to produce a cleaner sample of SNe Ia without these peculiar SNe Ia. Here we consider SN 2011dn, a peculiar SN Ia candidate. In 2011, Salvo, et al. carried out a preliminary analysis of a subset of the data prescribed here, and identified spectral and photometric peculiarities in this object's evolution that warranted further analysis. Here, we present a complete re-reduction and reanalysis of B, V,R, and I photometry of SN 2011dn obtained at Mount Laguna Observatory, spanning from 7 days before maximum light in B to 88 days past maximum light. In addition, we also consider total flux spectra from 9 days before maximum light to 4 days after maximum light, along with ultraviolet (UV) photometry obtained with the Swift telescope. From SN 2011dn's optical spectra, we find that SN 2011dn most closely resembles a SN 1991T-like type Ia supernova ('91T-like SN Ia). Such SNe Ia are typically more luminous than normal SNe Ia, and possess broader (i.e., they decline less rapidly than normal from maximum light) light curves. Their Deltam15(B) (drop in B magnitude 15 days after maximum light) are typically significantly less than the canonical value of 1.1, and can be as low as 0.8. In the earlier preliminary analysis, Salvo et al. measured a surprisingly high Deltam15(B) value for SN 2011dn, of ˜ 1.1. Since SN 2011dn was embedded in UGC 11501 (its host galaxy), however, it is possible that some of the light from the host galaxy was included in the photometric aperture, resulting in inaccurate photometric measurements. Here, in order to better isolate the

Quaternary selenostannates Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} and AGaSnSe{sub 4} (A=K, Rb, and Cs) through rapid cooling of melts. Kinetics versus thermodynamics in the polymorphism of AGaSnSe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Hwang, S -J; Iyer, R G; Kanatzidis, M G

2004-10-01

The quaternary alkali-metal gallium selenostannates, Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} and AGaSnSe{sub 4} (A=K, Rb, and Cs), were synthesized by reacting alkali-metal selenide, Ga, Sn, and Se with a flame melting-rapid cooling method. Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} crystallizes in the non-centrosymmetric space group C2 with cell constants a=13.308(3) A, b=7.594(2) A, c=13.842(3) A, {beta}=118.730(4) deg., V=1226.7(5) A{sup 3}. {alpha}-KGaSnSe{sub 4} crystallizes in the tetragonal space group I4/mcm with a=8.186(5) A and c=6.403(5) A, V=429.1(5) A{sup 3}. {beta}-KGaSnSe{sub 4} crystallizes in the space group P2{sub 1}/c with cell constants a=7.490(2) A, b=12.578(3) A, c=18.306(5) A, {beta}=98.653(5) deg., V=1705.0(8) A{sup 3}. The unit cell of isostructural RbGaSnSe{sub 4} is a=7.567(2) A, b=12.656(3) A, c=18.277(4) A, {beta}=95.924(4) deg., V=1741.1(7) A{sup 3}. CsGaSnSe{sub 4} crystallizes in the orthorhombic space group Pmcn with a=7.679(2) A, b=12.655(3) A, c=18.278(5) A, V=1776.1(8) A{sup 3}. The structure of Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} consists of a polar three-dimensional network of trimeric (Sn,Ga){sub 3}Se{sub 9} units with Na atoms located in tunnels. The AGaSnSe{sub 4} possess layered structures. The compounds show nearly the same Raman spectral features, except for Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6}. Optical band gaps, determined from UV-Vis spectroscopy, range from 1.50 eV in Na{sub 2-x}Ga{sub 2-x}Sn{sub 1+x}Se{sub 6} to 1.97 eV in CsGaSnSe{sub 4}. Cooling of the melts of KGaSnSe{sub 4} and RbGaSnSe{sub 4} produces only kinetically stable products. The thermodynamically stable product is accessible under extended annealing, which leads to the so-called {gamma}-form (BaGa{sub 2}S{sub 4}-type) of these compounds.

Laser induced forward transfer of SnO2 for sensing applications using different precursors systems

Science.gov (United States)

Mattle, Thomas; Hintennach, Andreas; Lippert, Thomas; Wokaun, Alexander

2013-02-01

This paper presents the transfer of SnO2 by laser induced forward transfer (LIFT) for gas sensor applications. Different donor substrates of SnO2 with and without triazene polymer (TP) as a dynamic release layer were prepared. Transferring these films under different conditions were evaluated by optical microscopy and functionality. Transfers of sputtered SnO2 films do not lead to satisfactory results and transfers of SnO2 nanoparticles are difficult. Transfers of SnO2 nanoparticles can only be achieved when applying a second laser pulse to the already transferred material, which improves the adhesion resulting in a complete pixel. A new approach of decomposing the transfer material during LIFT transfer was developed. Donor films based on UV absorbing metal complex precursors namely, SnCl2(acac)2 were prepared and transferred using the LIFT technique. Transfer conditions were optimized for the different systems, which were deposited onto sensor-like microstructures. The conductivity of the transferred material at temperatures of about 400 ∘C are in a range usable for SnO2 gas sensors. First sensing tests were carried out and the transferred material proved to change conductivity when exposed to ethanol, acetone, and methane.

Synthesis and photocatalytic properties of different SnO2 microspheres on graphene oxide sheets

International Nuclear Information System (INIS)

Wei, Jia; Xue, Shaolin; Xie, Pei; Zou, Rujia

2016-01-01

Highlights: • Different SnO 2 microspheres were grown on GOs by hydrothermal method. • The morphology was influenced by volume ratio of ethanol and concentrations of precursor. • The shape of SnO 2 microspheres looks like dandelion. • The photocatalytic property is strongly influenced by the SnO 2 morphology on GOs. - Abstract: Different SnO 2 microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO 2 microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV–vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO 2 microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO 2 microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO 2 microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

Assessing the toxicity of Pb- and Sn-based perovskite solar cells in model organism Danio rerio

Science.gov (United States)

Babayigit, Aslihan; Duy Thanh, Dinh; Ethirajan, Anitha; Manca, Jean; Muller, Marc; Boyen, Hans-Gerd; Conings, Bert

2016-01-01

Intensive development of organometal halide perovskite solar cells has lead to a dramatic surge in power conversion efficiency up to 20%. Unfortunately, the most efficient perovskite solar cells all contain lead (Pb), which is an unsettling flaw that leads to severe environmental concerns and is therefore a stumbling block envisioning their large-scale application. Aiming for the retention of favorable electro-optical properties, tin (Sn) has been considered the most likely substitute. Preliminary studies have however shown that Sn-based perovskites are highly unstable and, moreover, Sn is also enlisted as a harmful chemical, with similar concerns regarding environment and health. To bring more clarity into the appropriateness of both metals in perovskite solar cells, we provide a case study with systematic comparison regarding the environmental impact of Pb- and Sn-based perovskites, using zebrafish (Danio Rerio) as model organism. Uncovering an unexpected route of intoxication in the form of acidification, it is shown that Sn based perovskite may not be the ideal Pb surrogate.

