MIS photodetectors on intrinsic semiconductors for thermal infrared imagery - A design aid for focal plane matrices

Science.gov (United States)

Farre, J.

1980-12-01

The physical mechanisms determining the operational behavior of an MIS photodetector for thermal infrared imagery based on a two-dimensional matrix of intrinsic semiconductors constituting a charge injection device are examined. The general principles of a thermal infrared imagery system composed of radiation source, atmosphere, sensor system with entrance optics, detector and environment, and data processing means are introduced, and the parameters of the system as a whole influencing detector characteristics are indicated. The properties of an ideal and a real MIS photodetector are discussed, with attention given to the physical properties of narrow bandgap materials such as InSb, operational properties in the dynamic regime, the carrier tunneling component and experimentally observed instability phenomena. The matrix organization of MIS photodetectors is then considered, with particular attention given to a simple model of charge transfer between two electrodes and the two principal reading mechanisms: charge injection and the floating potential method.

Optoelectronic Characterization of Infrared Photodetector Fabricated on Ge-on-Si Substrate.

Science.gov (United States)

Khurelbaatar, Zagarzusem; Kil, Yeon-Ho; Kim, Taek Sung; Shim, Kyu-Hwan; Hong, Hyobong; Choi, Chel-Jong

2015-10-01

We report on the optoelectronic characterization of Ge p-i-n infrared photodetector fabricated on Ge-on-Si substrate using rapid thermal chemical vapor deposition (RTCVD). The phosphorous doping concentration and the root mean square (RMS) surface roughness of epitaxial layer was estimated to be 2 x 10(18) cm(-3) and 1.2 nm, respectively. The photodetector were characterized with respect to their dark, photocurrent and responsivities in the wavelength range of 1530-1630 nm. At 1550 nm wavelength, responsivity of 0.32 A/W was measured for a reverse bias of 1 V, corresponding to 25% external quantum efficiency, without an optimal antireflection coating. Responsivity drastically reduced from 1560 nm wavelength which could be attributed to decreased absorption of Ge at room temperature.

High-Performance Ultraviolet-to-Infrared Broadband Perovskite Photodetectors Achieved via Inter-/Intraband Transitions

KAUST Repository

Alwadai, Norah Mohammed Mosfer

2017-10-17

A high-performance vertically injected broadband UV-to-IR photodetector based on Gd-doped ZnO nanorods (NRs)/CH3NH3PbI3 perovskite heterojunction was fabricated on metal substrates. Our perovskite-based photodetector is sensitive to a broad spectral range, from ultraviolet to infrared light region (λ = 250–1357 nm). Such structure leads to a high photoresponsivity of 28 and 0.22 A/W, for white light and IR illumination, respectively, with high detectivity values of 1.1 × 1012 and 9.3 × 109 Jones. Optical characterizations demonstrate that the IR detection is due to intraband transition in the perovskite material. Metal substrate boosts carrier injection, resulting in higher responsivity compared to the conventional devices grown on glass, whereas the presence of Gd increases the ZnO NRs performance. For the first time, the perovskite-based photodetector is demonstrated to extend its detection capability to IR (>1000 nm) with high room temperature responsivity across the detected spectrum, leading to a high-performance ingenious cost-effective UV-to-IR broadband photodetector design for large-scale applications.

Nano-structured Cu(In,Al)Se{sub 2} near-infrared photodetectors

Energy Technology Data Exchange (ETDEWEB)

Chang, Ruo-Ping [Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Perng, Dung-Ching, E-mail: dcperng@ee.ncku.edu.tw [Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China)

2013-02-01

We have demonstrated nano-structured Cu(In,Al)Se{sub 2} (CIAS) near-infrared (NIR) photodetectors (PDs). The CIAS NIR PDs were fabricated on ZnO nanowires (NWs)/ZnO/Mo/ITO (indium tin oxide) glass substrate. CIAS film acted as a sensing layer and sparse ZnSe NWs, which were converted from ZnO NWs after selenization process, were embedded in the CIAS film to improve the amplification performance of the NIR PDs. X-ray diffraction patterns show that the CIAS film is a single phased polycrystalline film. Scanning electron microscopy was used to examine the morphology of the CIAS film and the growth of NWs. Two detection schemes, plain Al–CIAS–Al metal–semiconductor–metal structure and vertical structure with CIAS/ZnSe NWs annular p–n junctions, were studied. The nano-structured NIR PDs demonstrate two orders of magnitude for the annular p–n junction and one order of magnitude for the MSM structure in photocurrent amplification. The responsivities of the PDs using both sensing structures have the same cut-off frequency near 790 nm. - Highlights: ► We demonstrate nano-structured Cu(In,Al)Se{sub 2} near-infrared photodetectors. ► Photodetectors were fabricated on ZnO nanowires/ZnO/Mo/ITO glass substrate. ► Two detection schemes studied: a plain MSM structure and a vertical structure. ► Photocurrent amplification for the vertical structure is two orders of magnitude. ► Photocurrent amplification for the MSM structure is one order of magnitude.

Quantum Well Infrared Photodetectors Physics and Applications

CERN Document Server

Schneider, Harald

2007-01-01

Addressed to both students as a learning text and scientists/engineers as a reference, this book discusses the physics and applications of quantum-well infrared photodetectors (QWIPs). It is assumed that the reader has a basic background in quantum mechanics, solid-state physics, and semiconductor devices. To make this book as widely accessible as possible, the treatment and presentation of the materials is simple and straightforward. The topics for the book were chosen by the following criteria: they must be well-established and understood; and they should have been, or potentially will be, used in practical applications. The monograph discusses most aspects relevant for the field but omits, at the same time, detailed discussions of specialized topics such as the valence-band quantum wells.

Quantum dot infrared photodetectors based on indium phosphide

International Nuclear Information System (INIS)

Gebhard, T.

2011-01-01

The subject of this work is a systematic study of quantum dot infrared photodetectors based on indium-phosphide substrate by means of various spectroscopic and electronic measurement methods in order to understand the physical and technological processes. This enables a concise definition of strategies in order to realize next generation devices in this material system and to gain overall progress in the research field of quantum dot infrared photodetectors. The interpretation of the experimental results is supported by analytical and numerical simulations. The samples, grown by collaboration partners, were characterized using differential transmission and fast Fourier transform infrared spectroscopy, with a special emphasis on the latter one. Therefore, samples both in wedged waveguide geometry and samples with gold coated mesa structures have been processed. A large part of the discussion is dedicated to the current voltage characteristic of the devices, due to its large importance for device optimization, i.e. the reduction of the dark current plays a crucial role in the research field of high temperature infrared photon-detection. Further, results of photoluminescence measurements, performed by collaboration partners, have been used in order to attain a more complete picture of the samples' electronic band structure and in order to obtain complementary information with respect to other measurement methods applied within the experimental work and the simulation of the structures. In agreement to the simulations, a photocurrent response was observed at 6 and at 12 μm up to a temperature of 80 K, depending on the samples' design. The principle of parameter scaling was applied to the samples, in order to assign physical effects either to details in the samples' design or to technological quality aspects, i.e. the doping level and the thickness of the capping layer was varied. In addition to that a quantum well was introduced within a series of samples in order to

InN Quantum Dot Based Infra-Red Photodetectors.

Science.gov (United States)

Shetty, Arjun; Kumar, Mahesh; Roull, Basanta; Vinoy, K J; Krupanidhj, S B

2016-01-01

Self-assembled InN quantum dots (QDs) were grown on Si(111) substrate using plasma assisted molecular beam epitaxy (PA-MBE). Single-crystalline wurtzite structure of InN QDs was confirmed by X-ray diffraction. The dot densities were varied by varying the indium flux. Variation of dot density was confirmed by FESEM images. Interdigitated electrodes were fabricated using standard lithog- raphy steps to form metal-semiconductor-metal (MSM) photodetector devices. The devices show strong infrared response. It was found that the samples with higher density of InN QDs showed lower dark current and higher photo current. An explanation was provided for the observations and the experimental results were validated using Silvaco Atlas device simulator.

Germanium photodetectors fabricated on 300 mm silicon wafers for near-infrared focal plane arrays

Science.gov (United States)

Zeller, John W.; Rouse, Caitlin; Efstathiadis, Harry; Dhar, Nibir K.; Wijewarnasuriya, Priyalal; Sood, Ashok K.

2017-09-01

SiGe p-i-n photodetectors have been fabricated on 300 mm (12") diameter silicon (Si) wafers utilizing high throughput, large-area complementary metal-oxide semiconductor (CMOS) technologies. These Ge photodetectors are designed to operate in room temperature environments without cooling, and thus have potential size and cost advantages over conventional cooled infrared detectors. The two-step fabrication process for the p-i-n photodetector devices, designed to minimize the formation of defects and threading dislocations, involves low temperature epitaxial growth of a thin p+ (boron) Ge seed/buffer layer, followed by higher temperature deposition of a thicker Ge intrinsic layer. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated uniform layer compositions with well defined layer interfaces and reduced dislocation density. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) was likewise employed to analyze the doping levels of the p+ and n+ layers. Current-voltage (I-V) measurements demonstrated that these SiGe photodetectors, when exposed to incident visible-NIR radiation, exhibited dark currents down below 1 μA and significant enhancement in photocurrent at -1 V. The zero-bias photocurrent was also relatively high, showing a minimal drop compared to that at -1 V bias.

Development of Quantum Devices and Algorithms for Radiation Detection and Radiation Signal Processing

International Nuclear Information System (INIS)

El Tokhy, M.E.S.M.E.S.

2012-01-01

The main functions of spectroscopy system are signal detection, filtering and amplification, pileup detection and recovery, dead time correction, amplitude analysis and energy spectrum analysis. Safeguards isotopic measurements require the best spectrometer systems with excellent resolution, stability, efficiency and throughput. However, the resolution and throughput, which depend mainly on the detector, amplifier and the analog-to-digital converter (ADC), can still be improved. These modules have been in continuous development and improvement. For this reason we are interested with both the development of quantum detectors and efficient algorithms of the digital processing measurement. Therefore, the main objective of this thesis is concentrated on both 1. Study quantum dot (QD) devices behaviors under gamma radiation 2. Development of efficient algorithms for handling problems of gamma-ray spectroscopy For gamma radiation detection, a detailed study of nanotechnology QD sources and infrared photodetectors (QDIP) for gamma radiation detection is introduced. There are two different types of quantum scintillator detectors, which dominate the area of ionizing radiation measurements. These detectors are QD scintillator detectors and QDIP scintillator detectors. By comparison with traditional systems, quantum systems have less mass, require less volume, and consume less power. These factors are increasing the need for efficient detector for gamma-ray applications such as gamma-ray spectroscopy. Consequently, the nanocomposite materials based on semiconductor quantum dots has potential for radiation detection via scintillation was demonstrated in the literature. Therefore, this thesis presents a theoretical analysis for the characteristics of QD sources and infrared photodetectors (QDIPs). A model of QD sources under incident gamma radiation detection is developed. A novel methodology is introduced to characterize the effect of gamma radiation on QD devices. The rate

Uncooled infrared photodetectors in Poland

Science.gov (United States)

Piotrowski, J.; Piotrowski, A.

2006-03-01

The history and present status of the middle and long wavelength Hg1-xCdxTe infrared detectors in Poland are reviewed. Research and development efforts in Poland were concentrated mostly on uncooled market niche. Technology of the infrared photodetectors has been developed by several research groups. The devices are based on mercury-based variable band gap semiconductor alloys. Modified isothermal vapour phase epitaxy (ISOVPE) has been used for many years for research and commercial fabrication of photoconductive, photoelectromagnetic and other devices. Bulk growth and liquid phase epitaxy was also used. At present, the fabrication of IR devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition (MOCVD), frequently in combination with the ISOVPE. Photoconductive and photoelectromagnetic detectors are still in production. The devices are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, the PV devices could offer high performance and very fast response. At present, the uncooled long wavelength devices of conventional design suffer from two issues; namely low quantum efficiency and very low junction resistance. It makes them useless for practical applications. The problems have been solved with advanced 3D band gap engineered architecture, multiple cell heterojunction devices connected in series, monolithic integration of the detectors with microoptics and other improvements. Present fabrication program includes devices which are optimized for operation at any wavelength within a wide spectral range 1-15 μm and 200-300 K temperature range. Special solutions have been applied to improve speed of response. Some devices show picoseconds range response time. The devices have found numerous civilian and military applications.

Near-infrared sub-bandgap all-silicon photodetectors: state of the art and perspectives.

Science.gov (United States)

Casalino, Maurizio; Coppola, Giuseppe; Iodice, Mario; Rendina, Ivo; Sirleto, Luigi

2010-01-01

Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

Near-Infrared Sub-Bandgap All-Silicon Photodetectors: State of the Art and Perspectives

Directory of Open Access Journals (Sweden)

Luigi Sirleto

2010-11-01

Full Text Available Due to recent breakthroughs, silicon photonics is now the most active discipline within the field of integrated optics and, at the same time, a present reality with commercial products available on the market. Silicon photodiodes are excellent detectors at visible wavelengths, but the development of high-performance photodetectors on silicon CMOS platforms at wavelengths of interest for telecommunications has remained an imperative but unaccomplished task so far. In recent years, however, a number of near-infrared all-silicon photodetectors have been proposed and demonstrated for optical interconnect and power-monitoring applications. In this paper, a review of the state of the art is presented. Devices based on mid-bandgap absorption, surface-state absorption, internal photoemission absorption and two-photon absorption are reported, their working principles elucidated and their performance discussed and compared.

Perovskite photodetectors with both visible-infrared dual-mode response and super-narrowband characteristics towards photo-communication encryption application.

Science.gov (United States)

Wu, Ye; Li, Xiaoming; Wei, Yi; Gu, Yu; Zeng, Haibo

2017-12-21

Photo-communication has attracted great attention because of the rapid development of wireless information transmission technology. However, it is still a great challenge in cryptography communications, where it is greatly weakened by the openness of the light channels. Here, visible-infrared dual-mode narrowband perovskite photodetectors were fabricated and a new photo-communication encryption technique was proposed. For the first time, highly narrowband and two-photon absorption (TPA) resultant photoresponses within a single photodetector are demonstrated. The full width at half maximum (FWHM) of the photoresponse is as narrow as 13.6 nm in the visible range, which is superior to state-of-the-art narrowband photodetectors. Furthermore, these two merits of narrowband and TPA characteristics are utilized to encrypt the photo-communication based on the above photodetectors. When sending information and noise signals with 532 and 442 nm laser light simultaneously, the perovskite photodetectors only receive the main information, while the commercial Si photodetector responds to both lights, losing the main information completely. The final data are determined by the secret key through the TPA process as preset. Such narrowband and TPA detection abilities endow the perovskite photodetectors with great potential in future security communication and also provide new opportunities and platforms for encryption techniques.

A Thermal-Electrically Cooled Quantum-Dot Middle-Wave Infrared Photodetector with High Quantum Efficiency and Photodetectivity, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Middle-wave infrared (LWIR, 3.2-3.6 m) photodetectors with a high specific photodetectivity (D*) are of great importance in NASA's lidar and remote sensing...

Photodetector of ultraviolet radiation

International Nuclear Information System (INIS)

Dorogan, V.; Branzari, V.; Vieru, T.; Manole, M.; Canter, V.

2000-01-01

The invention relates to photodetectors on base of semiconductors of ultraviolet radiation and may be used in optoelectronic system for determining the intensity and the dose of ultraviolet radiation emitted by the Sun or other sources. Summary of the invention consists in the fact that in the photodetector of ultraviolet radiation the superficial potential barrier is divided into two identical elements, electrically isolated each of the other, one of them being covered with a layer of transparent material for visible and infrared radiation and absorption the ultra violet radiation. The technical result consists in mutual compensation of visible and infrared components of the radiation spectrum

Colloidal quantum dot photodetectors

KAUST Repository

Konstantatos, Gerasimos; Sargent, Edward H.

2011-01-01

in particular on visible-, near-infrared, and short-wavelength infrared photodetectors based on size-effect-tuned semiconductor nanoparticles made using quantum-confined PbS, PbSe, Bi 2S3, and In2S3. These devices have in recent years achieved room-temperature D

Corrugated Quantum Well Infrared Photodetector Focal Plane Array Test Results

Science.gov (United States)

Goldberg, A.; Choi, K. K.; Das, N. C.; La, A.; Jhabvala, M.

1999-01-01

The corrugated quantum-well infrared photodetector (C-QWIP) uses total internal reflection to couple normal incident light into the optically active quantum wells. The coupling efficiency has been shown to be relatively independent of the pixel size and wavelength thus making the C-QWIP a candidate for detectors over the entire infrared spectrum. The broadband coupling efficiency of the C-QWIP makes it an ideal candidate for multiwavelength detectors. We fabricated and tested C-QWIP focal plane arrays (FPAs) with cutoff wavelengths of 11.2 and 16.2 micrometers. Each FPA has 256 x 256 pixels that are bump-bonded to a direct injection readout circuit. Both FPAs provided infrared imagery with good aesthetic attributes. For the 11.2-micrometers FPA, background-limited performance (BLIP) was observed at 60 K with f/3 optics. For the 16.2-micrometers FPA, BLIP was observed at 38 K. Besides the reduction of dark current in C-QWIP structures, the measured internal quantum efficiency (eta) remains to be high. The values for responsivity and quantum efficiency obtained from the FPA results agree well with those measured for single devices.

Room-temperature InP/InAsP Quantum Discs-in-Nanowire Infrared Photodetectors.