Assessing the toxicity of Pb- and Sn-based perovskite solar cells in model organism Danio rerio

Science.gov (United States)

Babayigit, Aslihan; Duy Thanh, Dinh; Ethirajan, Anitha; Manca, Jean; Muller, Marc; Boyen, Hans-Gerd; Conings, Bert

2016-01-01

Intensive development of organometal halide perovskite solar cells has lead to a dramatic surge in power conversion efficiency up to 20%. Unfortunately, the most efficient perovskite solar cells all contain lead (Pb), which is an unsettling flaw that leads to severe environmental concerns and is therefore a stumbling block envisioning their large-scale application. Aiming for the retention of favorable electro-optical properties, tin (Sn) has been considered the most likely substitute. Preliminary studies have however shown that Sn-based perovskites are highly unstable and, moreover, Sn is also enlisted as a harmful chemical, with similar concerns regarding environment and health. To bring more clarity into the appropriateness of both metals in perovskite solar cells, we provide a case study with systematic comparison regarding the environmental impact of Pb- and Sn-based perovskites, using zebrafish (Danio Rerio) as model organism. Uncovering an unexpected route of intoxication in the form of acidification, it is shown that Sn based perovskite may not be the ideal Pb surrogate. PMID:26759068

Paraxial design of an optical element with variable focal length and fixed position of principal planes.

Science.gov (United States)

Mikš, Antonín; Novák, Pavel

2018-05-10

In this article, we analyze the problem of the paraxial design of an active optical element with variable focal length, which maintains the positions of its principal planes fixed during the change of its optical power. Such optical elements are important in the process of design of complex optical systems (e.g., zoom systems), where the fixed position of principal planes during the change of optical power is essential for the design process. The proposed solution is based on the generalized membrane tunable-focus fluidic lens with several membrane surfaces.

SnO2 thin film synthesis for organic vapors sensing at ambient temperature

Directory of Open Access Journals (Sweden)

N.H. Touidjen

2016-12-01

Full Text Available The present work is a study of tin dioxide (SnO2 based thin sensitive layer dedicated to organic vapors detection at ambient temperature. SnO2 thin film was deposited by chemical spray pyrolysis technique. The glass substrate temperature was kept to 400 °C, using a starting solution of 0.1 M tin (II dichloride dihydrate (SnCl2, 2H2O. Films structural and morphological properties were characterized using X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscope (AFM respectively. Films optical characteristics were studied using UV-VIS spectrophotometer. XRD revealed the presence of pure SnO2 polycrystalline thin film with a tetragonal rutile structure. The SEM and AFM observations confirmed the granular morphology with presence of pores in the film surface. The prepared film was tested in various organic vapors (ethanol, methanol and acetone at ambient operating temperature (25 °C ± 2 °C. The obtained results suggested that SnO2 is more sensitive to ethanol vapor with a maximum sensitivity of 35% higher than to methanol and acetone vapors (1% and 3%. The realized SnO2 based sensor demonstrated fast response and recovery times as revealed by the values of 2 s to 3 s towards 47 ppm of ethanol vapor. Keywords: SnO2 thin film, Sensitivity, XRD, SEM, AFM, UV–visible

Enthalpy of mixing of liquid Co–Sn alloys

International Nuclear Information System (INIS)

Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

2014-01-01

Highlights: • The enthalpies of mixing of liquid Co–Sn alloys between T = (673 and 1773) K. • The temperature dependence of the enthalpies of mixing was described. • Full report of measured values including polynomial coefficients. - Abstract: A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process

Ferroelectricity of Sn-doped SrTiO3 perovskites with tin at both A and B sites

Science.gov (United States)

Suzuki, Shoichiro; Honda, Atsushi; Iwaji, Naoki; Higai, Shin'ichi; Ando, Akira; Takagi, Hiroshi; Kasatani, Hirofumi; Deguchi, Kiyoshi

2012-08-01

We successfully obtained Sn-doped SrTiO3 (SSTO) perovskites, and clarified their ferroelectricity and structural properties by using first-principles theoretical calculations. The ferroelectricity of SSTO was confirmed by the appearance of a dielectric permittivity maximum and a clear hysteresis loop of the relationship between the external electric field and the electric flux density below 180 K. X-ray diffraction and Raman spectra revealed the structural phase transition of SSTO at approximately 200 K. We directly observed by spherical aberration corrected scanning transmission electron microscopy with energy-dispersive x-ray spectroscopy that Sn ions are doped into both Sr and Ti sites (SnA and SnB), and that SnA is located at an off-centered position. We also performed theoretical analyses of SSTO and related perovskites, and found that SnA is preferentially located in an off-centered position and that SnA and the O6 octahedron, which includes SnB in its center, oscillate along the antiphase direction in the soft mode. Thus, we propose that the ferroelectricity of SSTO originates from the antiphase off-centering, which induces ferroelectric nanoregions in paraelectric SrTiO3.

Spectroscopic Classifications of Optical Transients with the Lick Shane 3-m telescope

Science.gov (United States)

Dimitriadis, G.; Foley, R. J.

2018-05-01

We report the following classifications of optical transients from spectroscopic observations with the Kast spectrograph on the Shane 3-m telescope. Targets were supplied by ATLAS, ASAS-SN, and the KEGS K2 SN search.