Science.gov (United States)

Karimi, Mohammad; Jain, Vishal; Heurlin, Magnus; Nowzari, Ali; Hussain, Laiq; Lindgren, David; Stehr, Jan Eric; Buyanova, Irina A; Gustafsson, Anders; Samuelson, Lars; Borgström, Magnus T; Pettersson, Håkan

2017-06-14

The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication, and optoelectronic properties of infrared photodetectors comprising four million n + -i-n + InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in the i-segment. By Zn compensation of the residual n-dopants in the i-segment, the room-temperature dark current is strongly suppressed to a level of pA/NW at 1 V bias. The low dark current is manifested in the spectrally resolved photocurrent measurements, which reveal strong photocurrent contributions from the InAsP quantum discs at room temperature with a threshold wavelength of about 2.0 μm and a bias-tunable responsivity reaching 7 A/W@1.38 μm at 2 V bias. Two different processing schemes were implemented to study the effects of radial self-gating in the nanowires induced by the nanowire/SiO x /ITO wrap-gate geometry. Summarized, our results show that properly designed axial InP/InAsP nanowire heterostructures are promising candidates for broadband photodetectors.

Role of the wetting layer in the enhanced responsivity of InAs/GaAsSb quantum dot infrared photodetectors

Energy Technology Data Exchange (ETDEWEB)

Guzmán, Álvaro, E-mail: guzman@die.upm.es; Yamamoto, Kenji; Ulloa, J. M.; Hierro, Adrian [Instituto de Sistemas Optoelectrónicos y Microtecnología y Dept. Ingeniería Electrónica, Universidad Politécnica de Madrid, ETSI de Telecomunicación, Avda. Complutense 30, 28040 Madrid (Spain); Llorens, J. M. [IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid (Spain)

2015-07-06

InAs/GaAs{sub 1−x}Sb{sub x} Quantum Dot (QD) infrared photodetectors are analyzed by photocurrent spectroscopy. We observe that the integrated responsivity of the devices is improved with the increasing Sb mole fraction in the capping layer, up to 4.2 times for x = 17%. Since the QD layers are not vertically aligned, the vertical transport of the carriers photogenerated within the QDs takes place mainly through the bulk material and the wetting layer of the additional QD regions. The lower thickness of the wetting layer for high Sb contents results in a reduced capture probability of the photocarriers, thus increasing the photoconductive gain and hence, the responsivity of the device. The growth of not vertically aligned consecutive QD layers with a thinner wetting layer opens a possibility to improve the performance of quantum dot infrared photodetectors.

Ultrasensitive near-infrared photodetectors based on graphene-MoTe2-graphene vertical van der Waals heterostructure

Science.gov (United States)

Zhang, Kun; Ye, Yu; Dai, Lun; School of Physics, Peking University Team

Two-dimensional (2D) materials have rapidly established themselves as exceptional building blocks for optoelectronic applications, due to their unique properties and atomically thin nature. Nevertheless, near-infrared (NIR) photodetectors based on layered 2D semiconductors are rarely realized. In this work, we fabricate graphene-MoTe2-graphene vertical vdWs heterostructure by a facile and reliable site controllable transfer method, and apply it for photodetection from visible to the NIR wavelength range. Compared to the 2D semiconductor based photodetectors reported thus far, the graphene-MoTe2-graphene photodetector has superior performance, including high photoresponsivity (110 mA W-1 at 1064 nm and 205 mA W-1 at 473 nm), high external quantum efficiency (EQE, 12.9% at 1064 nm and 53.8% at 473 nm), rapid response and recovery processes (rise time of 24 μs, fall time of 46 μs under 1064 nm illumination), and free from an external source-drain power supply. The all-2D-materials heterostructure has promising applications in future novel high responsivity, high speed and flexible NIR devices.

Near-infrared responsive PbS-sensitized photovoltaic photodetectors fabricated by the spin-assisted successive ionic layer adsorption and reaction method

International Nuclear Information System (INIS)

Im, Sang Hyuk; Kim, Hi-jung; Seok, Sang Il

2011-01-01

A PbS-sensitized photovoltaic photodetector responsive to near-infrared (NIR) light was fabricated by depositing monolayered PbS nanoparticles on a mesoporous TiO 2 (mp-TiO 2 ) film via the spin-assisted successive ionic layer adsorption and reaction (SILAR) method. By adjusting the size and morphology of the PbS nanoparticles through repeated spin-assisted SILAR cycles, the PbS-sensitized photovoltaic photodetector achieved an external quantum efficiency of 9.3% at 1140 nm wavelength and could process signals up to 1 kHz.

Angular-dependent photodetection enhancement by a metallic circular disk optical antenna

Directory of Open Access Journals (Sweden)

Thitikorn Kemsri

2017-02-01

Full Text Available In this paper, we analyze the plasmonic resonance excited by linearly polarized longwave infrared (LWIR plane waves in a metallic circular disk optical antenna (MCDA. The surface current distributions are simulated at different wavelengths, incident angles, and polarizations. The excited surface plasmonic resonance waves (SPRs are different from the Bessel-type of SPR modes and closely resemble those in a monopole antenna. An MCDA coupled LWIR quantum dot infrared photodetector (QDIP was fabricated and measured at different LWIR plane wave wavelengths and incident angles. A linear correlation between the enhancement ratio and the integrated square of the current is obtained, indicating the monopole antenna effect is a dominating factor for the plasmonic enhancement.

Near infrared photodetector based on polymer and indium nitride nanorod organic/inorganic hybrids

International Nuclear Information System (INIS)

Lai, Wei-Jung; Li, Shao-Sian; Lin, Chih-Cheng; Kuo, Chun-Chiang; Chen, Chun-Wei; Chen, Kuei-Hsien; Chen, Li-Chyong

2010-01-01

We propose a nanostructured near infrared photodetector based on indium nitride (InN) nanorod/poly(3-hexylthiophene) hybrids. The current-voltage characteristic of the hybrid device demonstrates the typical p-n heterojunction diode behavior, consisting of p-type polymer and n-type InN nanorods. The device shows a photoresponse range of 900-1260 nm under various reverse biases. An external quantum efficiency of 3.4% at 900 nm operated at -10 V reverse bias was obtained, which is comparable with devices based on lead sulfide and lead selenide hybrid systems.

Near-infrared responsive PbS-sensitized photovoltaic photodetectors fabricated by the spin-assisted successive ionic layer adsorption and reaction method

Energy Technology Data Exchange (ETDEWEB)

Im, Sang Hyuk; Kim, Hi-jung; Seok, Sang Il, E-mail: seoksi@krict.re.kr [KRICT-EPFL Global Research Laboratory, Advanced Materials Division, Korea Research Institute of Chemical Technology, 19 Sinseongno, Yuseong, Daejeon 305-600 (Korea, Republic of)

2011-09-30

A PbS-sensitized photovoltaic photodetector responsive to near-infrared (NIR) light was fabricated by depositing monolayered PbS nanoparticles on a mesoporous TiO{sub 2} (mp-TiO{sub 2}) film via the spin-assisted successive ionic layer adsorption and reaction (SILAR) method. By adjusting the size and morphology of the PbS nanoparticles through repeated spin-assisted SILAR cycles, the PbS-sensitized photovoltaic photodetector achieved an external quantum efficiency of 9.3% at 1140 nm wavelength and could process signals up to 1 kHz.

Background–limited long wavelength infrared InAs/InAs1− xSbx type-II superlattice-based photodetectors operating at 110 K

Directory of Open Access Journals (Sweden)

Abbas Haddadi

2017-03-01

Full Text Available We report the demonstration of high-performance long-wavelength infrared (LWIR nBn photodetectors based on InAs/InAs1− xSbx type-II superlattices. A new saw-tooth superlattice design was used to implement the electron barrier of the photodetectors. The device exhibited a cut-off wavelength of ∼10 μ m at 77 K. The photodetector exhibited a peak responsivity of 2.65 A/W, corresponding to a quantum efficiency of 43%. With an R × A of 664 Ω · cm 2 and a dark current density of 8 × 10−5 A/cm2, under −80 mV bias voltage at 77 K, the photodetector exhibited a specific detectivity of 4.72 × 1011 cm· Hz / W and a background–limited operating temperature of 110 K.

Self-Powered UV-Near Infrared Photodetector Based on Reduced Graphene Oxide/n-Si Vertical Heterojunction.

Science.gov (United States)

Li, Guanghui; Liu, Lin; Wu, Guan; Chen, Wei; Qin, Sujie; Wang, Yi; Zhang, Ting

2016-09-01

A novel self-powered photodetector based on reduced graphene oxide (rGO)/n-Si p-n vertical heterojunction with high sensitivity and fast response time is presented. The photodetector contains a p-n vertical heterojunction between a drop-casted rGO thin film and n-Si. Contacts between the semiconductor layer (rGO, n-Si) and source-drain Ti/Au electrodes allow efficient transfer of photogenerated charge carriers. The self-powered UV-near infrared photodetector shows high sensitivity toward a spectrum of light from 365 to 1200 nm. Under the 600 nm illumination (0.81 mW cm -2 ), the device has a photoresponsivity of 1.52 A W -1 , with fast response and recover time (2 ms and 3.7 ms), and the ON/OFF ratios exceed 10 4 when the power density reaches ≈2.5 mW cm -2 . The high photoresponse primarily arises from the built-in electric field formed at the interface of n-Si and rGO film. The effect of rGO thickness, rGO reduction level, and layout of rGO/n-Si effective contact area on device performance are also systematically investigated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mid-wavelength infrared unipolar nBp superlattice photodetector

Science.gov (United States)

Kazemi, Alireza; Myers, Stephen; Taghipour, Zahra; Mathews, Sen; Schuler-Sandy, Ted; Lee, Seunghyun; Cowan, Vincent M.; Garduno, Eli; Steenbergen, Elizabeth; Morath, Christian; Ariyawansa, Gamini; Scheihing, John; Krishna, Sanjay

2018-01-01

We report a Mid-Wavelength Infrared (MWIR) barrier photodetector based on the InAs/GaSb/AlSb type-II superlattice (T2SL) material system. The nBp design consists of a single unipolar barrier (InAs/AlSb SL) placed between a 4 μm thick p-doped absorber (InAs/GaSb SL) and an n-type contact layer (InAs/GaSb SL). At 80 K, the device exhibited a 50% cut-off wavelength of 5 μm, was fully turned-ON at zero bias and the measured QE was 50% (front side illumination with no AR coating) at 4.5 μm with a dark current density of 4.7 × 10-6 A/cm2 at Vb = 50 mV. At 150 K and Vb = 50 mV, the 50% cut-off wavelength increased to 5.3 μm, and the QE was 54% at 4.5 μm with a dark current of 5.0 × 10-4 A/cm2.

Minority carrier lifetime and dark current measurements in mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetectors

Science.gov (United States)

Olson, B. V.; Kim, J. K.; Kadlec, E. A.; Klem, J. F.; Hawkins, S. D.; Leonhardt, D.; Coon, W. T.; Fortune, T. R.; Cavaliere, M. A.; Tauke-Pedretti, A.; Shaner, E. A.

2015-11-01

Carrier lifetime and dark current measurements are reported for a mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetector. Minority carrier lifetimes are measured using a non-contact time-resolved microwave technique on unprocessed portions of the nBn wafer and the Auger recombination Bloch function parameter is determined to be |F1F2|=0.292 . The measured lifetimes are also used to calculate the expected diffusion dark current of the nBn devices and are compared with the experimental dark current measured in processed photodetector pixels from the same wafer. Excellent agreement is found between the two, highlighting the important relationship between lifetimes and diffusion currents in nBn photodetectors.

Cryogenic photodetectors

Science.gov (United States)

Chardin, G.

2000-03-01

Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

Cryogenic photodetectors

CERN Document Server

Chardin, G

2000-01-01

Some of the most significant developments in cryogenic photodetectors are presented. In particular, the main characteristics of microbolometers involving Transition Edge- and NTD-sensors and offering resolutions of a few eV in the keV range, superconducting tunnel junction detectors with resolutions of the order of 10 eV or offering position sensitivity, and infrared bolometers with recent developments towards matrix detectors are discussed. Some of the recent achievements using large mass bolometers for gamma and neutron discriminating detectors, and future prospects of single photon detection in the far infrared using Single Electron Transistor devices are also presented.

Progress on type-II InAs/GaSb superlattice (T2SL) infrared photodetector : from MWIR to VLWIR spectral domains

Science.gov (United States)

Christol, P.; Rodriguez, J.-B.

2017-11-01

Infrared photodetectors based on type-II InAs/GaSb superlattice (T2SL) material has been given a lot of attention this past decade, in particular by U.S. laboratories. Among the advantages of this material system, one can cite the possibility to span a large Infrared (IR) range (3μm to 30 μm) by tailoring the band-gap independently from the lattice constant, allowing addressing many applications by the same fabrication process and the realization of multi-color IR sensors for high performance imaging systems. Recently, the maturity of the growth of the quantum structure by molecular beam epitaxy (MBE) and progress on the processing resulted in the demonstration of high-performance mega-pixel focal plane arrays (FPA) in both the mid-wavelength (MWIR) and the long-wavelength (LWIR) infrared spectral bands [1]. Consequently, InAs/GaSb T2SL photodetector can be now considered as a new infrared technology which can be complementary to InSb, MCT or QWIPs technologies. After some reminders on InAs/GaSb T2SL quantum structure properties, we present in this communication the results obtained by the IES laboratory, from Montpellier University, France, for photodiodes operating in the MWIR spectral domains. We then complete the paper by the main results reached by others laboratories for T2SL detectors operating from MWIR to VLWIR spectral ranges.

Measurements of Low Frequency Noise of Infrared Photo-Detectors with Transimpedance Detection System

Directory of Open Access Journals (Sweden)

Ciura Łukasz

2014-08-01

Full Text Available The paper presents the method and results of low-frequency noise measurements of modern mid-wavelength infrared photodetectors. A type-II InAs/GaSb superlattice based detector with nBn barrier architecture is compared with a high operating temperature (HOT heterojunction HgCdTe detector. All experiments were made in the range 1 Hz - 10 kHz at various temperatures by using a transimpedance detection system, which is examined in detail. The power spectral density of the nBn’s dark current noise includes Lorentzians with different time constants while the HgCdTe photodiode has more uniform 1/f - shaped spectra. For small bias, the low-frequency noise power spectra of both devices were found to scale linearly with bias voltage squared and were connected with the fluctuations of the leakage resistance. Leakage resistance noise defines the lower noise limit of a photodetector. Other dark current components give raise to the increase of low-frequency noise above this limit. For the same voltage biasing devices, the absolute noise power densities at 1 Hz in nBn are 1 to 2 orders of magnitude lower than in a MCT HgCdTe detector. In spite of this, low-frequency performance of the HgCdTe detector at ~ 230K is still better than that of InAs/GaSb superlattice nBn detector.

Mid-infrared two-photon absorption in an extended-wavelength InGaAs photodetector

Science.gov (United States)

Piccardo, Marco; Rubin, Noah A.; Meadowcroft, Lauren; Chevalier, Paul; Yuan, Henry; Kimchi, Joseph; Capasso, Federico

2018-01-01

We investigate the nonlinear optical response of a commercial extended-wavelength In0.81Ga0.19As uncooled photodetector. Degenerate two-photon absorption in the mid-infrared range is observed using a quantum cascade laser emitting at λ = 4.5 μm as the excitation source. From the measured two-photon photocurrent signal, we extract a two-photon absorption coefficient β(2) = 0.6 ± 0.2 cm/MW, in agreement with the theoretical value obtained from the Eg-3 scaling law. Considering the wide spectral range covered by extended-wavelength InxGa1-xAs alloys, this result holds promise for applications based on two-photon absorption for this family of materials at wavelengths between 1.8 and 5.6 μm.

Mid-infrared GaSb-based resonant tunneling diode photodetectors for gas sensing applications

Science.gov (United States)

Rothmayr, F.; Pfenning, A.; Kistner, C.; Koeth, J.; Knebl, G.; Schade, A.; Krueger, S.; Worschech, L.; Hartmann, F.; Höfling, S.

2018-04-01

We present resonant tunneling diode-photodetectors (RTD-PDs) with GaAs0.15Sb0.85/AlAs0.1Sb0.9 double barrier structures combined with an additional quaternary Ga0.64In0.36As0.33Sb0.67 absorption layer covering the fingerprint absorption lines of various gases in the mid-infrared wavelength spectral region. The absorption layer cut-off wavelength is determined to be 3.5 μm, and the RTD-PDs show peak-to-valley current ratios up to 4.3 with a peak current density of 12 A/cm-2. The incorporation of the quaternary absorption layer enables the RTD-PDs to be sensitive to illumination with light up to the absorption lines of HCl at 3395 nm. At this wavelength, the detector shows a responsivity of 6.3 mA/W. At the absorption lines of CO2 and CO at 2004 nm and 2330 nm, respectively, the RTD-PDs reach responsivities up to 0.97 A/W. Thus, RTD-PDs pave the way towards high sensitive mid-infrared detectors that can be utilized in tunable laser absorption spectroscopy.

Peak response wavelengths of p- and n-type InxGa1-xAs-InP quantum well infrared photodetectors

International Nuclear Information System (INIS)

Fu, Y.; Willander, M.; Sengupta, D.K.

2005-01-01

p- and n-type In x Ga 1-x As-InP quantum wells are suitable for multi-color infrared photodetector applications in atmospheric windows due to improved barrier quality and carrier-transport properties. We apply the k.p method to study the energy band structures and optical transition properties, which show that the peak response wavelengths of p- and n-type In x Ga 1-x As-InP quantum well infrared photodetectors (QWIPs) are determined not only by the energy distance from the ground sublevels in the quantum well to the energy band edges of extended states, but also by the characteristics of the extended states. The optical phonon scattering process converts the broad absorption spectrum of the p-QWIP from 0 to 16 μm into a short-wavelength spectrum centered at 4.5 μm. The transport of electrons in the extended states of the n-QWIP is characterized by running wave boundary conditions, resulting in a theoretically optimal absorption rate by a 8-nm-thick In 0.53 Ga 0.47 As quantum well. Moreover, a conduction-band offset of 0.5 for an In x Ga 1-x As-InP (x=0.53) heterostructure gives the best data fitting of theoretical and experimental response peaks, whereas 0.55 is generally recommended in the literature. (orig.)

Enhancement of device performance by using quaternary capping over ternary capping in strain-coupled InAs/GaAs quantum dot infrared photodetectors

International Nuclear Information System (INIS)

Tongbram, B.; Shetty, S.; Ghadi, H.; Adhikary, S.; Chakrabarti, S.

2015-01-01

We investigate and compare the performance of 30 layers strain-coupled quantum dot (SCQD) infrared photodetectors capped with one of two different layers: a quaternary (In 0.21 Al 0.21 Ga 0.58 As) or ternary (In 0.15 Ga 0.85 As) alloy of 30 Aa and a GaAs layer with a thickness of 120-150 Aa. Measurements of optical properties, spectral responsivity, and cross-sectional transmission electron microscopy were conducted. Results showed that quaternary capping yielded more superior multilayer QD infrared photodetectors than ternary capping. Quaternary capping resulted in enhanced dot size, order, and uniformity of the QD array. The presence of Al in the capped layer helped in the reduction in dark current density and spectral linewidth as well as led to higher electron confinement of the QDs and enhanced device detectivity. The vertically ordered SCQD system with quaternary capping exhibited higher peak detectivity (∝10 10 cm Hz 1/2 /W) than that with ternary capping (∝10 7 cm Hz 1/2 /W). In addition, a very low noise current density of ∝10 -16 A/cm 2 Hz 1/2 at 77 K was achieved with quaternary-capped QDs. (orig.)

High intersubband absorption in long-wave quantum well infrared photodetector based on waveguide resonance

Science.gov (United States)

Zheng, Yuanliao; Chen, Pingping; Ding, Jiayi; Yang, Heming; Nie, Xiaofei; Zhou, Xiaohao; Chen, Xiaoshuang; Lu, Wei

2018-06-01

A hybrid structure consisting of periodic gold stripes and an overlaying gold film has been proposed as the optical coupler of a long-wave quantum well infrared photodetector. Absorption spectra and field distributions of the structure at back-side normal incidence are calculated by the finite difference time-domain method. The results indicate that the intersubband absorption can be greatly enhanced based on the waveguide resonance as well as the surface plasmon polariton (SPP) mode. With the optimized structural parameters of the periodic gold stripes, the maximal intersubband absorption can exceed 80%, which is much higher than the SPP-enhanced intersubband absorption (the one of the standard device. The relationship between the structural parameters and the waveguide resonant wavelength is derived. Other advantages of the efficient optical coupling based on waveguide resonance are also discussed.

Two color photodetector using an asymmetric quantum well structure

OpenAIRE

Lantz, Kevin R.

2002-01-01

Approved for public release; distribution is unlimited The past twenty years have seen an explosion in the realm of infrared detection technology fueled by improvements in III-V semiconductor technology and by new semiconductor growth methods. One of the fastest growing areas of this research involves the use of bandgap engineering in order to create artificial quantum wells for use in Quantum Well Infrared Photodetectors (QWIPs). QWIPs have an advantage over other infrared detectors such ...

Highly sensitive MOS photodetector with wide band responsivity assisted by nanoporous anodic aluminum oxide membrane.

Science.gov (United States)

Chen, Yungting; Cheng, Tzuhuan; Cheng, Chungliang; Wang, Chunhsiung; Chen, Chihwei; Wei, Chihming; Chen, Yangfang

2010-01-04

A new approach for developing highly sensitive MOS photodetector based on the assistance of anodic aluminum oxide (AAO) membrane is proposed, fabricated, and characterized. It enables the photodetector with the tunability of not only the intensity but also the range of the response. Under a forward bias, the response of the MOS photodetector with AAO membrane covers the visible as well as infrared spectrum; however, under a reverse bias, the near-infrared light around Si band edge dominates the photoresponse. Unlike general MOS photodetectors which only work under a reverse bias, our MOS photodetectors can work even under a forward bias, and the responsivity at the optical communication wavelength of 850nm can reach up to 0.24 A/W with an external quantum efficiency (EQE) of 35%. Moreover, the response shows a large enhancement factor of 10 times at 1050 nm under a reverse bias of 0.5V comparing with the device without AAO membrane. The underlying mechanism for the novel properties of the newly designed device has been proposed.

Resonant quantum efficiency enhancement of midwave infrared nBn photodetectors using one-dimensional plasmonic gratings

International Nuclear Information System (INIS)

Nolde, Jill A.; Kim, Chul Soo; Jackson, Eric M.; Ellis, Chase T.; Abell, Joshua; Glembocki, Orest J.; Canedy, Chadwick L.; Tischler, Joseph G.; Vurgaftman, Igor; Meyer, Jerry R.; Aifer, Edward H.; Kim, Mijin

2015-01-01

We demonstrate up to 39% resonant enhancement of the quantum efficiency (QE) of a low dark current nBn midwave infrared photodetector with a 0.5 μm InAsSb absorber layer. The enhancement was achieved by using a 1D plasmonic grating to couple incident light into plasmon modes propagating in the plane of the device. The plasmonic grating is composed of stripes of deposited amorphous germanium overlaid with gold. Devices with and without gratings were processed side-by-side for comparison of their QEs and dark currents. The peak external QE for a grating device was 29% compared to 22% for a mirror device when the illumination was polarized perpendicularly to the grating lines. Additional experiments determined the grating coupling efficiency by measuring the reflectance of analogous gratings deposited on bare GaSb substrates

Colloidal quantum dot photodetectors

KAUST Repository

Konstantatos, Gerasimos

2011-05-01

We review recent progress in light sensors based on solution-processed materials. Spin-coated semiconductors can readily be integrated with many substrates including as a post-process atop CMOS silicon and flexible electronics. We focus in particular on visible-, near-infrared, and short-wavelength infrared photodetectors based on size-effect-tuned semiconductor nanoparticles made using quantum-confined PbS, PbSe, Bi 2S3, and In2S3. These devices have in recent years achieved room-temperature D values above 1013 Jones, while fully-depleted photodiodes based on these same materials have achieved MHz response combined with 1012 Jones sensitivities. We discuss the nanoparticle synthesis, the materials processing, integrability, temperature stability, physical operation, and applied performance of this class of devices. © 2010 Elsevier Ltd. All rights reserved.

Advances in the characterization of InAs/GaSb superlattice infrared photodetectors

Science.gov (United States)

Wörl, A.; Daumer, V.; Hugger, T.; Kohn, N.; Luppold, W.; Müller, R.; Niemasz, J.; Rehm, R.; Rutz, F.; Schmidt, J.; Schmitz, J.; Stadelmann, T.; Wauro, M.

2016-10-01

This paper reports on advances in the electro-optical characterization of InAs/GaSb short-period superlattice infrared photodetectors with cut-off wavelengths in the mid-wavelength and long-wavelength infrared ranges. To facilitate in-line monitoring of the electro-optical device performance at different processing stages we have integrated a semi-automated cryogenic wafer prober in our process line. The prober is configured for measuring current-voltage characteristics of individual photodiodes at 77 K. We employ it to compile a spatial map of the dark current density of a superlattice sample with a cut-off wavelength around 5 μm patterned into a regular array of 1760 quadratic mesa diodes with a pitch of 370 μm and side lengths varying from 60 to 350 μm. The different perimeter-to-area ratios make it possible to separate bulk current from sidewall current contributions. We find a sidewall contribution to the dark current of 1.2×10-11 A/cm and a corrected bulk dark current density of 1.1×10-7 A/cm2, both at 200 mV reverse bias voltage. An automated data analysis framework can extract bulk and sidewall current contributions for various subsets of the test device grid. With a suitable periodic arrangement of test diode sizes, the spatial distribution of the individual contributions can thus be investigated. We found a relatively homogeneous distribution of both bulk dark current density and sidewall current contribution across the sample. With the help of an improved capacitance-voltage measurement setup developed to complement this technique a residual carrier concentration of 1.3×1015 cm-3 is obtained. The work is motivated by research into high performance superlattice array sensors with demanding processing requirements. A novel long-wavelength infrared imager based on a heterojunction concept is presented as an example for this work. It achieves a noise equivalent temperature difference below 30 mK for realistic operating conditions.

Highly sensitive PMOS photodetector with wide band responsivity assisted by nanoporous anodic aluminum oxide membrane

Science.gov (United States)

Chen, Yung Ting; Chen, Yang Fang

2010-03-01

A new approach for developing highly sensitive PMOS photodetector based on the assistance of AAO membrane is proposed, fabricated, and characterized. It enables the photodetector with the tunability of not only the intensity but also the range of the response. Under a forward bias, the response of the PMOS photodetector with AAO membrane covers the visible as well as infrared spectrum; however, under a reverse bias, the near-infrared light around Si band edge dominates the photoresponse. Notably, the response at the optical communication wavelength of 850 nm can reach up to 0.24 A/W with an external quantum efficiency of 35%. Moreover, the response shows a large enhancement factor of 10 times at 1050 nm under a reverse bias of 0.5 V comparing with the device without AAO membrane. The underlying mechanism for the novel properties of the newly designed device has been proposed.

Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors

International Nuclear Information System (INIS)

Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A.

2014-01-01

A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped

Comment on 'Local responsivity in quantum well photodetectors'

International Nuclear Information System (INIS)

Ryzhii, M.; Khmyrova, I.

2001-01-01

The response of multiple quantum well (QW) infrared photodetectors (QW) to the photoexcitation of one QW selected from many identical QWs was recently modeled [M. Ershov, J. Appl. Phys. 86, 7059 (1999)]. We point out here that the presented analysis based on the use of drift-diffusion model for a system with a few electrons is incorrect. [copyright] 2001 American Institute of Physics

Design and fabrication of resonator-quantum well infrared photodetector for SF6 gas sensor application

Science.gov (United States)

Sun, Jason; Choi, Kwong-Kit; DeCuir, Eric; Olver, Kimberley; Fu, Richard

2017-07-01

The infrared absorption of SF6 gas is narrowband and peaks at 10.6 μm. This narrowband absorption posts a stringent requirement on the corresponding sensors as they need to collect enough signal from this limited spectral bandwidth to maintain a high sensitivity. Resonator-quantum well infrared photodetectors (R-QWIPs) are the next generation of QWIP detectors that use resonances to increase the quantum efficiency for more efficient signal collection. Since the resonant approach is applicable to narrowband as well as broadband, it is particularly suitable for this application. We designed and fabricated R-QWIPs for SF6 gas detection. To achieve the expected performance, the detector geometry must be produced according to precise specifications. In particular, the height of the diffractive elements and the thickness of the active resonator must be uniform, and accurately realized to within 0.05 μm. Additionally, the substrates of the detectors must be completely removed to prevent the escape of unabsorbed light in the detectors. To achieve these specifications, two optimized inductively coupled plasma etching processes were developed. Due to submicron detector feature sizes and overlay tolerance, we used an advanced semiconductor material lithography stepper instead of a contact mask aligner to pattern wafers. Using these etching techniques and tool, we have fabricated focal plane arrays with 30-μm pixel pitch and 320×256 format. The initial test revealed promising results.

Self-Powered, Flexible, and Solution-Processable Perovskite Photodetector Based on Low-Cost Carbon Cloth.

Science.gov (United States)

Sun, Haoxuan; Lei, Tianyu; Tian, Wei; Cao, Fengren; Xiong, Jie; Li, Liang

2017-07-01

Flexible perovskite photodetectors are usually constructed on indium-tin-oxide-coated polymer substrates, which are expensive, fragile, and not resistant to high temperature. Herein, for the first time, a high-performance flexible perovskite photodetector is fabricated based on low-cost carbon cloth via a facile solution processable strategy. In this device, perovskite microcrystal and Spiro-OMeTAD (hole transporting material) blended film act as active materials for light detection, and carbon cloth serves as both a flexible substrate and a conductive electrode. The as-fabricated photodetector shows a broad spectrum response from ultraviolet to near-infrared light, high responsivity, fast response speed, long-term stability, and self-powered capability. Flexible devices show negligible degradation after several tens of bending cycles and at the extremely bending angle of 180°. This work promises a new technique to construct flexible, high-performance photodetectors with low cost and self-powered capability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Traveling-wave photodetector

Science.gov (United States)

Hietala, V.M.; Vawter, G.A.

1993-12-14

The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size. 4 figures.

Effect of preliminary annealing of silicon substrates on the spectral sensitivity of photodetectors in bipolar integrated circuits

International Nuclear Information System (INIS)

Blynskij, V.I.; Bozhatkin, O.A.; Golub, E.S.; Lemeshevskaya, A.M.; Shvedov, S.V.

2010-01-01

We examine the results of an effect of preliminary annealing on the spectral sensitivity of photodetectors in bipolar integrated circuits, formed in silicon grown by the Czochralski method. We demonstrate the possibility of substantially improving the sensitivity of photodetectors in the infrared region of the spectrum with twostep annealing. The observed effect is explained by participation of oxidation in the gettering process, where oxidation precedes formation of a buried n + layer in the substrate. (authors)

Topological insulator infrared pseudo-bolometer with polarization sensitivity

Energy Technology Data Exchange (ETDEWEB)

Sharma, Peter Anand

2017-10-25

Topological insulators can be utilized in a new type of infrared photodetector that is intrinsically sensitive to the polarization of incident light and static magnetic fields. The detector isolates single topological insulator surfaces and allows light collection and exposure to static magnetic fields. The wavelength range of interest is between 750 nm and about 100 microns. This detector eliminates the need for external polarization selective optics. Polarization sensitive infrared photodetectors are useful for optoelectronics applications, such as light detection in environments with low visibility in the visible wavelength regime.

Ultrasensitive solution-cast quantum dot photodetectors

International Nuclear Information System (INIS)

Konstantatos, G.; Howard, I.; Fischer, A.; Hoogland, S.; Clifford, J.; Klem, E.; Levina, L.; Sargent, E.H.

2007-01-01

Solution-processed electronic and optoelectronic devices offer low cost, large device area, physical flexibility and convenient materials integration compared to conventional epitaxially grown, lattice-matched, crystalline semiconductor devices. Although the electronic or optoelectronic performance of these solution-processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. Here we report the fabrication of solution-processed infrared photodetectors that are superior in their normalized detectivity (D * , the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temperature. We produced the devices in a single solution-processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of Pbs colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 10 3 AW -1 . The best devices exhibited a normalized detectivity D * of 1.8 x 10 13 jones (1 jones= 1 cm Hz 1/2 W -1 ) at 1.3μm at room temperature: today's highest performance infrared photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D * in the 10 12 ) jones range at room temperature, whereas the previous record for D * from a photoconductive detector lies at 10 11 jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices. (author)

Electronic band structures and optical properties of type-II superlattice photodetectors with interfacial effect.

Science.gov (United States)

Qiao, Peng-Fei; Mou, Shin; Chuang, Shun Lien

2012-01-30

The electronic band structures and optical properties of type-II superlattice (T2SL) photodetectors in the mid-infrared (IR) range are investigated. We formulate a rigorous band structure model using the 8-band k · p method to include the conduction and valence band mixing. After solving the 8 × 8 Hamiltonian and deriving explicitly the new momentum matrix elements in terms of envelope functions, optical transition rates are obtained through the Fermi's golden rule under various doping and injection conditions. Optical measurements on T2SL photodetectors are compared with our model and show good agreement. Our modeling results of quantum structures connect directly to the device-level design and simulation. The predicted doping effect is readily applicable to the optimization of photodetectors. We further include interfacial (IF) layers to study the significance of their effect. Optical properties of T2SLs are expected to have a large tunable range by controlling the thickness and material composition of the IF layers. Our model provides an efficient tool for the designs of novel photodetectors.

The Physics of Quantum Well Infrared Photodetectors

CERN Document Server

Choi, K K

1999-01-01

In the past, infrared imaging has been used exclusively for military applications. In fact, it can also be useful in a wide range of scientific and commercial applications. However, its wide spread use was impeded by the scarcity of the imaging systems and its high cost. Recently, there is an emerging infrared technology based on quantum well intersubband transition in III-V compound semiconductors. With the new technology, these impedances can be eliminated and a new era of infrared imaging is in sight. This book is designed to give a systematic description on the underlying physics of the ne

Vis-Near-Infrared Photodetectors Based on Methyl Ammonium Lead Iodide Thin Films by Pulsed Laser Deposition

Science.gov (United States)

Patel, Nagabhushan; Dias, Sandra; Krupanidhi, S. B.

2018-04-01

Organic-inorganic hybrid perovskite materials are considered as promising candidates for emerging thin-film photodetectors. In this work, we discuss the application of the CH3NH3PbI3 thin films by pulsed laser deposition for photodetection applications. With this method, we obtained good perovskite film coverage on fluorine-doped tin oxide-coated substrates and observed wel- developed grains. The films showed no sign of degradation over several months of testing. We investigated the surface morphology and surface roughness of the films by field emission scanning electron microscopy and atomic force microscopy. The optical response of the films was studied using ultraviolet-visible and photoluminescence spectroscopy. We carried out a study on the solar and infrared photodetection of CH3NH3PbI3 thin films. The values of the responsivity, sensitivity, external quantum efficiency and specific detectivity under 1 sun illumination and 0.7 V bias were 105.4 A/W, 1.9, 2.38 × 104% and 1.5 × 1012 Jones, respectively.

Transparent, broadband, flexible, and bifacial-operable photodetectors containing a large-area graphene-gold oxide heterojunction.