Functional Characterization of TaSnRK2.8 Promoter in Response to Abiotic Stresses by Deletion Analysis in Transgenic Arabidopsis

Directory of Open Access Journals (Sweden)

Hongying Zhang

2017-07-01

Full Text Available Drought, salinity, and cold are the major factors limiting wheat quality and productivity; it is thus highly desirable to characterize the abiotic-stress-inducible promoters suitable for the genetic improvement of plant resistance. The sucrose non-fermenting 1-related protein kinase 2 (SnRK2 family genes show distinct regulatory properties in response to abiotic stresses. The present study characterized the approximately 3000-bp upstream sequence (the 313 bp upstream of the ATG was the transcription start site of the Triticum aestivum TaSnRK2.8 promoter under abscisic acid (ABA and abiotic stresses. Four different-length 5′ deletion fragments of TaSnRK2.8 promoter were fused with the GUS reporter gene and transformed into Arabidopsis. Tissue expression analysis showed that the TaSnRK2.8 promoter region from position -1481 to -821 contained the stalk-specific elements, and the region from position -2631 to -1481 contained the leaf- and root-specific elements. In the ABA-treated seedlings, the deletion analysis showed that the TaSnRK2.8 promoter region from position -821 to -2631 contained ABA response elements. The abiotic stress responses of the TaSnRK2.8 promoter derivatives demonstrated that they harbored abiotic-stress response elements: the region from position -821 to -408 harbored the osmotic-stress response elements, whereas the region from position -2631 to -1481 contained the positive regulatory motifs and the region from position -1481 to -821 contained the leaf- and stalk-specific enhancers. Further deletion analysis of the promoter region from position -821 to -408 indicated that a 125-bp region from position -693 to -568 was required to induce an osmotic-stress response. These results contribute to a better understanding of the molecular mechanisms of TaSnRK2.8 in response to abiotic stresses, and the TaSnRK2.8 promoter seems to be a candidate for regulating the expression of abiotic stress response genes in transgenic plants.

Systematics of Structural, Phase Stability, and Cohesive Properties of η'-Cu6(Sn,In)5 Compounds Occurring in In-Sn/Cu Solder Joints

Science.gov (United States)

Ramos, S. B.; González Lemus, N. V.; Deluque Toro, C. E.; Cabeza, G. F.; Fernández Guillermet, A.

2017-07-01

Motivated by the high solubility of In in ( mC44) η'-Cu6Sn5 compound as well as the occurrence of an In-doped η'-intermetallic in the microstructure of Cu/In-Sn/Cu solder joints, a theoretical study has been carried out to investigate the various physical effects of incorporating In at Sn Wyckoff sites of the binary η'-phase. Systematic ab initio calculations using the projected augmented wave method and Vienna Ab initio Simulation Package were used to determine the composition dependence of the structural and cohesive properties of η'-Cu6(Sn,In)5 compounds, compared with those expected from the binary end-member compounds Cu6Sn5 and Cu6In5. The molar volume shows significant deviations from Vegard's law. The predicted composition dependence of the cohesive properties is discussed using two complementary approaches, viz. a valence-electron density approach as well as a bond-number approach, both accounting for the roughly linear dependence of the cohesive energy on the In content. A microscopic interpretation for this general trend is given in terms of the key contributions to chemical bonding in this class of compounds, namely Cu d-electron overlap and hybridization of Cu d-states with In and Sn p-electron states. Moreover, a crystallographic site approach is developed to accurately establish the phase-stabilizing effect of incorporating In at specific Wyckoff positions of the ( mC44) η'-Cu6Sn5 structure.

Ordered CoSn-type ternary phases in Co3Sn3-xGex

DEFF Research Database (Denmark)

Allred, Jared M.; Jia, Shuang; Bremholm, Martin

2012-01-01

. By taking advantage of the chemical differences between the two crystallographically inequivalent Sn sites in the structure, we observe ordered ternary phases, nominally Co3SnGe2 and Co3Sn2Ge. The electron count and unit cell configuration remain unchanged from CoSn; these observations thus help to clarify...

Sub-spatial resolution position estimation for optical fibre sensing applications

DEFF Research Database (Denmark)

Zibar, Darko; Werzinger, Stefan; Schmauss, Bernhard

2017-01-01

Methods from machine learning community are employed for estimating the position of fibre Bragg gratings in an array. Using the conventional methods for position estimation, based on inverse discrete Fourier transform (IDFT), it is required that two-point spatial resolution is less than gratings...... of reflection coefficients and the positions is performed. From the practical point of view, we can demonstrate the reduction of the interrogator's bandwidth by factor of 2. The technique is demonstrated for incoherent optical frequency domain reflectometry (IOFDR). However, the approach is applicable to any...

Comparative thermodynamic analysis of the Pb-Au0.7Sn0.3 section in the Pb-Au-Sn ternary system

International Nuclear Information System (INIS)

Trumic, B.; Zivkovic, D.; Zivkovic, Z.; Manasijevic, D.

2005-01-01

The results of comparative thermodynamic analysis of Pb-Au 0.7 Sn 0.3 section in Pb-Au-Sn system are presented in this paper. Investigation was done comparatively by calorimetric measurements and thermodynamic calculation according to the general solution model. Thermodynamic parameters, such as partial and integral molar quantities, were determined at different temperatures. The comparison between experimental and calculated results showed mutual agreement. Demixing tendency of lead, presented in the positive deviation from ideal behavior, was confirmed through the study of concentration fluctuation in the long-wavelength limit. Also, chosen alloys in the investigated section were characterized using SEM-EDX analysis

R Aquarii - the large-scale optical nebula and the Mira variable position

International Nuclear Information System (INIS)

Michalitsianos, A.G.; Oliversen, R.J.; Hollis, J.M.; Kafatos, M.; Crull, H.E.

1988-01-01

The R Aquarii symbiotic star system is surrounded by a large-scale optical nebula. Observations of the nebular forbidden O III structure are presented and its morphological significance are discussed in context with previously observed small-scale radio-continuum features, which may be related. It is suggested that a precessing accretion disk may explain the global features of both the large-scale optical emission and the small-scale radio emission. Moreover, an accurate position has been determined of the system's Mira, which suggests that a recent theoretical model, yielding an egg-shaped central H II region for symbiotic systems with certain physical parameters, may apply to R Aquarii. The optical position of the 387 d period Mira variable is consistent with previous findings in the radio, that SiO maser emission is far removed from the Mira photosphere. 25 references

Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system

International Nuclear Information System (INIS)

Chang Zeng-Guang; Zhang Jing-Tao; Niu Yue-Ping; Gong Shang-Qing

2012-01-01

We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type

Correlation between the resistivity and the atomic clusters in liquid Cu-Sn alloys

Science.gov (United States)