Science.gov (United States)

Liu, Yu-Lun; Yu, Chen-Chieh; Lin, Keng-Te; Yang, Tai-Chi; Wang, En-Yun; Chen, Hsuen-Li; Chen, Li-Chyong; Chen, Kuei-Hsien

2015-05-26

In this study, we combine graphene with gold oxide (AuOx), a transparent and high-work-function electrode material, to achieve a high-efficient, low-bias, large-area, flexible, transparent, broadband, and bifacial-operable photodetector. The photodetector operates through hot electrons being generated in the graphene and charge separation occurring at the AuOx-graphene heterojunction. The large-area graphene covering the AuOx electrode efficiently prevented reduction of its surface; it also acted as a square-centimeter-scale active area for light harvesting and photodetection. Our graphene/AuOx photodetector displays high responsivity under low-intensity light illumination, demonstrating picowatt sensitivity in the ultraviolet regime and nanowatt sensitivity in the infrared regime for optical telecommunication. In addition, this photodetector not only exhibited broadband (from UV to IR) high responsivity-3300 A W(-1) at 310 nm (UV), 58 A W(-1) at 500 nm (visible), and 9 A W(-1) at 1550 nm (IR)-but also required only a low applied bias (0.1 V). The hot-carrier-assisted photoresponse was excellent, especially in the short-wavelength regime. In addition, the graphene/AuOx photodetector exhibited great flexibility and stability. Moreover, such vertical heterojunction-based graphene/AuOx photodetectors should be compatible with other transparent optoelectronic devices, suggesting applications in flexible and wearable optoelectronic technologies.

Emerging technologies for high performance infrared detectors

OpenAIRE

Tan Chee Leong; Mohseni Hooman

2018-01-01

Infrared photodetectors (IRPDs) have become important devices in various applications such as night vision, military missile tracking, medical imaging, industry defect imaging, environmental sensing, and exoplanet exploration. Mature semiconductor technologies such as mercury cadmium telluride and III–V material-based photodetectors have been dominating the industry. However, in the last few decades, significant funding and research has been focused to improve the performance of IRPDs such as...

Modeling of the photodetector based on the multilayer graphene nanoribbons

International Nuclear Information System (INIS)

Liu, Haiyue; Niu, Yanxiong; Yin, Yiheng; Liu, Shuai

2016-01-01

Graphene nanoribbon (GNR), which has unique properties and advantages, is a crucial component of nanoelectornic devices, especially in the development of photoelectric detectors. In this work, an infrared photodetector based on the structure of stacked multiple-GNRs, which is separated by a little thick barrier layers (made of tungsten disulfide or related materials) to prevent tunneling current, is proposed and modeled. Operation of photoelectric detector is related to the electron cascaded radiative transition in the adjacent GNRs strengthened by the electrons heated due to the incident light. With a developed model, the working principle is analyzed and the relationships for the photocurrent and dark current as functions of the intensity of the incident radiation are derived. The spectral dependence of the responsivity and detectivity for graphene nanoribbons photodetector (GNRs-PT) with different Fermi energy, band gaps and numbers of GNRs layers are analyzed as well. The results demonstrate that the spectral characteristics depend on the GNRs band gap, which shows a potential on GNRs-PT application in the multi-wavelength systems. In addition, GNRs-PT has a better spectrum property and higher responsivity compared to photodetectors based on In_xGa_xAs in room temperature.

Modeling of the photodetector based on the multilayer graphene nanoribbons

Energy Technology Data Exchange (ETDEWEB)

Liu, Haiyue [Department of Instrumentation Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing, 100191 (China); Key Laboratory of Micro-nano Measurement-Manipulation and Physics Ministry of Education, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Niu, Yanxiong, E-mail: niuyx@buaa.edu.cn [Department of Instrumentation Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing, 100191 (China); Key Laboratory of Micro-nano Measurement-Manipulation and Physics Ministry of Education, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Precision Opto-mechatronics Technology Key Laboratory of Education Ministry, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Yin, Yiheng [Department of Instrumentation Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing, 100191 (China); Liu, Shuai [Department of Instrumentation Science and Opto-electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing, 100191 (China); Precision Opto-mechatronics Technology Key Laboratory of Education Ministry, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2016-07-15

Graphene nanoribbon (GNR), which has unique properties and advantages, is a crucial component of nanoelectornic devices, especially in the development of photoelectric detectors. In this work, an infrared photodetector based on the structure of stacked multiple-GNRs, which is separated by a little thick barrier layers (made of tungsten disulfide or related materials) to prevent tunneling current, is proposed and modeled. Operation of photoelectric detector is related to the electron cascaded radiative transition in the adjacent GNRs strengthened by the electrons heated due to the incident light. With a developed model, the working principle is analyzed and the relationships for the photocurrent and dark current as functions of the intensity of the incident radiation are derived. The spectral dependence of the responsivity and detectivity for graphene nanoribbons photodetector (GNRs-PT) with different Fermi energy, band gaps and numbers of GNRs layers are analyzed as well. The results demonstrate that the spectral characteristics depend on the GNRs band gap, which shows a potential on GNRs-PT application in the multi-wavelength systems. In addition, GNRs-PT has a better spectrum property and higher responsivity compared to photodetectors based on In{sub x}Ga{sub x}As in room temperature.

High-performance Schottky heterojunction photodetector with directly grown graphene nanowalls as electrodes.

Science.gov (United States)

Shen, Jun; Liu, Xiangzhi; Song, Xuefen; Li, Xinming; Wang, Jun; Zhou, Quan; Luo, Shi; Feng, Wenlin; Wei, Xingzhan; Lu, Shirong; Feng, Shuanglong; Du, Chunlei; Wang, Yuefeng; Shi, Haofei; Wei, Dapeng

2017-05-11

Schottky heterojunctions based on graphene-silicon structures are promising for high-performance photodetectors. However, existing fabrication processes adopt transferred graphene as electrodes, limiting process compatibility and generating pollution because of the metal catalyst. In this report, photodetectors are fabricated using directly grown graphene nanowalls (GNWs) as electrodes. Due to the metal-free growth process, GNWs-Si heterojunctions with an ultralow measured current noise of 3.1 fA Hz -1/2 are obtained, and the as-prepared photodetectors demonstrate specific detectivities of 5.88 × 10 13 cm Hz 1/2 W -1 and 2.27 × 10 14 cm Hz 1/2 W -1 based on the measured and calculated noise current, respectively, under ambient conditions. These are among the highest reported values for planar silicon Schottky photodetectors. In addition, an on/off ratio of 2 × 10 7 , time response of 40 μs, cut-off frequency of 8.5 kHz and responsivity of 0.52 A W -1 are simultaneously realized. The ultralow current noise is attributed to the excellent junction quality with a barrier height of 0.69 eV and an ideal factor of 1.18. Furthermore, obvious infrared photoresponse is observed in blackbody tests, and potential applications based on the photo-thermionic effect are discussed.

Hybrid Organic-Inorganic Perovskite Photodetectors.

Science.gov (United States)

Tian, Wei; Zhou, Huanping; Li, Liang

2017-11-01

Hybrid organic-inorganic perovskite materials garner enormous attention for a wide range of optoelectronic devices. Due to their attractive optical and electrical properties including high optical absorption coefficient, high carrier mobility, and long carrier diffusion length, perovskites have opened up a great opportunity for high performance photodetectors. This review aims to give a comprehensive summary of the significant results on perovskite-based photodetectors, focusing on the relationship among the perovskite structures, device configurations, and photodetecting performances. An introduction of recent progress in various perovskite structure-based photodetectors is provided. The emphasis is placed on the correlation between the perovskite structure and the device performance. Next, recent developments of bandgap-tunable perovskite and hybrid photodetectors built from perovskite heterostructures are highlighted. Then, effective approaches to enhance the stability of perovskite photodetector are presented, followed by the introduction of flexible and self-powered perovskite photodetectors. Finally, a summary of the previous results is given, and the major challenges that need to be addressed in the future are outlined. A comprehensive summary of the research status on perovskite photodetectors is hoped to push forward the development of this field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphene-based mid-infrared room-temperature pyroelectric bolometers with ultrahigh temperature coefficient of resistance.

Science.gov (United States)

Sassi, U; Parret, R; Nanot, S; Bruna, M; Borini, S; De Fazio, D; Zhao, Z; Lidorikis, E; Koppens, F H L; Ferrari, A C; Colli, A

2017-01-31

There is a growing number of applications demanding highly sensitive photodetectors in the mid-infrared. Thermal photodetectors, such as bolometers, have emerged as the technology of choice, because they do not need cooling. The performance of a bolometer is linked to its temperature coefficient of resistance (TCR, ∼2-4% K -1 for state-of-the-art materials). Graphene is ideally suited for optoelectronic applications, with a variety of reported photodetectors ranging from visible to THz frequencies. For the mid-infrared, graphene-based detectors with TCRs ∼4-11% K -1 have been demonstrated. Here we present an uncooled, mid-infrared photodetector, where the pyroelectric response of a LiNbO 3 crystal is transduced with high gain (up to 200) into resistivity modulation for graphene. This is achieved by fabricating a floating metallic structure that concentrates the pyroelectric charge on the top-gate capacitor of the graphene channel, leading to TCRs up to 900% K -1 , and the ability to resolve temperature variations down to 15 μK.

Quantum dot optoelectronic devices: lasers, photodetectors and solar cells

International Nuclear Information System (INIS)

Wu, Jiang; Chen, Siming; Seeds, Alwyn; Liu, Huiyun

2015-01-01

Nanometre-scale semiconductor devices have been envisioned as next-generation technologies with high integration and functionality. Quantum dots, or the so-called ‘artificial atoms’, exhibit unique properties due to their quantum confinement in all 3D. These unique properties have brought to light the great potential of quantum dots in optoelectronic applications. Numerous efforts worldwide have been devoted to these promising nanomaterials for next-generation optoelectronic devices, such as lasers, photodetectors, amplifiers, and solar cells, with the emphasis on improving performance and functionality. Through the development in optoelectronic devices based on quantum dots over the last two decades, quantum dot devices with exceptional performance surpassing previous devices are evidenced. This review describes recent developments in quantum dot optoelectronic devices over the last few years. The paper will highlight the major progress made in 1.3 μm quantum dot lasers, quantum dot infrared photodetectors, and quantum dot solar cells. (topical review)

Mapping human skeletal muscle perforator vessels using a quantum well infrared photodetector (QWIP) might explain the variability of NIRS and LDF measurements

International Nuclear Information System (INIS)

Binzoni, T; Leung, T; Delpy, D T; Fauci, M A; Ruefenacht, D

2004-01-01

Near-infrared spectroscopy (NIRS) and laser Doppler flowmetry (LDF) have become the techniques of choice allowing the non-invasive study of local human skeletal muscle metabolism and blood perfusion on a small tissue volume (a few cm 3 ). However, it has been shown that both NIRS and LDF measurements may show a large spatial variability depending on the position of the optodes over the investigated muscle. This variability may be due to local morphologic and/or metabolic characteristics of the muscle and makes the data interpretation and comparison difficult. In the present work, we use a third method to investigate this problem which permits fast, non-invasive mapping of the intramuscular vessel distribution in the human vastus lateralis muscle. This method uses an advanced, passive, infrared imaging sensor called a QWIP (quantum well infrared photodetector). We demonstrate, using a recovery-enhanced infrared imaging technique, that there is a significant presence of perforator vessels in the region of interest of ∼30 x 18 cm (the number of vessels being: 14, 9, 8, 33, 17 and 18 for each subject, respectively). The presence of these vessels makes the skeletal muscle highly inhomogeneous, and may explain the observed NIRS and LDF spatial variability. We conclude that accurate comparison of the metabolic activity of two different muscle regions is not possible without reliable maps of vascular 'singularities' such as the perforator vessels, and that the QWIP-based imaging system is one method to obtain this information. (note)

P3HT-graphene bilayer electrode for Schottky junction photodetectors

Science.gov (United States)

Aydın, H.; Kalkan, S. B.; Varlikli, C.; Çelebi, C.

2018-04-01

We have investigated the effect of a poly (3-hexylthiophene-2.5-diyl)(P3HT)-graphene bilayer electrode on the photoresponsivity characteristics of Si-based Schottky photodetectors. P3HT, which is known to be an electron donor and absorb light in the visible spectrum, was placed on CVD grown graphene by dip-coating method. The results of the UV-vis and Raman spectroscopy measurements have been evaluated to confirm the optical and electronic modification of graphene by the P3HT thin film. Current-voltage measurements of graphene/Si and P3HT-graphene/Si revealed rectification behavior confirming a Schottky junction formation at the graphene/Si interface. Time-resolved photocurrent spectroscopy measurements showed the devices had excellent durability and a fast response speed. We found that the maximum spectral photoresponsivity of the P3HT-graphene/Si photodetector increased more than three orders of magnitude compared to that of the bare graphene/Si photodetector. The observed increment in the photoresponsivity of the P3HT-graphene/Si samples was attributed to the charge transfer doping from P3HT to graphene within the spectral range between near-ultraviolet and near-infrared. Furthermore, the P3HT-graphene electrode was found to improve the specific detectivity and noise equivalent power of graphene/Si photodetectors. The obtained results showed that the P3HT-graphene bilayer electrodes significantly improved the photoresponsivity characteristics of our samples and thus can be used as a functional component in Si-based optoelectronic device applications.

Heterojunction photodetector based on graphene oxide sandwiched between ITO and p-Si

Science.gov (United States)

Ahmad, H.; Tajdidzadeh, M.; Thandavan, T. M. K.

2018-02-01

The drop casting method is utilized on indium tin oxide (ITO)-coated glass in order to prepare a sandwiched ITO/graphene oxide (ITO/GO) with silicon dioxide/p-type silicon (SiO2/p-Si) heterojunction photodetector. The partially sandwiched GO layer with SiO2/p-Si substrate exhibits dual characteristics as it showed good sensitivity towards the illumination of infrared (IR) laser at wavelength of 974 nm. Excellent photoconduction is also observed for current-voltage (I-V) characteristics at various laser powers. An external quantum efficiency greater than 1 for a direct current bias voltage of 0 and 3 V reveals significant photoresponsivity of the photodetector at various laser frequency modulation at 1, 5 and 9 Hz. The rise times are found to be 75, 72 and 70 μs for 1, 5 and 9 Hz while high fall times 455, 448 and 426 are measured for the respective frequency modulation. The fabricated ITO/GO-SiO2/p-Si sandwiched heterojunction photodetector can be considered as a good candidate for applications in the IR regions that do not require a high-speed response.

Printed photodetectors

International Nuclear Information System (INIS)

Pace, Giuseppina; Grimoldi, Andrea; Sampietro, Marco; Natali, Dario; Caironi, Mario

2015-01-01

Photodetectors convert light pulses into electrical signals and are fundamental building blocks for any opto-electronic system adopting light as a probe or information carrier. They have widespread technological applications, from telecommunications to sensors in industrial, medical and civil environments. Further opportunities are plastic short-range communications systems, interactive large-area surfaces and light-weight, flexible, digital imagers. These applications would greatly benefit from the cost-effective fabrication processes enabled by printing technology. While organic semiconductors are the most investigated materials for printed photodetectors, and are the main focus of the present review, there are notable examples of other inorganic or hybrid printable semiconductors for opto-electronic systems, such as quantum-dots and nanowires. Here we propose an overview on printed photodetectors, including three-terminal phototransistors. We first give a brief account of the working mechanism of these light sensitive devices, and then we review the recent progress achieved with scalable printing techniques such as screen-printing, inkjet and other non-contact technologies in the development of all-printed or hybrid systems. (paper)

Printed photodetectors

Science.gov (United States)

Pace, Giuseppina; Grimoldi, Andrea; Sampietro, Marco; Natali, Dario; Caironi, Mario

2015-10-01

Photodetectors convert light pulses into electrical signals and are fundamental building blocks for any opto-electronic system adopting light as a probe or information carrier. They have widespread technological applications, from telecommunications to sensors in industrial, medical and civil environments. Further opportunities are plastic short-range communications systems, interactive large-area surfaces and light-weight, flexible, digital imagers. These applications would greatly benefit from the cost-effective fabrication processes enabled by printing technology. While organic semiconductors are the most investigated materials for printed photodetectors, and are the main focus of the present review, there are notable examples of other inorganic or hybrid printable semiconductors for opto-electronic systems, such as quantum-dots and nanowires. Here we propose an overview on printed photodetectors, including three-terminal phototransistors. We first give a brief account of the working mechanism of these light sensitive devices, and then we review the recent progress achieved with scalable printing techniques such as screen-printing, inkjet and other non-contact technologies in the development of all-printed or hybrid systems.

Enhanced Responsivity of Photodetectors Realized via Impact Ionization

Directory of Open Access Journals (Sweden)

De-Zhen Shen

2012-01-01

Full Text Available To increase the responsivity is one of the vital issues for a photodetector. By employing ZnO as a representative material of ultraviolet photodetectors and Si as a representative material of visible photodetectors, an impact ionization process, in which additional carriers can be generated in an insulating layer at a relatively large electric field, has been employed to increase the responsivity of a semiconductor photodetector. It is found that the responsivity of the photodetectors can be enhanced by tens of times via this impact ionization process. The results reported in this paper provide a general route to enhance the responsivity of a photodetector, thus may represent a step towards high-performance photodetectors.