Jia, Peng; Zhang, Jinyang; Hu, Xun; Li, Cancan; Zhao, Degang; Teng, XinYing; Yang, Cheng

2018-05-01

The liquid structure of CuxSn100-x (x = 0, 10, 20, 33, 40, 50, 60, 75, 80 and 100) alloys with atom percentage were investigated with resistivity and viscosity methods. It can be found from the resistivity data that the liquid Cu75Sn25 and Cu80Sn20 alloys had a negative temperature coefficient of resistivity (TCR), and liquid Cu75Sn25 alloy had a minimum value of -9.24 μΩ cm K-1. While the rest of liquid Cu-Sn alloys had a positive TCR. The results indicated that the Cu75Sn25 atomic clusters existed in Cu-Sn alloys. In addition, the method of calculating the percentage of Cu75Sn25 atomic clusters was established on the basis of resistivity theory and the law of conservation of mass. The Cu75Sn25 alloy had a maximum volume of the atomic clusters and a highest activation energy. The results further proved the existence of Cu75Sn25 atomic clusters. Furthermore, the correlation between the liquid structure and the resistivity was established. These results provide a useful reference for the investigation of liquid structure via the sensitive physical properties to the liquid structure.

Growth of highly textured SnS on mica using an SnSe buffer layer

International Nuclear Information System (INIS)

Wang, S.F.; Fong, W.K.; Wang, W.; Surya, C.

2014-01-01

We report the growth of SnS thin films on mica substrates by molecular beam epitaxy. Excellent 2D layered structure and strong (001) texture were observed with a record low rocking curve full width at half maximum of ∼ 0.101° for the SnS(004) diffraction. An interface model is used to investigate the nucleation of SnS on mica which indicates the co-existence of six pairs of lateral growth orientations and is in excellent agreement with the experimental Φ-scan measurements indicating 12 peaks separated by 30° from each other. To control the lateral growth of the SnS epilayers we investigate the utilization of a thin SnSe buffer layer deposited on the mica substrate prior to the growth of the SnS thin film. The excellent lattice match between SnSe and mica enhances the alignment of the nucleation of SnS and suppresses the minor lateral orientations along the mica[110] direction and its orthogonal axis. Detailed low-frequency noise measurement was performed to characterize the trap density in the films and our results clearly demonstrate substantial reduction in the density of the localized states in the SnS epilayer with the use of an SnSe buffer layer. - Highlights: • A record low rocking curve FWHM for deposited SnS on mica • Investigation of the nucleation of SnS on mica using the interface model • Investigation of nucleation mechanism by phi-scan measurement • Grain boundary formation from crystallites of various nucleation orientations • Suppression of nucleation orientations using an SnSe buffer layer

SN1987A's Twentieth Anniversary

Science.gov (United States)

2007-02-01

Light Curve of SN1987A/small> Astronomers John Danziger and Patrice Bouchet, who were there at the time, recall: "When astronomers at La Silla arrived for the ritual afternoon tea at 4pm on the 24th February 1987 after the previous night's clear observing, they were greeted by the news that a supernova had been detected in the LMC the previous night. The tea-time ritual of groggy astronomers quietly sipping their tea was transformed, to be succeeded by flurries of excited but still to some extent uncoordinated planning. Nobody doubted for one second that the sky would be clear and there would be excitement galore in the days and nights ahead. And indeed there was! A large observatory such as La Silla with its many telescopes can be considered like a naval fleet consisting of many ships from torpedo boats to cruisers and even aircraft carriers. La Silla had them all. All observers were encouraged to plan for observing SN1987A by whatever means at their disposal." "Ironically, the supernova was too bright for the state-of-the-art 4m-class telescopes and some of them had to be stopped down, e.g. by half-closed telescope covers," says Jason Spyromilio (ESO). Some of the smaller telescopes took their chance. The 61-cm Bochum telescope on La Silla was used, on a nearly daily basis for more than a year, to measure optical spectroscopy with photometric accuracy. Since the LMC is circumpolar for most southern observatories, this also meant that there exists an uninterrupted record of the photometry and spectroscopy; else part of the peak phase, which lasted into May of 1987, would have been missed. By July, the first conference on SN 1987A, organised by John Danziger, had already taken place at ESO in Garching to be followed by several others during that year and following years. The optical light curve of SN 1987A was rather different from those of previously observed core-collapse supernovae. The old models of spherical explosions had to be revised. The spectroscopic evolution

The formation of α-phase SnS nanorods by PVP assisted polyol synthesis: Phase stability, micro structure, thermal stability and defects induced energy band transitions

Energy Technology Data Exchange (ETDEWEB)

Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com

2017-05-01

We report the formation of single phase of SnS nanostructure through PVP assisted polyol synthesis by varying the source concentration ratio (Sn:S) from 1:1M to 1:12M. The effect of PVP concentration and reaction medium towards the preparation of SnS nanostructure is systematically studied through confocal Raman spectrometer, X-ray diffraction, thermogravimetry analysis, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis–NIR absorption and fluorescence spectrophotometers. The surface morphology of SnS nanostructure changes from nanorods to spherical shape with increasing PVP concentration from 0.15M to 0.5M. Raman analysis corroborates that Raman active modes of different phases of Sn-S are highly active when Raman excitation energy is slightly greater than the energy band gap of the material. The presence of intrinsic defects and large number of grain boundaries resulted in an improved thermal stability of 20 °C during the phase transition of α-SnS. Band gap calculation from tauc plot showed the direct band gap of 1.5 eV which is attributed to the single phase of SnS, could directly meet the requirement of an absorber layer in thin film solar cells. Finally, we proposed an energy band diagram for as synthesized single phase SnS nanostructure based on the experimental results obtained from optical studies showing the energy transitions attributed to band edge transition and also due to the presence of intrinsic defects. - Highlights: • PVP stabilizes the orthorhombic (α) phase of SnS. • Optical band gap of P type SnS tuned by PVP for photovoltaic applications. • The formation of Sn rich SnS phase is investigated through XPS analysis. • Intrinsic defects enhance the thermal stability of α-SnS. • The feasibility of energy transition liable to point defects is discussed.

Interactions of Cu-substrates with titanium-alloyed Sn-Zn solders

Directory of Open Access Journals (Sweden)

Soares D.