InN-based heterojunction photodetector with extended infrared response

KAUST Repository

Hsu, Lung-Hsing

2015-11-21

© 2015 Optical Society of America. The combination of ZnO, InN, and GaN epitaxial layers is explored to provide long wavelength photodetection capability in the GaN based materials. Growth temperature optimization was performed to obtain the best quality of InN epitaxial layer in the MOCVD system. The temperature dependent photoluminescence (PL) can provide the information about thermal quenching in the InN PL transitions and at least two nonradiative processes can be observed. X-ray diffraction and energy dispersive spectroscopy are applied to confirm the inclusion of indium and the formation of InN layer. The band alignment of such system shows a typical double heterojunction, which is preferred in optoelectronic device operation. The photodetector manufactured by this ZnO/GaN/InN layer can exhibit extended long-wavelength quantum efficiency, as high as 3.55%, and very strong photocurrent response under solar simulator illumination.

InN-based heterojunction photodetector with extended infrared response

KAUST Repository

Hsu, Lung-Hsing; Kuo, Chien-Ting; Huang, Jhih-Kai; Hsu, Shun-Chieh; Lee, Hsin-Ying; Kuo, Hao-Chung; Lee, Po-Tsung; Tsai, Yu-Lin; Hwang, Yi-Chia; Su, Chen-Feng; He, Jr-Hau; Lin, Shih-Yen; Cheng, Yuh-Jen; Lin, Chien-Chung

2015-01-01

© 2015 Optical Society of America. The combination of ZnO, InN, and GaN epitaxial layers is explored to provide long wavelength photodetection capability in the GaN based materials. Growth temperature optimization was performed to obtain the best quality of InN epitaxial layer in the MOCVD system. The temperature dependent photoluminescence (PL) can provide the information about thermal quenching in the InN PL transitions and at least two nonradiative processes can be observed. X-ray diffraction and energy dispersive spectroscopy are applied to confirm the inclusion of indium and the formation of InN layer. The band alignment of such system shows a typical double heterojunction, which is preferred in optoelectronic device operation. The photodetector manufactured by this ZnO/GaN/InN layer can exhibit extended long-wavelength quantum efficiency, as high as 3.55%, and very strong photocurrent response under solar simulator illumination.

Three-Dimensional Integration of Black Phosphorus Photodetector with Silicon Photonics and Nanoplasmonics.

Science.gov (United States)

Chen, Che; Youngblood, Nathan; Peng, Ruoming; Yoo, Daehan; Mohr, Daniel A; Johnson, Timothy W; Oh, Sang-Hyun; Li, Mo

2017-02-08

We demonstrate the integration of a black phosphorus photodetector in a hybrid, three-dimensional architecture of silicon photonics and metallic nanoplasmonics structures. This integration approach combines the advantages of the low propagation loss of silicon waveguides, high-field confinement of a plasmonic nanogap, and the narrow bandgap of black phosphorus to achieve high responsivity for detection of telecom-band, near-infrared light. Benefiting from an ultrashort channel (∼60 nm) and near-field enhancement enabled by the nanogap structure, the photodetector shows an intrinsic responsivity as high as 10 A/W afforded by internal gain mechanisms, and a 3 dB roll-off frequency of 150 MHz. This device demonstrates a promising approach for on-chip integration of three distinctive photonic systems, which, as a generic platform, may lead to future nanophotonic applications for biosensing, nonlinear optics, and optical signal processing.

High Detectivity Graphene-Silicon Heterojunction Photodetector.

Science.gov (United States)

Li, Xinming; Zhu, Miao; Du, Mingde; Lv, Zheng; Zhang, Li; Li, Yuanchang; Yang, Yao; Yang, Tingting; Li, Xiao; Wang, Kunlin; Zhu, Hongwei; Fang, Ying

2016-02-03

A graphene/n-type silicon (n-Si) heterojunction has been demonstrated to exhibit strong rectifying behavior and high photoresponsivity, which can be utilized for the development of high-performance photodetectors. However, graphene/n-Si heterojunction photodetectors reported previously suffer from relatively low specific detectivity due to large dark current. Here, by introducing a thin interfacial oxide layer, the dark current of graphene/n-Si heterojunction has been reduced by two orders of magnitude at zero bias. At room temperature, the graphene/n-Si photodetector with interfacial oxide exhibits a specific detectivity up to 5.77 × 10(13) cm Hz(1/2) W(-1) at the peak wavelength of 890 nm in vacuum, which is highest reported detectivity at room temperature for planar graphene/Si heterojunction photodetectors. In addition, the improved graphene/n-Si heterojunction photodetectors possess high responsivity of 0.73 A W(-1) and high photo-to-dark current ratio of ≈10(7) . The current noise spectral density of the graphene/n-Si photodetector has been characterized under ambient and vacuum conditions, which shows that the dark current can be further suppressed in vacuum. These results demonstrate that graphene/Si heterojunction with interfacial oxide is promising for the development of high detectivity photodetectors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thallium bromide photodetectors for scintillation detection

CERN Document Server

Hitomi, K; Shoji, T; Hiratate, Y; Ishibashi, H; Ishii, M

2000-01-01

A wide bandgap compound semiconductor, TlBr, has been investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TMZ method using materials purified by many pass zone refining. The performance of the photodetectors has been evaluated by measuring their leakage current, quantum efficiency, spatial uniformity, direct X-ray detection and scintillation detection characteristics. The photodetectors have shown high quantum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection characteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a sup 1 sup 0 sup 9 Cd radioactive source have been obtained. Detection of blue scintillation from GSO and LSO scintillators irradiated with a sup 2 sup 2 Na radioactive source has been done successfully by using the photodetectors at room temperature. A clear full-energy pea...

Bolometric-Effect-Based Wavelength-Selective Photodetectors Using Sorted Single Chirality Carbon Nanotubes

Science.gov (United States)

Zhang, Suoming; Cai, Le; Wang, Tongyu; Shi, Rongmei; Miao, Jinshui; Wei, Li; Chen, Yuan; Sepúlveda, Nelson; Wang, Chuan

2015-01-01

This paper exploits the chirality-dependent optical properties of single-wall carbon nanotubes for applications in wavelength-selective photodetectors. We demonstrate that thin-film transistors made with networks of carbon nanotubes work effectively as light sensors under laser illumination. Such photoresponse was attributed to photothermal effect instead of photogenerated carriers and the conclusion is further supported by temperature measurements. Additionally, by using different types of carbon nanotubes, including a single chirality (9,8) nanotube, the devices exhibit wavelength-selective response, which coincides well with the absorption spectra of the corresponding carbon nanotubes. This is one of the first reports of controllable and wavelength-selective bolometric photoresponse in macroscale assemblies of chirality-sorted carbon nanotubes. The results presented here provide a viable route for achieving bolometric-effect-based photodetectors with programmable response spanning from visible to near-infrared by using carbon nanotubes with pre-selected chiralities. PMID:26643777

Photodetector of ultra-violet radiation

International Nuclear Information System (INIS)

Dorogan, V.; Vieru, T.; Coseac, V.; Chirita, F.

1999-01-01

The invention relates to photodetectors on the semiconductors base, in particular, to photodetectors of ultra-violet radiation and can be used in the optoelectronics systems for determining the intensity and dose of ultraviolet radiation emitted by the Sun and other sources. In the structure of the photodetector of ultraviolet radiation with a superficial potential barrier formed of semiconductors A 3 B 5 with the prohibited power width Eg 1 , solid solutions thereof with the prohibited power width Eg 2 and SnO 2 or ITO, in the semiconductors A 3 B 5 at a surface distance less than the absorption length of the visible radiation it is formed an isotype heterojunction between the semiconductors A 3 B 5 and solid solutions thereof with the prohibited power width Eg 2 > Eg 1 . The technical result consists in manufacturing of a photodetector sensitive solely to the ultraviolet radiation

Photodetector based on carbon nanotubes

Science.gov (United States)

Pavlov, A.; Kitsyuk, E.; Ryazanov, R.; Timoshenkov, V.; Adamov, Y.

2015-09-01

Photodetector based on carbon nanotubes (CNT) was investigated. Sensors were done on quartz and silicon susbtrate. Samples of photodetectors sensors were produced by planar technology. This technology included deposition of first metal layer (Al), lithography for pads formation, etching, and formation of local catalyst area by inverse lithography. Vertically-aligned multi-wall carbon nanotubes were directly synthesized on substrate by PECVD method. I-V analysis and spectrum sensitivity of photodetector were investigated for 0.4 μm - 1.2 μm wavelength. Resistivity of CNT layers over temperature was detected in the range of -20°C to 100°C.

Self-Powered, High-Speed and Visible-Near Infrared Response of MoO(3-x)/n-Si Heterojunction Photodetector with Enhanced Performance by Interfacial Engineering.

Science.gov (United States)

Zhao, Chuanxi; Liang, Zhimin; Su, Mingze; Liu, Pengyi; Mai, Wenjie; Xie, Weiguang

2015-11-25

Photodetectors with a wide spectrum response are important components for sensing, imaging, and other optoelectronic applications. A molybdenum oxide (MoO(3-x))/Si heterojunction has been applied as solar cells with great success, but its potential in photodetectors has not been explored yet. Herein, a self-powered, high-speed heterojunction photodetector fabricated by coating an n-type Si hierarchical structure with an ultrathin hole-selective layer of molybdenum oxide (MoO(3-x)) is first investigated. Excellent and stable photoresponse performance is obtained by using a methyl group passivated interface. The heterojunction photodetector demonstrated high sensitivity to a wide spectrum from 300 to 1100 nm. The self-powered photodetector shows a high detectivity of (∼6.29 × 10(12) cmHz(1/2) W(-1)) and fast response time (1.0 μs). The excellent photodetecting performance is attributed to the enhanced interfacial barrier height and three-dimensional geometry of Si nanostructures, which is beneficial for efficient photocarrier collection and transportation. Finally, our devices show excellent long-term stability in air for 6 months with negligible performance degradation. The thermal evaporation method for large-scale fabrication of MoO(3-x)/n-Si photodetectors makes it suitable for self-powered, multispectral, and high-speed response photodetecting applications.

Graphene quantum interference photodetector

Directory of Open Access Journals (Sweden)

Mahbub Alam

2015-03-01

Full Text Available In this work, a graphene quantum interference (QI photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI, which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector, low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

Photodetectors based on junctions of two-dimensional transition metal dichalcogenides

International Nuclear Information System (INIS)

Wei Xia; Yan Fa-Guang; Shen Chao; Lv Quan-Shan; Wang Kai-You

2017-01-01

Transition metal dichalcogenides (TMDCs) have gained considerable attention because of their novel properties and great potential applications. The flakes of TMDCs not only have great light absorption from visible to near infrared, but also can be stacked together regardless of lattice mismatch like other two-dimensional (2D) materials. Along with the studies on intrinsic properties of TMDCs, the junctions based on TMDCs become more and more important in applications of photodetection. The junctions have shown many exciting possibilities to fully combine the advantages of TMDCs, other 2D materials, conventional and organic semiconductors together. Early studies have greatly enriched the application of TMDCs in photodetection. In this review, we investigate the efforts in photodetectors based on the junctions of TMDCs and analyze the properties of those photodetectors. Homojunctions based on TMDCs can be made by surface chemical doping, elemental doping and electrostatic gating. Heterojunction formed between TMDCs/2D materials, TMDCs/conventional semiconductors and TMDCs/organic semiconductor also deserve more attentions. We also compare the advantages and disadvantages of different junctions, and then give the prospects for the development of junctions based on TMDCs. (topical reviews)

Emerging terahertz photodetectors based on two-dimensional materials

Science.gov (United States)

Yang, Jie; Qin, Hua; Zhang, Kai

2018-01-01

Inspired by the innovations in photonics and nanotechnology, the remarkable properties of two-dimensional (2D) materials have renewed interest for the development of terahertz (THz) photodetectors. The versatility of these materials enables ultrafast and ultrasensitive photodetection of THz radiation at room temperature. The atomically thin characteristic together with van der Waals interactions among the layers make it easy to scaling down and integrate with other 2D materials based devices, as well as silicon chips. Efforts have increased fast in the past decade in developing proof-of-concept and the further prospective THz photodetectors based on 2D materials. Here, the recent progress on the exploring of THz photodetectors based on 2D materials is reviewed. We summarized the THz photodetectors under different physical mechanism and introduced the state-of-the-art THz photodetectors based on various promising 2D materials, such as graphene, transition metal dichalcogenides (TMDCs), black phosphorus (BP) and topological insulators (TIs). A brief discussion on the remaining challenges and a perspective of the 2D materials based THz photodetectors are also given.

Characterization and Analysis of a Multicolor Quantum Well Infrared Photodetector

National Research Council Canada - National Science Library

Hanson, Nathan A

2006-01-01

...), mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR). Through photocurrent spectroscopy and performance analysis, this prototype detector can be classified and prepared for possible future use within the U.S. Armed Forces...

Multi-terminal Two-color ZnCdSe/ZnCdMgSe Based Quantum-well Infrared Photodetector

Science.gov (United States)

Kaya, Yasin; Ravikumar, Arvind; Chen, Guopeng; Tamargo, Maria C.; Shen, Aidong; Gmachl, Claire

Target recognition and identification applications benefits from two-color infrared (IR) detectors in the mid and long-wavelength IR regions. Currently, InGaAs/AlGaAs and GaAs/AlGaAs multiple quantum wells (QWs) grown on GaAs substrate are the most commonly used two-color QW IR photodetectors (QWIPs). However, the lattice-mismatch and the buildup of strain limit the number of QWs that can be grown, in turn increasing the dark current noise, and limiting the device detectivity.In this work, we report on two-color QWIPs based on the large conduction band offset (~1.12ev) ZnCdSe/ZnCdMgSe material system lattice matched to InP. QWIPs were designed based on a bound to quasi-bound transition, centered at 4 μm and 7 μm and each QW is repeated 50 times to eliminate the high dark current and a contact layer is inserted between the two stacks of QWs for independent electrical contacts. Wafers are processed into two step rectangular mesas by lithography and wet etching. Experiments showed absorption spectra centered at 4.9 μm and 7.6 μm at 80 K and the full width at half maximums were Δλ / λ = 21 % and Δλ / λ = 23 % , respectively. Current work studies the Johnson and the background noise limited detectivities of these QWIPs. Current address: School of Earth, Energy and Environmental Sciences, Stanford, CA 94305, USA.

Highly polarization sensitive photodetectors based on quasi-1D titanium trisulfide (TiS3)

Science.gov (United States)

Liu, Sijie; Xiao, Wenbo; Zhong, Mianzeng; Pan, Longfei; Wang, Xiaoting; Deng, Hui-Xiong; Liu, Jian; Li, Jingbo; Wei, Zhongming

2018-05-01

Photodetectors with high polarization sensitivity are in great demand in advanced optical communication. Here, we demonstrate that photodetectors based on titanium trisulfide (TiS3) are extremely sensitive to polarized light (from visible to the infrared), due to its reduced in-plane structural symmetry. By density functional theory calculation, TiS3 has a direct bandgap of 1.13 eV. The highest photoresponsivity reaches 2500 A W-1. What is more, in-plane optical selection caused by strong anisotropy leads to the photoresponsivity ratio for different directions of polarization that can reach 4:1. The angle-dependent photocurrents of TiS3 clearly display strong linear dichroism. Moreover, the Raman peak at 370 cm-1 is also very sensitive to the polarization direction. The theoretical optical absorption of TiS3 is calculated by using the HSE06 hybrid functional method, in qualitative agreement with the observed experimental photoresponsivity.

High-speed photodetectors in optical communication system

Science.gov (United States)

Zhao, Zeping; Liu, Jianguo; Liu, Yu; Zhu, Ninghua

2017-12-01

This paper presents a review and discussion for high-speed photodetectors and their applications on optical communications and microwave photonics. A detailed and comprehensive demonstration of high-speed photodetectors from development history, research hotspots to packaging technologies is provided to the best of our knowledge. A few typical applications based on photodetectors are also illustrated, such as free-space optical communications, radio over fiber and millimeter terahertz signal generation systems. Project supported by the Preeminence Youth Fund of China (No. 61625504).

Digital Alloy Absorber for Photodetectors

Science.gov (United States)

Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

2016-01-01

In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

Leaky electronic states for photovoltaic photodetectors based on asymmetric superlattices

Science.gov (United States)

Penello, Germano Maioli; Pereira, Pedro Henrique; Pires, Mauricio Pamplona; Sivco, Deborah; Gmachl, Claire; Souza, Patricia Lustoza

2018-01-01

The concept of leaky electronic states in the continuum is used to achieve room temperature operation of photovoltaic superlattice infrared photodetectors. A structural asymmetric InGaAs/InAlAs potential profile is designed to create states in the continuum with the preferential direction for electron extraction and, consequently, to obtain photovoltaic operation at room temperature. Due to the photovoltaic operation and virtual increase in the bandoffset, the device presents both low dark current and low noise. The Johnson noise limited specific detectivity reaches values as high as 1.4 × 1011 Jones at 80 K. At 300 K, the detectivity obtained is 7.0 × 105 Jones.

Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

Science.gov (United States)

Jhabvala, Murzy; Jhabvala, Christine A.; Ewin, Audrey J.; Hess, Larry A.; Hartmann, Thomas M.; La, Anh T.

2012-01-01

A paper describes the Thermal Infrared Sensor (TIRS), a QWIP-based instrument intended to supplement the Operational Land Imager (OLI) for the Landsat Data Continuity Mission (LDCM). The TIRS instrument is a far-infrared imager operating in the pushbroom mode with two IR channels: 10.8 and 12 microns. The focal plane will contain three 640x512 QWIP arrays mounted on a silicon substrate. The silicon substrate is a custom-fabricated carrier board with a single layer of aluminum interconnects. The general fabrication process starts with a 4-in. (approx.10-cm) diameter silicon wafer. The wafer is oxidized, a single substrate contact is etched, and aluminum is deposited, patterned, and alloyed. This technology development is aimed at incorporating three large-format infrared detecting arrays based on GaAs QWIP technology onto a common focal plane with precision alignment of all three arrays. This focal plane must survive the rigors of flight qualification and operate at a temperature of 43 K (-230 C) for five years while orbiting the Earth. The challenges presented include ensuring thermal compatibility among all the components, designing and building a compact, somewhat modular system and ensuring alignment to very tight levels. The multi-array focal plane integrated onto a single silicon substrate is a new application of both QWIP array development and silicon wafer scale integration. The Invar-based assembly has been tested to ensure thermal reliability.