2006-01-01

Full Text Available The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the second series,. The contact times were up to 3600 s. The contact zones have been characterized by optical and scanning electron microscope. Two layers have been found along the interfaces solid/liquid. The first and the second layers are identical, respectively, with γ and ε phases of the Cu-Zn system. No changes of the chemical compositions were detected for the tested temperatures and reaction times. Continuous parabolic growth of the total diffusion zone thickness with the time of diffusion is observed. The growth is due mainly to one the formed layers (γ while the thickness of the ε-phase layer, stays almost constant for all tested diffusion times and temperatures.

Effect of Annealing Temperature on Structural, Optical, and Electrical Properties of Sol-Gel Spin-Coating-Derived Cu2ZnSnS4 Thin Films

Science.gov (United States)

Hosseinpour, Rabie; Izadifard, Morteza; Ghazi, Mohammad Ebrahim; Bahramian, Bahram

2018-02-01

The effect of annealing temperature on structural, optical, and electrical properties of Cu2ZnSnS4 (CZTS) thin films grown on a glass substrate by spin coating sol-gel technique has been studied. Structural study showed that all samples had kesterite crystalline structure. Scanning electron microscopy images showed that the crystalline quality of the samples was improved by heat treatment. Optical study showed that the energy gap values for the samples ranged from 1.55 eV to 1.78 eV. Moreover, good optical conductivity values (1012 S-1 to 1014 S-1) were obtained for the samples. Investigation of the electrical properties of the CZTS thin films showed that the carrier concentration increased significantly with the annealing temperature. The photoelectrical behavior of the samples revealed that the photocurrent under light illumination increased significantly. Overall, the results show that the CZTS thin films annealed at 500°C had better structural, optical, and electrical properties and that such CZTS thin films are desirable for use as absorber layers in solar cells. The photovoltaic properties of the CZTS layer annealed at 500°C were also investigated and the associated figure of merit calculated. The results showed that the fabricated ZnS-CZTS heterojunction exhibited good rectifying behavior but rather low fill factor.

Objective-lens-free Fiber-based Position Detection with Nanometer Resolution in a Fiber Optical Trapping System.

Science.gov (United States)

Ti, Chaoyang; Ho-Thanh, Minh-Tri; Wen, Qi; Liu, Yuxiang

2017-10-13

Position detection with high accuracy is crucial for force calibration of optical trapping systems. Most existing position detection methods require high-numerical-aperture objective lenses, which are bulky, expensive, and difficult to miniaturize. Here, we report an affordable objective-lens-free, fiber-based position detection scheme with 2 nm spatial resolution and 150 MHz bandwidth. This fiber based detection mechanism enables simultaneous trapping and force measurements in a compact fiber optical tweezers system. In addition, we achieved more reliable signal acquisition with less distortion compared with objective based position detection methods, thanks to the light guiding in optical fibers and small distance between the fiber tips and trapped particle. As a demonstration of the fiber based detection, we used the fiber optical tweezers to apply a force on a cell membrane and simultaneously measure the cellular response.

The value of imaging in standing position in preoperative breast lymphoscintigraphy.

Science.gov (United States)

Anagnostou, Christos; Baiocco, Cinzia; Arnulfo, Alberto; Liberatore, Mauro; Baccheschi, Anna Maria; Inglese, Eugenio

2011-08-01

Breast lymphoscintigraphy is an accurate technique, but in a minority of cases the sentinel node (SN) visualization cannot be achieved or can be very difficult. We evaluated the potential clinical advantages and limitations of performing imaging in the standing position. The aim was to establish if this examination modality is quicker and helpful in the presence of "hidden" SN, checking also for any influence of SN skin landmarking in the upright position on the correct intraoperative SN identification. The overall objective was to verify if the standing position can be routinely used in breast lymphoscintigraphy. A total of 144 patients underwent lymphoscintigraphy in both standing and supine positions. In both modalities, a skin landmark was set coincident with the SN orthogonal projections. The acquisition times of 2 groups (each consisting of 45 patients) examined with the standing or supine acquisition modality, were compared. In 6 cases with hidden SN and in 34 cases with difficult or partial visualization in one of the supine views, the standing protocol was effective and led to better and quicker visualization of lymph nodes (median examination time: 25.5 minutes standing, 35.5 minutes supine). Significant differences in skin landmark position between the 2 modalities were present only in overweight patients and in large breasts. This, however, did not have a negative impact on successful intraoperative localization of SN with the gamma probe. Standing acquisition resulted to be a faster, easier, and more accurate examination protocol and can be used as the routine method for SN detection in breast lymphoscintigraphy.

Comparative study on optical performance and visual outcomes between two diffractive multifocal lenses: AMO Tecnis ® ZMB00 and AcrySof ® IQ ReSTOR ® Multifocal IOL SN6AD1

Directory of Open Access Journals (Sweden)

Mario Augusto Pereira Dias Chaves

2016-06-01

Full Text Available ABSTRACT Purpose: To compare the optical performance and visual outcomes between two diffractive multifocal lenses: AMO Tecnis® ZMB00 and AcrySof® ReSTOR® SN6AD1. Methods: This prospective, non-randomized comparative study included the assessment of 74 eyes in 37 patients referred for cataract surgery and candidates for multifocal intraocular lens implants. Exclusion criteria included existence of any other eye disease, previous eye surgery, high axial myopia, preoperative corneal astigmatism of >1.00 cylindrical diopter (D, and intraoperative or postoperative complications. Ophthalmological evaluation included the measurement of uncorrected distance visual acuity (UDVA, corrected distance visual acuity (CDVA, distance-corrected near visual acuity (DCNVA, and distance-corrected intermediate visual acuity (DCIVA, with analysis of contrast sensitivity (CS, wavefront, and visual defocus curve. Results: Postoperative UDVA was 0.09 and 0.08 logMAR in the SN6AD1 and ZMB00 groups, respectively (p=0.868; postoperative CDVA was 0.04 and 0.02 logMAR in the SN6AD1 and ZMB00 groups, respectively (p=0.68; DCIVA was 0.17 and 0.54 logMAR in the SN6AD1 and ZMB00 groups, respectively (p=0.000; and DCNVA was 0.04 and 0.09 logMAR in the SN6AD1 and ZMB00 groups, respectively (p=0.001. In both cases, there was an improvement in the spherical equivalent and UDVA (p<0.05. Under photopic conditions, the SN6AD1 group had better CS at low frequencies without glare (p=0.04; however, the ZMB00 group achieved better sensitivity at high frequencies with glare (p=0.003. The SN6AD1 and ZMB00 lenses exhibited similar behavior for intermediate vision, according to the defocus curve; however, the ZMB00 group showed a shorter reading distance than the SN6AD1 group. There were no significant differences regarding aberrometry between the two groups. Conclusion: Both lenses promoted better quality of vision for both long and short distances and exhibited a similar behavior for

SN 2016X: a type II-P supernova with a signature of shock breakout from explosion of a massive red supergiant

Science.gov (United States)

Huang, F.; Wang, X.-F.; Hosseinzadeh, G.; Brown, P. J.; Mo, J.; Zhang, J.-J.; Zhang, K.-C.; Zhang, T.-M.; Howell, D.-A.; Arcavi, I.; McCully, C.; Valenti, S.; Rui, L.-M.; Song, H.; Xiang, D.-F.; Li, W.-X.; Lin, H.; Wang, L.-F.

2018-04-01

We present extensive ultraviolet (UV) and optical photometry, as well as dense optical spectroscopy, for type II Plateau (IIP) supernova SN 2016X that exploded in the nearby (˜15 Mpc) spiral galaxy UGC 08041. The observations span the period from 2 to 180 d after the explosion; in particular, the Swift UV data probably captured the signature of shock breakout associated with the explosion of SN 2016X. It shows very strong UV emission during the first week after explosion, with a contribution of ˜20-30 per cent to the bolometric luminosity (versus ≲15 per cent for normal SNe IIP). Moreover, we found that this supernova has an unusually long rise time of about 12.6 ± 0.5 d in the R band (versus ˜7.0 d for typical SNe IIP). The optical light curves and spectral evolution are quite similar to the fast-declining type IIP object SN 2013ej, except that SN 2016X has a relatively brighter tail. Based on the evolution of photospheric temperature as inferred from the Swift data in the early phase, we derive that the progenitor of SN 2016X has a radius of about 930 ± 70 R⊙. This large-size star is expected to be a red supergiant star with an initial mass of ≳19-20 M⊙ based on the mass-radius relation of the Galactic red supergiants, and it represents one of the most largest and massive progenitors found for SNe IIP.

Sensors of the gas CO in thin film of SnO2:Cu

International Nuclear Information System (INIS)

Tirado G, S.; Sanchez Z, F. E.

2011-10-01

Thin films of SnO 2 :Cu with different thickness, were deposited on soda-lime glass substrates and prepared by the Sol-gel process and repeated immersion. The sensor properties of these films to the gas CO for the range of 0-200 ppm in the gas concentration and operating to temperatures of 23, 100, 200, and 300 C were studied. Prepared films of pure SnO 2 were modified superficially with 1, 3, 5 and 10 layers of the catalyst Cu (SnO 2 :Cu) with the purpose of studying the effect on the sensor capacity of the gas CO by part of the films SnO 2 :Cu. Using the changes in the electric properties of the films with the incorporation of the different copper layers and experimental conditions, the sensor modifications of the gas CO were evaluated. To complete this study, was realized a characterization of the superficial morphology of the films by scanning electron microscopy and atomic force microscopy, equally was studied their structure and their electric and optical properties. (Author)

Medicina-Noto VLBI observation of SN2013ej

Science.gov (United States)

Sokolovsky, K.; Giroletti, M.; Stagni, M.; Nanni, M.; Mahabal, A.

2013-08-01

We used the 32m radio telescopes of Istituto di Radioastronomia (INAF-IRA) in Medicina and Noto as a two-element very long baseline interferometer to search for a possible radio counterpart of SN2013ej, a type IIP supernova (CBET #3606, ATel #5228, #5229, #5230, #5237, #5243) in M74. The observations were conducted at 6.7 GHz on 2013 July 31.3 UT, 6 days after the first optical detection reported in CBET #3609.

Optical position meters analyzed in the noninertial reference frames

International Nuclear Information System (INIS)

Tarabrin, Sergey P.; Seleznyov, Alexander A.

2008-01-01

In the framework of general relativity we develop a method for the analysis of the operation of the optical position meters in their photodetectors proper reference frames. These frames are noninertial in general due to the action of external fluctuative forces on meters test masses, including detectors. For comparison we also perform the calculations in the laboratory (globally inertial) reference frame and demonstrate that for certain optical schemes laboratory-based analysis results in unmeasurable quantities, in contrast to the detector-based analysis. We also calculate the response of the simplest optical meters to weak plane gravitational waves and fluctuative motions of their test masses. It is demonstrated that for the round-trip meter analysis in both the transverse-traceless (TT) and local Lorentz (LL) gauges produces equal results, while for the forward-trip meter corresponding results differ in accordance with different physical assumptions (e.g. procedure of clocks synchronization) implicitly underlying the construction of the TT and LL gauges.

Synthesis and photocatalytic properties of different SnO2 microspheres on graphene oxide sheets

Science.gov (United States)

Wei, Jia; Xue, Shaolin; Xie, Pei; Zou, Rujia

2016-07-01

Different SnO2 microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO2 microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV-vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO2 microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO2 microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO2 microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

SN 2012au: A GOLDEN LINK BETWEEN SUPERLUMINOUS SUPERNOVAE AND THEIR LOWER-LUMINOSITY COUNTERPARTS

International Nuclear Information System (INIS)

Milisavljevic, Dan; Soderberg, Alicia M.; Margutti, Raffaella; Drout, Maria R.; Marion, G. Howie; Sanders, Nathan E.; Lunnan, Ragnhild; Chornock, Ryan; Berger, Edo; Foley, Ryan J.; Challis, Pete; Kirshner, Robert P.; Dittmann, Jason; Bieryla, Allyson; Kamble, Atish; Chakraborti, Sayan; Hsiao, Eric Y.; Fesen, Robert A.; Parrent, Jerod T.; Levesque, Emily M.