Vertical Ge photodetector base on InP taper waveguide

Science.gov (United States)

Amiri, Iraj Sadegh; Ariannejad, M. M.; Azzuhri, S. R. B.; Anwar, T.; Kouhdaragh, V.; Yupapin, P.

2018-06-01

In this work, simulation is conducted to investigate Ge photodetectors monolithically integrated on Si chip. The performance of vertical Germanium photodetector with FDTD Solutions (optical simulation) and electrical simulation has been studied. Selective heteroepitaxy of Ge is functioned in the monolithic integration of Ge photodetectors. The potential of CMOS-compatible monolithic integration of Ge as photodetector is investigated and the performance optimization is presented. Additionally, the investigation is extended to electrical part, particularly in the conversion efficiency as well as operation under low supplied voltage condition.

Plasmonic-Resonant Bowtie Antenna for Carbon Nanotube Photodetectors

Directory of Open Access Journals (Sweden)

Hongzhi Chen

2012-01-01

Full Text Available The design of bowtie antennas for carbon nanotube (CNT photodetectors has been investigated. CNT photodetectors have shown outstanding performance by using CNT as sensing element. However, detection wavelength is much larger than the diameter of the CNT, resulting in small fill factor. Bowtie antenna can confine light into a subwavelength volume based on plasmonic resonance, thus integrating a bowtie antenna to CNT photodetectors can highly improve photoresponse of the detectors. The electric field enhancement of bowtie antennas was calculated using the device geometry by considering fabrication difficulties and photodetector structure. It is shown that the electric field intensity enhancement increased exponentially with distance reduction between the CNT photodetector to the antenna. A redshift of the peak resonance wavelength is predicted due to the increase of tip angles of the bowtie antennas. Experimental results showed that photocurrent enhancement agreed well with theoretical calculations. Bowtie antennas may find wide applications in nanoscale photonic sensors.

A MoTe2-based light-emitting diode and photodetector for silicon photonic integrated circuits.

Science.gov (United States)

Bie, Ya-Qing; Grosso, Gabriele; Heuck, Mikkel; Furchi, Marco M; Cao, Yuan; Zheng, Jiabao; Bunandar, Darius; Navarro-Moratalla, Efren; Zhou, Lin; Efetov, Dmitri K; Taniguchi, Takashi; Watanabe, Kenji; Kong, Jing; Englund, Dirk; Jarillo-Herrero, Pablo

2017-12-01

One of the current challenges in photonics is developing high-speed, power-efficient, chip-integrated optical communications devices to address the interconnects bottleneck in high-speed computing systems. Silicon photonics has emerged as a leading architecture, in part because of the promise that many components, such as waveguides, couplers, interferometers and modulators, could be directly integrated on silicon-based processors. However, light sources and photodetectors present ongoing challenges. Common approaches for light sources include one or few off-chip or wafer-bonded lasers based on III-V materials, but recent system architecture studies show advantages for the use of many directly modulated light sources positioned at the transmitter location. The most advanced photodetectors in the silicon photonic process are based on germanium, but this requires additional germanium growth, which increases the system cost. The emerging two-dimensional transition-metal dichalcogenides (TMDs) offer a path for optical interconnect components that can be integrated with silicon photonics and complementary metal-oxide-semiconductors (CMOS) processing by back-end-of-the-line steps. Here, we demonstrate a silicon waveguide-integrated light source and photodetector based on a p-n junction of bilayer MoTe 2 , a TMD semiconductor with an infrared bandgap. This state-of-the-art fabrication technology provides new opportunities for integrated optoelectronic systems.

A MoTe2-based light-emitting diode and photodetector for silicon photonic integrated circuits

Science.gov (United States)

Bie, Ya-Qing; Grosso, Gabriele; Heuck, Mikkel; Furchi, Marco M.; Cao, Yuan; Zheng, Jiabao; Bunandar, Darius; Navarro-Moratalla, Efren; Zhou, Lin; Efetov, Dmitri K.; Taniguchi, Takashi; Watanabe, Kenji; Kong, Jing; Englund, Dirk; Jarillo-Herrero, Pablo

2017-12-01

One of the current challenges in photonics is developing high-speed, power-efficient, chip-integrated optical communications devices to address the interconnects bottleneck in high-speed computing systems. Silicon photonics has emerged as a leading architecture, in part because of the promise that many components, such as waveguides, couplers, interferometers and modulators, could be directly integrated on silicon-based processors. However, light sources and photodetectors present ongoing challenges. Common approaches for light sources include one or few off-chip or wafer-bonded lasers based on III-V materials, but recent system architecture studies show advantages for the use of many directly modulated light sources positioned at the transmitter location. The most advanced photodetectors in the silicon photonic process are based on germanium, but this requires additional germanium growth, which increases the system cost. The emerging two-dimensional transition-metal dichalcogenides (TMDs) offer a path for optical interconnect components that can be integrated with silicon photonics and complementary metal-oxide-semiconductors (CMOS) processing by back-end-of-the-line steps. Here, we demonstrate a silicon waveguide-integrated light source and photodetector based on a p-n junction of bilayer MoTe2, a TMD semiconductor with an infrared bandgap. This state-of-the-art fabrication technology provides new opportunities for integrated optoelectronic systems.

Long-wavelength germanium photodetectors by ion implantation

International Nuclear Information System (INIS)

Wu, I.C.; Beeman, J.W.; Luke, P.N.; Hansen, W.L.; Haller, E.E.

1990-11-01

Extrinsic far-infrared photoconductivity in thin high-purity germanium wafers implanted with multiple-energy boron ions has been investigated. Initial results from Fourier transform spectrometer(FTS) measurements have demonstrated that photodetectors fabricated from this material have an extended long-wavelength threshold near 192μm. Due to the high-purity substrate, the ability to block the hopping conduction in the implanted IR-active layer yields dark currents of less than 100 electrons/sec at temperatures below 1.3 K under an operating bias of up to 70 mV. Optimum peak responsivity and noise equivalent power (NEP) for these sensitive detectors are 0.9 A/W and 5 x 10 -16 W/Hz 1/2 at 99 μm, respectively. The dependence of the performance of devices on the residual donor concentration in the implanted layer will be discussed. 12 refs., 4 figs

Advances in semiconductor photodetectors for scintillators

International Nuclear Information System (INIS)

Farrell, R.; Olschner, F.; Shah, K.; Squillante, M.R.

1997-01-01

Semiconductors photodetectors have long seemed an attractive alternative for scintillation detection, but only recently have semiconductor photodiodes been proven suitable for some room temperature applications. There are many applications, however for which the performance of standard silicon p-i-n photodiodes is not satisfactory. This article reviews recent progress in two different families of novel semiconductor photodetectors: (1) wide bandgap compound semiconductors and (2) silicon photodetectors with enhanced signal-to-noise ratio. The compounds discussed and compared in this paper are HgI 2 , PbI 2 , InI, TlBr, TlBr 1-x I x and HgBr 1-x I x . The paper will also examine unity gain silicon drift diodes and avalanche photodiodes with maximum room temperature gain greater than 10000. (orig.)

A Photodetector Based on p-Si/n-ZnO Nanotube Heterojunctions with High Ultraviolet Responsivity

KAUST Repository

Flemban, Tahani H.

2017-09-19

Enhanced ultraviolet (UV) photodetectors (PDs) with high responsivity comparable to that of visible and infrared photodetectors are needed for commercial applications. n-Type ZnO nanotubes (NTs) with high-quality optical, structural, and electrical properties on a p-type Si(100) substrate are successfully fabricated by pulsed laser deposition (PLD) to produce a UV PD with high responsivity, for the first time. We measure the current–voltage characteristics of the device under dark and illuminated conditions and demonstrated the high stability and responsivity (that reaches ∼101.2 A W–1) of the fabricated UV PD. Time-resolved spectroscopy is employed to identify exciton confinement, indicating that the high PD performance is due to optical confinement, the high surface-to-volume ratio, the high structural quality of the NTs, and the high photoinduced carrier density. The superior detectivity and responsivity of our NT-based PD clearly demonstrate that fabrication of high-performance UV detection devices for commercial applications is possible.

Enhanced Graphene Photodetector with Fractal Metasurface

DEFF Research Database (Denmark)

Fan, Jieran; Wang, Di; DeVault, Clayton

2016-01-01

We designed and fabricated a broadband, polarization-independent photodetector by integrating graphene with a fractal Cayley tree metasurface. Our measurements show an almost uniform, tenfold enhancement in photocurrent generation due to the fractal metasurface structure.......We designed and fabricated a broadband, polarization-independent photodetector by integrating graphene with a fractal Cayley tree metasurface. Our measurements show an almost uniform, tenfold enhancement in photocurrent generation due to the fractal metasurface structure....

Optimization of a solar-blind and middle infrared two-colour photodetector using GaN-based bulk material and quantum wells

International Nuclear Information System (INIS)

Long-Bin, Cen; Bo, Shen; Zhi-Xin, Qin; Guo-Yi, Zhang

2009-01-01

This paper calculates the wavelengths of the interband transitions as a function of the Al mole fraction of A1xGa 1–x N bulk material. It is finds that when the Al mole fraction is between 0.456 and 0.639, the wavelengths correspond to the solar-blind (250 nm to 280 nm). The influence of the structure parameters of A1yGa 1–y N/GaN quantum wells on the wavelength and absorption coefficient of intersubband transitions has been investigated by solving the Schrödinger and Poisson equations self-consistently. The A1 mole fraction of the A1yGa 1–y N barrier changes from 0.30 to 0.46, meanwhile the width of the well changes from 2.9 nm to 2.2 nm, for maximal intersubband absorption in the window of the air (3 μm < λ < 5 μm). The absorption coefficient of the intersubband transition between the ground state and the first excited state decreases with the increase of the wavelength. The results are finally used to discuss the prospects of GaN-based bulk material and quantum wells for a solar-blind and middle infrared two-colour photodetector. (classical areas of phenomenology)

Investigation of the optical properties of InAs/InGaAs/GaAs quantum dot in quantum well multilayer structures for infrared photodetectors

KAUST Repository

Ivanov, Ts

2012-03-29

A detailed study of InAs/InGaAs quantum dots in quantum well (DWELL) structures grown on GaAs substrates for infrared photodetectors was performed using surface photovoltage (SPV) spectroscopy. Three types of samples were investigated: as-grown, and annealed with dielectric coating SiO 2 or SiN. The annealing resulted in intermixing of the material components. The amplitude and phase SPV spectra were measured at room temperature under various experimental conditions. The comparison of the SPV with the photoluminescence (PL) spectra allows one to conclude that the spectral features are due to optical transitions in the DWELL structure. The blueshift observed of these features in the intermixed samples implies that the energy levels responsible for the transitions change correspondingly due to the intermixing process. The interface band-bending in the samples and the mechanisms of the carrier dynamics were determined by a comparative analysis of the SPV amplitude and phase spectra, using our vector model for representation of the SPV signal. © Published under licence by IOP Publishing Ltd.

Investigation of the optical properties of InAs/InGaAs/GaAs quantum dot in quantum well multilayer structures for infrared photodetectors

KAUST Repository

Ivanov, Ts; Borissov, K.; David, J P R; Donchev, V.; Germanova, K.; Hongpinyo, V.; Ooi, Boon S.; Tellaleva, Ts; Vines, P.

2012-01-01

A detailed study of InAs/InGaAs quantum dots in quantum well (DWELL) structures grown on GaAs substrates for infrared photodetectors was performed using surface photovoltage (SPV) spectroscopy. Three types of samples were investigated: as-grown, and annealed with dielectric coating SiO 2 or SiN. The annealing resulted in intermixing of the material components. The amplitude and phase SPV spectra were measured at room temperature under various experimental conditions. The comparison of the SPV with the photoluminescence (PL) spectra allows one to conclude that the spectral features are due to optical transitions in the DWELL structure. The blueshift observed of these features in the intermixed samples implies that the energy levels responsible for the transitions change correspondingly due to the intermixing process. The interface band-bending in the samples and the mechanisms of the carrier dynamics were determined by a comparative analysis of the SPV amplitude and phase spectra, using our vector model for representation of the SPV signal. © Published under licence by IOP Publishing Ltd.

High-performance polymer photovoltaic cells and photodetectors

Science.gov (United States)

Yu, Gang; Srdanov, Gordana; Wang, Hailiang; Cao, Yong; Heeger, Alan J.

2001-02-01

Polymer photovoltaic cells and photodetectors have passed their infancy and become mature technologies. The energy conversion efficiency of polymer photovoltaic cells have been improved to over 4.1% (500 nm, 10 mW/cm2). Such high efficiency polymer photovoltaic cells are promising for many applications including e-papers, e-books and smart- windows. The development of polymer photodetectors is even faster. The performance parameters have been improved to the level meeting all specifications for practical applications. The polymer photodetectors are of high photosensitivity (approximately 0.2 - 0.3 A/Watt in visible and UV), low dark current (0.1 - 1 nA/cm2), large dynamic range (> 8 orders of magnitude), linear intensity dependence, low noise level and fast response time (to nanosecond time domain). These devices show long shelf and operation lives. The advantages of low manufacturing cost, large detection area, and easy hybridization and integration with other electronic or optical components make the polymer photodetectors promising for a variety of applications including chemical/biomedical analysis, full-color digital image sensing and high energy radiation detection.

Reduced graphene oxide mid-infrared photodetector at 300 K

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Gustavo E.; Kim, Jin Ho; Oller, Declan; Xu, Jimmy [School of Engineering, Brown University, Box D, Providence, Rhode Island 02912 (United States)

2015-09-14

We report on uncooled mid-infrared photovoltaic responses at 300 K arising in heterojunctions of reduced graphene oxide with p-Si. Two major photoresponse spectral peaks are observed, one in the near infrared starting at 1.1 μm corresponding to electron-hole pair generation in the Si substrate, and another at wavelengths below 2.5 μm, arising from properties of the reduced graphene oxide-Si heterojunction. Our analysis of the current-voltage characteristics at various temperatures suggests that the two materials form a type-II (broken-gap) heterojunction, with a characteristic transition between direct tunneling to field emission, to over-the-barrier excitation with increasing reverse voltage. Illumination was found to affect the onset of the transition between direct tunneling and field-emission, suggesting that the mid infrared response results from the excitation of minority carriers (electrons) from the Si and their collection in the reduced graphene oxide contact. The photoresponse near 1.1 μm showed a time constant at least five times faster than the one at 2.5 μm, which points to surface defects as well as high series resistance and capacitance as potentially limiting factors in this mode of operation. With proper device engineering considerations, these devices could be promising as a graphene-based platform for infrared sensing.

Quantum Well Infrared Photodetectors: Device Physics and Light Coupling

Science.gov (United States)

Bandara, S. V.; Gunapala, S. D.; Liu, J. K.; Mumolo, J.; Luong, E.; Hong, W.; Sengupta, D. K.

1997-01-01

It is customary to make infrared (IR) detectors in the long wavelength range by utilizing the interband transition which promotes an electron across the band gap (Eg) from the valence band to the conduction.

Infrared photodetectors based on reduced graphene oxide nanoparticles and graphene oxide

Science.gov (United States)

Ahmad, H.; Tajdidzadeh, M.; Thambiratnam, K.; Yasin, M.

2018-06-01

Two photodiode (PD) designs incorporating graphene oxide (GO) and reduced graphene oxide (rGO) are proposed and fabricated. Both PDs have 50 mm thick silver electrodes deposited on the active area, and another electrode consisting of either GO or rGO nanoparticles (NPs). The GO and rGO NPs are deposited onto the p-type silicon substrate by the drop casting method. Both fabricated PDs show good sensitivity and quick responses under 974 nm laser illumination at 150 mW. The photoresponsivity values and external quantum efficiency of both photodetectors are measured to be approximately 800 µAw‑1 and 0.12% for the GO based PD and 1.6 m Aw‑1 and 0.20% for the rGO based PD. Both PDs also have response and recovery times of 114 µs and 276 µs as well as 11 µs and 678 µs for the GO and rGO based PDs respectively. The proposed PDs would have significant applications in many optoelectronic devices as well as nanoelectronics.

Low Voltage Low Light Imager and Photodetector

Science.gov (United States)

Nikzad, Shouleh (Inventor); Martin, Chris (Inventor); Hoenk, Michael E. (Inventor)

2013-01-01

Highly efficient, low energy, low light level imagers and photodetectors are provided. In particular, a novel class of Della-Doped Electron Bombarded Array (DDEBA) photodetectors that will reduce the size, mass, power, complexity, and cost of conventional imaging systems while improving performance by using a thinned imager that is capable of detecting low-energy electrons, has high gain, and is of low noise.

Microchannel plate photodetectors

International Nuclear Information System (INIS)

Majka, R.

1977-01-01

A review is given the status of development work on photodetectors using microchannel plates (MCP) as the electron gain element. Projections are made and opinions are presented on what might be available in the next few years. Several uses for these devices at ISABELLE are mentioned

Fabrication of InP-pentacene inorganic-organic hybrid heterojunction using MOCVD grown InP for photodetector application

Science.gov (United States)

Sarkar, Kalyan Jyoti; Pal, B.; Banerji, P.