2013-01-01

We present optical and near-infrared observations of SN 2012au, a slow-evolving supernova (SN) with properties that suggest a link between subsets of energetic and H-poor SNe and superluminous SNe. SN 2012au exhibited conspicuous Type-Ib-like He I lines and other absorption features at velocities reaching ≈2 × 10 4 km s –1 in its early spectra, and a broad light curve that peaked at M B = –18.1 mag. Models of these data indicate a large explosion kinetic energy of ∼10 52 erg and 56 Ni mass ejection of M Ni ≈ 0.3 M ☉ on par with SN 1998bw. SN 2012au's spectra almost one year after explosion show a blend of persistent Fe II P-Cyg absorptions and nebular emissions originating from two distinct velocity regions. These late-time emissions include strong [Fe II], [Ca II], [O I], Mg I], and Na I lines at velocities ∼> 4500 km s –1 , as well as O I and Mg I lines at noticeably smaller velocities ∼ –1 . Many of the late-time properties of SN 2012au are similar to the slow-evolving hypernovae SN 1997dq and SN 1997ef, and the superluminous SN 2007bi. Our observations suggest that a single explosion mechanism may unify all of these events that span –21 ∼ B ∼< –17 mag. The aspherical and possibly jetted explosion was most likely initiated by the core collapse of a massive progenitor star and created substantial high-density, low-velocity Ni-rich material.

Thermoelectric prospects of chemically deposited PbSe and SnSe thin films

Science.gov (United States)

Nair, P. K.; Martínez, Ana Karen; Rosa García Angelmo, Ana; Barrios Salgado, Enue; Nair, M. T. S.

2018-03-01

Thin films of PbSe of 400-600 nm in thickness, were obtained via chemical deposition from a solution containing lead nitrate, thiourea and selenosufate. SnSe thin films of 90-180 nm in thickness, were also obtained by chemical deposition from a solution containing selenosulfate. Optical and electrical properties of these thin films were significantly altered by heating them in selenium vapor at 300 °C. Thin film PbSe has a bandgap (Eg) of 1.17 eV (direct gap, forbidden transitions), which decreases to 0.77 eV when it has been heated. Its electrical conductivity (σ) is p-type: 0.18 Ω-1 cm-1 (as-prepared), and 6.4 Ω-1 cm-1 when heated. Thin film SnSe is of orthorhombic crystalline structure which remains stable when heated at 300 °C, but its Eg increases from 1.12 eV (indirect) in as-prepared film to 1.5 eV (direct, forbidden transitions) upon heating. Its electrical conductivity is p-type, which increases from 0.3 Ω-1 cm-1 (as-prepared) to 1 Ω-1 cm-1 when heated (without Se-vapor). When SnSe film is heated at 300 °C in the presence of Se-vapor, they transform to SnSe2, with Eg of 1.5 eV (direct, forbidden) with n-type electrical conductivity, 11 Ω-1 cm-1. The Seebeck coefficient for the PbSe films is: +0.55 mV K-1 (as prepared) and +0.275 mV K-1 (heated); for SnSe films it is: +0.3 mV K-1 (as prepared) and +0.20 mV K-1 (heated); and for SnSe2 film, - 0.35 mV K-1. A five-element PbSe-SnSe2-PbSe-SnSe2-PbSe thermoelectric device demonstrated 50 mV for a temperature difference ΔT = 20 °C (2.5 mV K-1). For SnSe-SnSe2-SnSe-SnSe2-SnSe device, the value is 15 mV for ΔT = 20 °C (0.75 mV K-1). Prospect of these thin films in thermoelectric devices of hybrid materials, in which the coatings may be applied on distinct substrate and geometries is attractive.

Metabolism of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine in the human neutrophil

International Nuclear Information System (INIS)

Triggiani, M.; D'Souza, D.M.; Chilton, F.H.

1991-01-01

The biosynthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-2-acetyl-GPC) together with that of 1-alkyl-2-acetyl-GPC (platelet-activating factor) has been demonstrated in a variety of inflammatory cells and tissues. It has been hypothesized that the relative proportion of these phospholipids produced upon cell activation may be influenced by their rates of catabolism. We studied the catabolism of 1-acyl-2-acetyl-GPC in resting and activated human neutrophils and compared it to that of 1-alkyl-2-acetyl-GPC. Neutrophils rapidly catabolize both 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC; however, the rate of catabolism of 1-acyl-2-acetyl-GPC is approximately 2-fold higher than that of 1-alkyl-2-acetyl-GPC. In addition, most of 1-acyl-2-acetyl-GPC is catabolized through a pathway different from that of 1-alkyl-2-acetyl-GPC. The main step in the catabolism of 1-acyl-2-acetyl-GPC is the removal of the long chain at the sn-1 position; the long chain residue is subsequently incorporated either into triglycerides or into phosphatidylcholine. The 1-lyso-2-acetyl-GPC formed in this reaction is then further degraded to glycerophosphocholine, choline, or phosphocholine. 1-Acyl-2-acetyl-GPC is also catabolized, to a lesser extent, through deacetylation at the sn-2 position and reacylation with a long chain fatty acid. Stimulation of neutrophils by A23187 results in a higher rate of catabolism of 1-acyl-2-acetyl-GPC by increasing both the removal of the long chain at the sn-1 position and the deacetylation-reacylation at the sn-2 position. In a broken cell preparation, the cytosolic fraction of the neutrophil was shown to contain an enzyme activity which cleaved the sn-1 position of 1-acyl-2-acetyl-GPC and 1-acyl-2-lyso-GPC but not of 1,2-diacyl-GPC

Structural, Optical and Ethanol Sensing Properties of Dy-Doped SnO2 Nanoparticles

Science.gov (United States)

Shaikh, F. I.; Chikhale, L. P.; Nadargi, D. Y.; Mulla, I. S.; Suryavanshi, S. S.

2018-04-01

We report a facile co-precipitation synthesis of dysprosium (Dy3+) doped tin oxide (SnO2) thick films and their use as gas sensors. The doping percentage (Dy3+) was varied from 1 mol.% to 4 mol.% with the step of 1 mol.%. As-produced material with varying doping levels were sintered in air; and by using a screen printing technique, their thick films were developed. Prior to sensing performance investigations, the films were examined for structural, morphological and compositional properties using x-ray diffraction, a field emission scanning electron microscope, a transmission electron microscope, selected area electron diffraction, energy dispersive analysis by x-rays, Fourier transform infrared spectroscopy and Raman spectroscopic techniques. The structural analyses revealed formation of single phase nanocrystalline material with tetragonal rutile structure of SnO2. The morphological analyses confirmed the nanocrystalline porous morphology of as-developed material. Elemental analysis defined the composition of material in accordance with the doping concentration. The produced sensor material exhibited good response towards different reducing gases (acetone, ethanol, LPG, and ammonia) at different operating temperatures. The present study confirms that the Dy3+ doping in SnO2 enhances the response towards ethanol with reduction in operating temperature. Particularly, 3 mol.% Dy3+ doped sensor exhibited the highest response (˜ 92%) at an operating temperature of 300°C with better selectivity, fast response (˜ 13 s) and recovery (˜ 22 s) towards ethanol.