2018-04-01

We fabricated inorganic-organic hybrid heterojunction between indium phosphide (InP) and pentacene for photodetector application. InP layer was grown on n-Si substrate by atmospheric pressure metal organic chemical vapour deposition (MOCVD) technique. Morphological properties of InP and pentacene thin film were characterized by atomic force microscopy (AFM). Current-voltage characteristics were investigated in dark and under illumination condition at room temperature. During illumination, different wavelengths of visible and infrared light source were employed to perform the electrical measurement. Enhancement of photocurrent was observed with decreasing in wavelength of incident photo radiation. Ideality factor was found to be 1.92. High rectification ratio of 225 was found at ± 3 V in presence of infrared light source. This study provides new insights of inorganic-organic hybrid heterojunction for broadband photoresponse in visible to near infrared (IR) region under low reverse bias condition.

Photodetector Characteristics in Visible Light Communication

KAUST Repository

Ho, Kang-Ting

2016-04-01

Typically, in the semiconductor industry pn heterojunctions have been used as either light-emitting diodes (LED) or photodiodes by applying forward current bias or reverse voltage bias, respectively. However, since both devices use the same structure, the light emitting and detecting properties could be combine in one single device, namely LED-based photodetector. Therefore, by integrating LED-based photodetectors as either transmitter or receiver, optical wireless communication could be easily implemented for bidirectional visible light communication networks at low-cost. Therefore, this dissertation focus on the investigation of the photodetection characteristics of InGaN LED-based photodetectors for visible light communication in the blue region. In this regard, we obtain external quantum efficiency of 10 % and photoresponse rise time of 71 μs at 405-nm illumination, revealing high-performance photodetection characteristics. Furthermore, we use orthogonal frequency division multiplexing quadrature amplitude modulation codification scheme to enlarge the operational bandwidth. Consequently, the transmission rate of the communication is efficiently enhanced up to 420 Mbit/s in visible light communication.

Latest developments in GaN-based quantum devices for infrared optoelectronics

OpenAIRE

Monroy, Eva; Guillot, Fabien; Leconte, Sylvain; Nevou, Laurent; Doyennette, Laeticia; Tchernycheva, Maria; Julien, François H.; Baumann, Esther; Giorgetta, Fabrizio R.; Hofstetter, Daniel

2011-01-01

In this work, we summarize the latest progress in intersubband devices based on GaN/AlN nanostructures for operation in the near-infrared. We first discuss the growth and characterization of ultra-thin GaN/AlN quantum well and quantum dot superlattices by plasma-assisted molecular-beam epitaxy. Then, we present the performance of nitride-based infrared photodetectors and electro-optical modulators operating at 1.55 μm. Finally, we discuss the progress towards intersubband light emitters, incl...

Photodetectors for weak-signal detection fabricated from ZnO:(Li,N) films

Energy Technology Data Exchange (ETDEWEB)

He, G.H. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, H. [Key Laboratory of Semiconductors and Applications of Fujian Province, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen 361005 (China); Shen, H. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences Changchun 130033 (China); Lu, Y.J. [Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Wang, H.Q.; Zheng, J.C. [Key Laboratory of Semiconductors and Applications of Fujian Province, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen 361005 (China); Li, B.H. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences Changchun 130033 (China); Shan, C.X., E-mail: shancx@ciomp.ac.cn [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences Changchun 130033 (China); Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Shen, D.Z. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences Changchun 130033 (China)

2017-08-01

Highlights: • ZnO films with carrier concentration as low as 5.0 × 10{sup 13} cm{sup −3} have been prepared via a lithium and nitrogen codoping method. • Ultraviolet photodetector that can detect weak signal with power density as low as 20 nw/cm{sup 2} have been fabricated from the ZnO:(Li,N) films. • The detectivity and noise equivalent power of the photodetector can reach 3.60 × 10{sup 15} cmHz{sup 1/2}/W and 6.67 × 10{sup −18} W{sup −1}, both of which are amongst the best values ever reported for ZnO photodetectors. - Abstract: ZnO films with carrier concentration as low as 5.0 × 10{sup 13} cm{sup −3} have been prepared via a lithium and nitrogen codoping method, and ultraviolet photodetectors have been fabricated from the films. The photodetectors can be used to detect weak signals with power density as low as 20 nw/cm{sup 2}, and the detectivity and noise equivalent power of the photodetector can reach 3.60 × 10{sup 15} cmHz{sup 1/2}/W and 6.67 × 10{sup −18} W{sup −1}, respectively, both of which are amongst the best values ever reported for ZnO based photodetectors. The high-performance of the photodetector can be attributed to the relatively low carrier concentration of the ZnO:(Li,N) films.

Photonic antenna enhanced middle wave and longwave infrared focal plane array with low noise and high operating temperature, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Photodetectors and focal plane arrays (FPAs) covering the middle-wave and longwave infrared (MWIR/LWIR) are of great importance in numerous NASA applications,...

Low-noise, transformer-coupled resonant photodetector for squeezed state generation.

Science.gov (United States)

Chen, Chaoyong; Shi, Shaoping; Zheng, Yaohui

2017-10-01

In an actual setup of squeezed state generation, the stability of a squeezing factor is mainly limited by the performance of the servo-control system, which is mainly influenced by the shot noise and gain of a photodetector. We present a unique transformer-coupled LC resonant amplifier as a photodetector circuit to reduce the electronic noise and increase the gain of the photodetector. As a result, we obtain a low-noise, high gain photodetector with the gain of more than 1.8×10 5 V/A, and the input current noise of less than 4.7 pA/Hz. By adjusting the parameters of the transformer, the quality factor Q of the resonant circuit is close to 100 in the frequency range of more than 100 MHz, which meets the requirement for weak power detection in the application of squeezed state generation.

Carbon nanotube woven textile photodetector

Science.gov (United States)

Zubair, Ahmed; Wang, Xuan; Mirri, Francesca; Tsentalovich, Dmitri E.; Fujimura, Naoki; Suzuki, Daichi; Soundarapandian, Karuppasamy P.; Kawano, Yukio; Pasquali, Matteo; Kono, Junichiro

2018-01-01

The increasing interest in mobile and wearable technology demands the enhancement of functionality of clothing through incorporation of sophisticated architectures of multifunctional materials. Flexible electronic and photonic devices based on organic materials have made impressive progress over the past decade, but higher performance, simpler fabrication, and most importantly, compatibility with woven technology are desired. Here we report on the development of a weaved, substrateless, and polarization-sensitive photodetector based on doping-engineered fibers of highly aligned carbon nanotubes. This room-temperature-operating, self-powered detector responds to radiation in an ultrabroad spectral range, from the ultraviolet to the terahertz, through the photothermoelectric effect, with a low noise-equivalent power (a few nW/Hz 1 /2) throughout the range and with a Z T -factor value that is twice as large as that of previously reported carbon nanotube-based photothermoelectric photodetectors. Particularly, we fabricated a ˜1 -m-long device consisting of tens of p+-p- junctions and weaved it into a shirt. This device demonstrated a collective photoresponse of the series-connected junctions under global illumination. The performance of the device did not show any sign of deterioration through 200 bending tests with a bending radius smaller than 100 μ m as well as standard washing and ironing cycles. This unconventional photodetector will find applications in wearable technology that require detection of electromagnetic radiation.

Polarization-sensitive and broadband germanium sulfide photodetectors with excellent high-temperature performance.

Science.gov (United States)

Tan, Dezhi; Zhang, Wenjin; Wang, Xiaofan; Koirala, Sandhaya; Miyauchi, Yuhei; Matsuda, Kazunari

2017-08-31

Layered materials, such as graphene, transition metal dichalcogenides and black phosphorene, have been established rapidly as intriguing building blocks for optoelectronic devices. Here, we introduce highly polarization sensitive, broadband, and high-temperature-operation photodetectors based on multilayer germanium sulfide (GeS). The GeS photodetector shows a high photoresponsivity of about 6.8 × 10 3 A W -1 , an extremely high specific detectivity of 5.6 × 10 14 Jones, and broad spectral response in the wavelength range of 300-800 nm. More importantly, the GeS photodetector has high polarization sensitivity to incident linearly polarized light, which provides another degree of freedom for photodetectors. Tremendously enhanced photoresponsivity is observed with a temperature increase, and high responsivity is achievable at least up to 423 K. The establishment of larger photoinduced reduction of the Schottky barrier height will be significant for the investigation of the photoresponse mechanism of 2D layered material-based photodetectors. These attributes of high photocurrent generation in a wide temperature range, broad spectral response, and polarization sensitivity coupled with environmental stability indicate that the proposed GeS photodetector is very suitable for optoelectronic applications.

ZnSe MSM photodetectors prepared on GaAs and ZnSe substrates

International Nuclear Information System (INIS)

Lin, T.K.; Chang, S.J.; Su, Y.K.; Chiou, Y.Z.; Wang, C.K.; Chang, S.P.; Chang, C.M.; Tang, J.J.; Huang, B.R.

2005-01-01

Homoepitaxial and heteroepitaxial ZnSe metal-semiconductor-metal (MSM) photodetectors were both fabricated and characterized. It was found that homoepitaxial ZnSe MSM photodetector could provide us smaller dark current and large photocurrent. With an incident wavelength of 448 nm, it was found that the maximum responsivities for the homoepitaxial and heteroepitaxial ZnSe photodetectors were 0.128 and 0.045 A/W, which corresponds to a quantum efficiency of 36 and 12%, respectively. Furthermore, it was found that we achieved the minimum noise equivalent power (NEP) of 7.6 x 10 -13 W and the maximum normalized detectivity (D *) of 9.3 x 10 11 cm Hz 0.5 W -1 from our homoepitaxial ZnSe photodetector. In contrast, NEP and D * of the heteroepitaxial ZnSe photodetector were 2.9 x 10 -12 W and 2.44 x 10 11 cm Hz 0.5 W -1 , respectively

Conditions for a carrier multiplication in amorphous-selenium based photodetector

Energy Technology Data Exchange (ETDEWEB)

Masuzawa, Tomoaki; Kuniyoshi, Shingo; Onishi, Masanori; Kato, Richika; Saito, Ichitaro; Okano, Ken [Department of Material Science, International Christian University, S102 Science Hall, ICU, 3-10-2 Osawa, Mitaka, Tokyo 181-8585 (Japan); Yamada, Takatoshi [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, Tsukuba, Ibaraki 305-8568 (Japan); Koh, Angel T. T.; Chua, Daniel H. C. [Department of Materials Science and Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117574 (Singapore); Shimosawa, Tatsuo [Department of Clinical Laboratory, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-8655 (Japan)

2013-02-18

Amorphous selenium is a promising candidate for high sensitivity photodetector due to its unique carrier multiplication phenomenon. More than 10 carriers can be generated per incident photon, which leads to high photo-conversion efficiency of 1000% that allows real-time imaging in dark ambient. However, application of this effect has been limited to specific devices due to the lack in material characterization. In this article, mechanism of carrier multiplication has been clarified using time-of-flight secondary ion mass spectroscopy and Raman spectroscopy. A prototype photodetector achieved photo conversion efficiency of 4000%, which explains the signal enhancement mechanism in a-Se based photodetector.

Conditions for a carrier multiplication in amorphous-selenium based photodetector

International Nuclear Information System (INIS)

Masuzawa, Tomoaki; Kuniyoshi, Shingo; Onishi, Masanori; Kato, Richika; Saito, Ichitaro; Okano, Ken; Yamada, Takatoshi; Koh, Angel T. T.; Chua, Daniel H. C.; Shimosawa, Tatsuo

2013-01-01

Amorphous selenium is a promising candidate for high sensitivity photodetector due to its unique carrier multiplication phenomenon. More than 10 carriers can be generated per incident photon, which leads to high photo-conversion efficiency of 1000% that allows real-time imaging in dark ambient. However, application of this effect has been limited to specific devices due to the lack in material characterization. In this article, mechanism of carrier multiplication has been clarified using time-of-flight secondary ion mass spectroscopy and Raman spectroscopy. A prototype photodetector achieved photo conversion efficiency of 4000%, which explains the signal enhancement mechanism in a-Se based photodetector.

Photodetectors: Broad Detection Range Rhenium Diselenide Photodetector Enhanced by (3-Aminopropyl)Triethoxysilane and Triphenylphosphine Treatment (Adv. Mater. 31/2016).

Science.gov (United States)

Jo, Seo-Hyeon; Park, Hyung-Youl; Kang, Dong-Ho; Shim, Jaewoo; Jeon, Jaeho; Choi, Seunghyuk; Kim, Minwoo; Park, Yongkook; Lee, Jaehyeong; Song, Young Jae; Lee, Sungjoo; Park, Jin-Hong

2016-08-01

The effects of triphenylphosphine (PPh3 ) and (3-amino-propyl)triethoxysilane (APTES) on a rhenium diselenide (ReSe2 ) photodetector are systematically studied by J.-H. Park and co-workers on page 6711 in comparison with a conventional MoS2 device. A very high performance ReSe2 photodetector is demonstrated, which has a broad photodetection range, high photoresponsivity (1.18 × 10(6) A W(-1) ), and fast photoswitching speed (rising/decaying time: 58/263 ms). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Responsivity Enhanced NMOSFET Photodetector Fabricated by Standard CMOS Technology

Directory of Open Access Journals (Sweden)

Fuwei Wu

2015-01-01

Full Text Available Increasing the responsivity is one of the important issues for a photodetector. In this paper, we demonstrate an improved NMOSFET photodetector by using deep-n-well (DNW structure which can improve the responsivity of the photodetector significantly. The experimental results show that the responsivity can be enhanced greatly by the DNW structure and is much larger than the previous work when DNW is biased with 0.5 V, while the dark current exhibits almost no increase. Further characterization indicates that the diode formed by the bulk and DNW can efficiently absorb photons and has a large gain factor of the photocurrent especially under low light condition, which gives a more promising application for the detector to detect the weak light.

Ultra-efficient all-printed organic photodetectors

Science.gov (United States)

Kielar, Marcin; Dhez, Olivier; Hirsch, Lionel

2016-09-01

Organic photodetectors are able to transform plastic into intelligent surfaces making our daily life easier, smarter and more productive. The key element for a sensor is to reduce the dark current density in order to boost the limit of detection. The energetic requirements in order to select materials for ultra-high performance organic photodetectors are presented with the following experimental results: a detectivity of 3.36 × 1013 Jones has been achieved with an extremely low dark current density of 0.32 nA cm-2 and a responsivity as high as 0.34 A W-1. Flexible devices are all made at lowtemperature and with solution-processed materials. Their stability under operation is also presented.

Hybrid organic photodetectors for radiography

Energy Technology Data Exchange (ETDEWEB)

Buechele, Patric [Light Technology Institute, Karlsruhe Institute of Technology. Karlsruhe (Germany); Siemens AG. Corporate Technologies. Erlangen (Germany); Schmidt, Oliver; Tedde, Sandro; Hartmann, David [Siemens AG. Corporate Technologies. Erlangen (Germany); Richter, Moses [Institute for Materials for Electronics and Energy Technology, Friedrich-Alexander University. Erlangen (Germany); Lemmer, Uli [Light Technology Institute, Karlsruhe Institute of Technology. Karlsruhe (Germany)

2013-07-01

Most of todays X-ray detectors are using an indirect conversion mechanism. The X-ray radiation is converted into visible light within a thick scintillator layer. The visible light is then absorbed by standard thin-film photodetectors. The isotropic propagation of light in the scintillator reduces the resolution of the x-ray imager. This work avoids the stacked structure by integration of inorganic PbS quantum dots directly into the bulk hetero junction (BHJ) of an organic photodetector. X-ray photons are immediately converted into charge carriers and travel in direction of the electrical field towards the electrodes. However, this concept demands much thicker organic layers than known from conventional OLED and OPV processing. We demonstrate that thick diodes can be achieved with a spray coating process and the influence of spraying parameters on device performance is discussed.

Probing the nuclear and circumnuclear activity of NGC 1365 in the infrared

Science.gov (United States)

Alonso-Herrero, A.; Sánchez-Portal, M.; Ramos Almeida, C.; Pereira-Santaella, M.; Esquej, P.; García-Burillo, S.; Castillo, M.; González-Martín, O.; Levenson, N.; Hatziminaoglou, E.; Acosta-Pulido, J. A.; González-Serrano, J. I.; Pović, M.; Packham, C.; Pérez-García, A. M.

2012-09-01

We present new far-infrared (70-500 μm) Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) imaging observations as well as new mid-IR Gemini/Thermal-Region Camera Spectrograph imaging (8.7 and 18.3 μm) and spectroscopy of the inner Lindblad resonance (ILR) region (R Linares Senior Research Fellow.

High performance photodetector based on 2D CH3NH3PbI3 perovskite nanosheets

International Nuclear Information System (INIS)

Li, Pengfei; Shivananju, B N; Li, Shaojuan; Bao, Qiaoliang; Zhang, Yupeng

2017-01-01

In this work, a high performance vertical-type photodetector based on two-dimensional (2D) CH 3 NH 3 PbI 3 perovskite nanosheets was fabricated. The low trap density of the perovskite nanosheets and their short carrier diffusion distance result in a significant performance enhancement of the perovskite-based photodetector. The photoresponsivity of this vertical-type photodetector is as high as 36 mA W −1 at visible wavelength, which is much better than traditional perovskite photodetectors (0.34 mA W −1 ). Compared with traditional planar-type perovskite-based photodetectors, this vertical-type photodetector also shows the advantages of low-voltage operation and large responsivity. These results may pave the way for exploiting high performance perovskite-based photodetectors with an ingenious device design. (paper)

nBn Infrared Detector Containing Graded Absorption Layer

Science.gov (United States)

Gunapala, Sarath D.; Ting, David Z.; Hill, Cory J.; Bandara, Sumith V.