Systematic study of Si-based GeSn photodiodes with 2.6 µm detector cutoff for short-wave infrared detection.

Science.gov (United States)

Pham, Thach; Du, Wei; Tran, Huong; Margetis, Joe; Tolle, John; Sun, Greg; Soref, Richard A; Naseem, Hameed A; Li, Baohua; Yu, Shui-Qing

2016-03-07

Normal-incidence Ge 1-x Sn x photodiode detectors with Sn compositions of 7 and 10% have been demonstrated. Such detectors were based on Ge/Ge 1-x Sn x /Ge double heterostructures grown directly on a Si substrate via a chemical vapor deposition system. A temperature-dependence study of these detectors was conducted using both electrical and optical characterizations from 300 to 77 K. Spectral response up to 2.6 µm was achieved for a 10% Sn device at room temperature. The peak responsivity and specific detectivity (D*) were measured to be 0.3 A/W and 4 × 10 9 cmHz 1/2 W -1 at 1.55 µm, respectively. The spectral D* of a 7% Sn device at 77 K was only one order-of-magnitude lower than that of an extended-InGaAs photodiode operating in the same wavelength range, indicating the promising future of GeSn-based photodetectors.

Deep-lying hole states in the optical model

International Nuclear Information System (INIS)

Klevansky, S.P.; Lemmer, R.H.

1982-01-01

The strength function for deep-lying hole states in an optical potential is studied by the method of Green's functions. The role of isospin is emphasized. It is shown that, while the main trends of the experimental data on hole states in isotopes of Sn and Pd can be described by an energy independent optical potential, intermediate structures in these data indicate the specific nuclear polarization effects have to be included. This is done by introducing doorway states of good isospin into the optical model potential. Such states consist of neutron hole plus proton core vibrations as well as more complicated excitations that are analog states of proton hole plus neutron core vibrations of the parent nuclear system. Specific calculations for 115 Sn and 103 Pd give satisfactory fits to the strength function data using optical model and doorway state parameters that are reasonable on physical grounds

Photoelectrochemical properties of orthorhombic and metastable phase SnS nanocrystals synthesized by a facile colloidal method

Energy Technology Data Exchange (ETDEWEB)

Huang, Po-Chia [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Huang, Jow-Lay [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan, ROC (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China); Wang, Sheng-Chang; Shaikh, Muhammad Omar [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan, ROC (China); Lin, Chia-Yu [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

2015-12-01

SnS of orthorhombic (OR) and metastable (SnS) phases were synthesized by using a simple and facile colloidal method. The tin precursor was synthesized using tin oxide (SnO) and oleic acid (OA), while the sulfur precursor was prepared using sulfur powder (S) and oleyamine (OLA). The sulfur precursor was injected into the tin precursor and the prepared SnS nanocrystals were precipitated at a final reaction temperature of 180 °C. The results show that hexamethyldisilazane (HMDS) can be successfully used as a surfactant to synthesize monodisperse 20 nm metastable SnS nanoparticles, while OR phase SnS nanosheets were obtained without HMDS. The direct bandgap observed for the metastable SnS phase is higher (1.66 eV) as compared to the OR phase (1.46 eV). The large blueshift in the direct bandgap of metastable SnS is caused by the difference in crystal structure. The blueshift in the direct band gap value for OR-SnS could be explained by quantum confinement in two dimensions in the very thin nanosheets. SnS thin films used as a photo anode in a photoelectrochemical (PEC) cell were prepared by spin coating on the fluorine-doped tin oxide (FTO) substrates. The photocurrent density of the SnS (metastable SnS)/FTO and SnS (OR)/FTO are 191.8 μA/cm{sup 2} and 57.61 μA/cm{sup 2} at an applied voltage of − 1 V at 150 W, respectively. These narrow band gap and low cost nanocrystals can be used for applications in future optoelectronic devices. - Highlights: • A facile method to synthesize two different phases of SnS having different morphological and optical properties. • The phases and morphologies of SnS nanocrystal can be controlled by adding capping surfactant hexamethyldisilazane (HMDS). • As we know, this is the first metastable SnS photoanode for application in a photoelectrochemical cell.

Metal chloride precursor synthesization of Cu{sub 2}ZnSnS{sub 4} solar cell materials

Energy Technology Data Exchange (ETDEWEB)

Yeh, Min-Yen; Huang, Yu-Fong; Huang, Cheng-Liang; Yang, Chyi-Da [National Kaohsiung Marine University, Kaohsiung, Taiwan (China); Wuu, Dong-Sing [National Chung Hsing University, Taichung, Taiwan (China); Lei, Po-Hsun [National Formosa University, Yunlin, Taiwan (China)

2014-07-15

Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films with kesterite structures were prepared by directly sol-gel synthesizing spin-coated precursors on soda-lime-glass (SLG) substrates. The CZTS precursors were prepared by using solutions of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea. The ratio of SnCl{sub 4} in the precursors was found to play a critical role in the synthesization of CZTS. CZTS phases of SnS and SnS{sub 2} were observed in the synthesized films as prepared using precursors with a close to stoichiometric ratio of CuCl{sub 2}:ZnCl{sub 2}:SnCl{sub 4}:CH{sub 4}N{sub 2}S = 4:1:1:8, where SnCl{sub 4} was 1 mol/l. The amounts of the educed SnS and SnS{sub 2} phases observed in the SEM images could be readily reduced by decreasing the volume of SnCl{sub 4} in the mixed solution. With decreasing amount of SnCl{sub 4} from 1 mol/l, the as prepared CZTS reveals a significant improvement in its crystalline properties. In this work, CZTS with an average absorption coefficient and an optical energy gap of over 10{sup 4} cm{sup -1} and ∼1.5 eV, respectively, was obtained using precursors of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea mixed in a ratio of 2:1:0.25:8, and it had good crystallinity revealing a Cu-poor composition.