2009-01-01

It has been proposed to modify the basic structure of an nBn infrared photodetector so that a plain electron-donor- type (n-type) semiconductor contact layer would be replaced by a graded n-type III V alloy semiconductor layer (i.e., ternary or quarternary) with appropriate doping gradient. The abbreviation nBn refers to one aspect of the unmodified basic device structure: There is an electron-barrier ("B" ) layer between two n-type ("n" ) layers, as shown in the upper part of the figure. One of the n-type layers is the aforementioned photon-absorption layer; the other n-type layer, denoted the contact layer, collects the photocurrent. The basic unmodified device structure utilizes minority-charge-carrier conduction, such that, for reasons too complex to explain within the space available for this article, the dark current at a given temperature can be orders of magnitude lower (and, consequently, signal-to-noise ratios can be greater) than in infrared detectors of other types. Thus, to obtain a given level of performance, less cooling (and, consequently, less cooling equipment and less cooling power) is needed. [In principle, one could obtain the same advantages by means of a structure that would be called pBp because it would include a barrier layer between two electron-acceptor- type (p-type) layers.] The proposed modifications could make it practical to utilize nBn photodetectors in conjunction with readily available, compact thermoelectric coolers in diverse infrared- imaging applications that could include planetary exploration, industrial quality control, monitoring pollution, firefighting, law enforcement, and medical diagnosis.

Hyperspectral Longwave Infrared Focal Plane Array and Camera Based on Quantum Well Infrared Photodetectors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop a hyperspectral focal plane array and camera imaging in a large number of sharp hyperspectral bands in the thermal infrared. The camera is...

Device model for pixelless infrared image up-converters based on polycrystalline graphene heterostructures

Science.gov (United States)

Ryzhii, V.; Shur, M. S.; Ryzhii, M.; Karasik, V. E.; Otsuji, T.

2018-01-01

We developed a device model for pixelless converters of far/mid-infrared radiation (FIR/MIR) images into near-infrared/visible (NIR/VIR) images. These converters use polycrystalline graphene layers (PGLs) immersed in the van der Waals materials integrated with a light emitting diode (LED). The PGL serves as an element of the PGL infrared photodetector (PGLIP) sensitive to the incoming FIR/MIR due to the interband absorption. The spatially non-uniform photocurrent generated in the PGLIP repeats (mimics) the non-uniform distribution (image) created by the incident FIR/MIR. The injection of the nonuniform photocurrent into the LED active layer results in the nonuniform NIR/VIR image reproducing the FIR/MIR image. The PGL and the entire layer structure are not deliberately partitioned into pixels. We analyze the characteristics of such pixelless PGLIP-LED up-converters and show that their image contrast transfer function and the up-conversion efficiency depend on the PGL lateral resistivity. The up-converter exhibits high photoconductive gain and conversion efficiency when the lateral resistivity is sufficiently high. Several teams have successfully demonstrated the large area PGLs with the resistivities varying in a wide range. Such layers can be used in the pixelless PGLIP-LED image up-converters. The PGLIP-LED image up-converters can substantially surpass the image up-converters based on the quantum-well infrared photodetector integrated with the LED. These advantages are due to the use of the interband FIR/NIR absorption and a high photoconductive gain in the GLIPs.

SPIN-POLARIZED PHOTOCURRENT THROUGH QUANTUM DOT PHOTODETECTOR

Directory of Open Access Journals (Sweden)

Nguyen Van Hieu

2017-11-01

Full Text Available The theory of the photocurrent through the photodetector based on a two-level semiconductor quantum dot (QD is presented. The analytical expressions of the matrix elements of the electronic transitions generated by the absorption of the circularly polarized photons are derived in the lowest order of the perturbation theory with respect to the electron tunneling interaction as well as the electron-photon interaction. From these expressions the mechanism of the generation of the spin-polarized of electrons in the photocurrent is evident. It follows that the photodetector based on the two-level semiconductor QD can be used as the model of a source of highly spinpolarized electrons.

Thiol passivation of MWIR type II superlattice photodetectors

Science.gov (United States)

Salihoglu, O.; Muti, A.; Aydinli, A.

2013-06-01

Poor passivation on photodetectors can result in catastrophic failure of the device. Abrupt termination of mesa side walls during pixel definition generates dangling bonds that lead to inversion layers and surface traps leading to surface leakage currents that short circuit diode action. Good passivation, therefore, is critical in the fabrication of high performance devices. Silicondioxide has been the main stay of passivation for commercial photodetectors, deposited at high temperatures and high RF powers using plasma deposition techniques. In photodetectors based on III-V compounds, sulphur passivation has been shown to replace oxygen and saturate the dangling bonds. Despite its effectiveness, it degrades over time. More effort is required to create passivation layers which eliminate surface leakage current. In this work, we propose the use of sulphur based octadecanethiol (ODT), CH3(CH2)17SH, as a passivation layer for the InAs/GaSb superlattice photodetectors that acts as a self assembled monolayer (SAM). ODT SAMs consist of a chain of 18 carbon atoms with a sulphur atom at its head. ODT Thiol coating is a simple process that consist of dipping the sample into the solution for a prescribed time. Excellent electrical performance of diodes tested confirm the effectiveness of the sulphur head stabilized by the intermolecular interaction due to van der Walls forces between the long chains of ODT SAM which results in highly stable ultrathin hydrocarbon layers without long term degradation.

MgNiO-based metal-semiconductor- metal ultraviolet photodetector

International Nuclear Information System (INIS)

Zhao Yanmin; Zhang Jiying; Jiang Dayong; Shan Chongxin; Zhang Zhenzhong; Yao Bin; Zhao Dongxu; Shen Dezhen

2009-01-01

In this study, we report the growth of Mg x Ni 1-x O thin films on quartz substrates by electron beam evaporation. The absorption edge shows a blue shift from 340 nm to 260 nm with increase in the Mg content from 0.2 to 0.8. A metal-semiconductor-metal structured photodetector is fabricated from the Mg 0.2 Ni 0.8 O film. At a bias of 5 V, the dark current of the photodetector is about 70 nA. The maximum responsivity is about 147.3 μA W -1 at 320 nm. In addition, the ultraviolet (UV) (320 nm) to visible (400 nm) rejection ratio is nearly two orders of magnitude. Based on these results, it is proposed that Mg x Ni 1-x O is a potential candidate for application in UV photodetectors. (fast track communication)

Innovative mid-infrared detector concepts

Science.gov (United States)

Höfling, Sven; Pfenning, Andreas; Weih, Robert; Ratajczak, Albert; Hartmann, Fabian; Knebl, Georg; Kamp, Martin; Worschech, Lukas

2016-09-01

Gas sensing is a key technology with applications in various industrial, medical and environmental areas. Optical detection mechanisms allow for a highly selective, contactless and fast detection. For this purpose, rotational-vibrational absorption bands within the mid infrared (MIR) spectral region are exploited and probed with appropriate light sources. During the past years, the development of novel laser concepts such as interband cascade lasers (ICLs) and quantum cascade lasers (QCLs) has driven a continuous optimization of MIR laser sources. On the other hand side, there has been relatively little progress on detectors in this wavelength range. Here, we study two novel and promising GaSb-based detector concepts: Interband cascade detectors (ICD) and resonant tunneling diode (RTD) photodetectors. ICDs are a promising approach towards highly sensitive room temperature detection of MIR radiation. They make use of the cascading scheme that is enabled by the broken gap alignment of the two binaries GaSb and InAs. The interband transition in GaSb/InAs-superlattices (SL) allows for normal incidence detection. The cut-off wavelength, which determines the low energy detection limit, can be engineered via the SL period. RTD photodetectors act as low noise and high speed amplifiers of small optically generated electrical signals. In contrast to avalanche photodiodes, where the gain originates from multiplication due to impact ionization, in RTD photodetectors a large tunneling current is modulated via Coulomb interaction by the presence of photogenerated minority charge carriers. For both detector concepts, first devices operational at room temperature have been realized.

The properties of transparent TiO2 films for Schottky photodetector

Directory of Open Access Journals (Sweden)

Sung-Ho Park

2017-08-01

Full Text Available In this data, the properties of transparent TiO2 film for Schottky photodetector are presented for the research article, entitled as “High-performing transparent photodetectors based on Schottky contacts” (Patel et al., 2017 [1]. The transparent photoelectric device was demonstrated by using various Schottky metals, such as Cu, Mo and Ni. This article mainly shows the optical transmittance of the Ni-transparent Schottky photodetector, analyzed by the energy dispersive spectroscopy and interfacial TEM images for transparency to observe the interface between NiO and TiO2 film. The observation and analyses clearly show that no pinhole formation in the TiO2 film by Ni diffusion. The rapid thermal process is an effective way to form the quality TiO2 film formation without degradation, such as pinholes (Qiu et al., 2015 [2]. This thermal process may apply to form functional metal oxide layers for solar cells and photodetectors.

MgNiO-based metal-semiconductor- metal ultraviolet photodetector

Energy Technology Data Exchange (ETDEWEB)

Zhao Yanmin; Zhang Jiying; Jiang Dayong; Shan Chongxin; Zhang Zhenzhong; Yao Bin; Zhao Dongxu; Shen Dezhen, E-mail: zhangjy53@yahoo.com.c [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

2009-05-07

In this study, we report the growth of Mg{sub x}Ni{sub 1-x}O thin films on quartz substrates by electron beam evaporation. The absorption edge shows a blue shift from 340 nm to 260 nm with increase in the Mg content from 0.2 to 0.8. A metal-semiconductor-metal structured photodetector is fabricated from the Mg{sub 0.2}Ni{sub 0.8}O film. At a bias of 5 V, the dark current of the photodetector is about 70 nA. The maximum responsivity is about 147.3 {mu}A W{sup -1} at 320 nm. In addition, the ultraviolet (UV) (320 nm) to visible (400 nm) rejection ratio is nearly two orders of magnitude. Based on these results, it is proposed that Mg{sub x}Ni{sub 1-x}O is a potential candidate for application in UV photodetectors. (fast track communication)

High-Performance Single-Crystalline Perovskite Thin-Film Photodetector

KAUST Repository

Yang, Zhenqian

2018-01-10

The best performing modern optoelectronic devices rely on single-crystalline thin-film (SC-TF) semiconductors grown epitaxially. The emerging halide perovskites, which can be synthesized via low-cost solution-based methods, have achieved substantial success in various optoelectronic devices including solar cells, lasers, light-emitting diodes, and photodetectors. However, to date, the performance of these perovskite devices based on polycrystalline thin-film active layers lags behind the epitaxially grown semiconductor devices. Here, a photodetector based on SC-TF perovskite active layer is reported with a record performance of a 50 million gain, 70 GHz gain-bandwidth product, and a 100-photon level detection limit at 180 Hz modulation bandwidth, which as far as we know are the highest values among all the reported perovskite photodetectors. The superior performance of the device originates from replacing polycrystalline thin film by a thickness-optimized SC-TF with much higher mobility and longer recombination time. The results indicate that high-performance perovskite devices based on SC-TF may become competitive in modern optoelectronics.

History of HgTe-based photodetectors in Poland

Science.gov (United States)

Rogalski, A.

2010-09-01

In Poland, the HgCdTe studies began in 1960 at the Institute of Physics, Warsaw University. The material processing laboratory was created by Giriat and later by Dziuba, Gałązka, and others. Bridgman technique with sealed thick wall quartz ampoules was used to grow material suitable for research and experimental devices. Among the first papers published in 1961 and 1963 there were the Polish works devoted to preparation, doping, and electrical properties of HgCdTe. Infrared detector's research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapour phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition. At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics. In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.

Development of analog solid-state photo-detectors for Positron Emission Tomography

International Nuclear Information System (INIS)

Bisogni, Maria Giuseppina; Morrocchi, Matteo

2016-01-01

Solid-state photo-detectors are one of the main innovations of past century in the field of sensors. First produced in the early forties with the invention of the p–n junction in silicon and the study of its optical properties, photo-detectors received a major boost in the sixties when the p-i-n (PIN) photodiode was developed and successfully used in several applications. The development of devices with internal gain, avalanche photodiodes (APD) first and then Geiger-mode avalanche photodiodes, named single photon avalanche diode (SPAD), leads to a substantial improvement in sensitivity and allowed single photon detection. Later on, thousands of SPADs have been assembled in arrays of few millimeters squared (named SiPM, silicon photo-multiplier) with single photon resolution. The high internal gain of SiPMs, together with other features peculiar of the silicon technology like compactness, speed and compatibility with magnetic fields, promoted SiPMs as the principal photo-detector competitor of photomultipliers in many applications from radiation detection to medical imaging. This paper provides a review of the properties of analog solid-state photo-detectors. Particular emphasis is given to latest advances on Positron Emission Tomography instrumentation boosted by the adoption of the silicon photo-detectors as an alternative to photomultiplier tubes (PMTs). Special attention is dedicated to the SiPMs, which are playing a key role in the development of innovative scanners.

Development of analog solid-state photo-detectors for Positron Emission Tomography

Energy Technology Data Exchange (ETDEWEB)

Bisogni, Maria Giuseppina, E-mail: giuseppina.bisogni@pi.infn.it; Morrocchi, Matteo

2016-02-11

Solid-state photo-detectors are one of the main innovations of past century in the field of sensors. First produced in the early forties with the invention of the p–n junction in silicon and the study of its optical properties, photo-detectors received a major boost in the sixties when the p-i-n (PIN) photodiode was developed and successfully used in several applications. The development of devices with internal gain, avalanche photodiodes (APD) first and then Geiger-mode avalanche photodiodes, named single photon avalanche diode (SPAD), leads to a substantial improvement in sensitivity and allowed single photon detection. Later on, thousands of SPADs have been assembled in arrays of few millimeters squared (named SiPM, silicon photo-multiplier) with single photon resolution. The high internal gain of SiPMs, together with other features peculiar of the silicon technology like compactness, speed and compatibility with magnetic fields, promoted SiPMs as the principal photo-detector competitor of photomultipliers in many applications from radiation detection to medical imaging. This paper provides a review of the properties of analog solid-state photo-detectors. Particular emphasis is given to latest advances on Positron Emission Tomography instrumentation boosted by the adoption of the silicon photo-detectors as an alternative to photomultiplier tubes (PMTs). Special attention is dedicated to the SiPMs, which are playing a key role in the development of innovative scanners.

Periodically structured Si pillars for high-performing heterojunction photodetectors

Science.gov (United States)

Melvin David Kumar, M.; Yun, Ju-Hyung; Kim, Joondong

2015-03-01

A periodical array of silicon (Si) micro pillar structures was fabricated on Si substrates using PR etching process. Indium tin oxide (ITO) layer of 80 nm thickness was deposited over patterned Si substrates so as to make ITO/n-Si heterojunction devices. The influences of width and period of pillars on the optical and electrical properties of prepared devices were investigated. The surface morphology of the Si substrates revealed the uniform array of pillar structures. The 5/10 (width/period) Si pillar pattern reduced the optical reflectance to 6.5% from 17% which is of 5/7 pillar pattern. The current rectifying ratio was found higher for the device in which the pillars are situated in optimum periods. At both visible (600 nm) and near infrared (900 nm) range of wavelengths, the 5/7 and 5/10 pillar patterned device exhibited the better photoresponses which are suitable for making advanced photodetectors. This highly transmittance and photoresponsive pillar patterned Si substrates with an ITO layer would be a promising device for various photoelectric applications.

Photovoltaic-Pyroelectric Coupled Effect Induced Electricity for Self-Powered Photodetector System.

Science.gov (United States)

Ma, Nan; Zhang, Kewei; Yang, Ya

2017-12-01

Ferroelectric materials have demonstrated novel photovoltaic effect to scavenge solar energy. However, most of the ferroelectric materials with wide bandgaps (2.7-4 eV) suffer from low power conversion efficiency of less than 0.5% due to absorbing only 8-20% of solar spectrum. Instead of harvesting solar energy, these ferroelectric materials can be well suited for photodetector applications, especially for sensing near-UV irradiations. Here, a ferroelectric BaTiO 3 film-based photodetector is demonstrated that can be operated without using any external power source and a fast sensing of 405 nm light illumination is enabled. As compared with photovoltaic effect, both the responsivity and the specific detectivity of the photodetector can be dramatically enhanced by larger than 260% due to the light-induced photovoltaic-pyroelectric coupled effect. A self-powered photodetector array system can be utilized to achieve spatially resolved light intensity detection by recording the output voltage signals as a mapping figure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emerging technologies for high performance infrared detectors

Science.gov (United States)

Tan, Chee Leong; Mohseni, Hooman

2018-01-01

Infrared photodetectors (IRPDs) have become important devices in various applications such as night vision, military missile tracking, medical imaging, industry defect imaging, environmental sensing, and exoplanet exploration. Mature semiconductor technologies such as mercury cadmium telluride and III-V material-based photodetectors have been dominating the industry. However, in the last few decades, significant funding and research has been focused to improve the performance of IRPDs such as lowering the fabrication cost, simplifying the fabrication processes, increasing the production yield, and increasing the operating temperature by making use of advances in nanofabrication and nanotechnology. We will first review the nanomaterial with suitable electronic and mechanical properties, such as two-dimensional material, graphene, transition metal dichalcogenides, and metal oxides. We compare these with more traditional low-dimensional material such as quantum well, quantum dot, quantum dot in well, semiconductor superlattice, nanowires, nanotube, and colloid quantum dot. We will also review the nanostructures used for enhanced light-matter interaction to boost the IRPD sensitivity. These include nanostructured antireflection coatings, optical antennas, plasmonic, and metamaterials.

Emerging technologies for high performance infrared detectors

Directory of Open Access Journals (Sweden)

Tan Chee Leong

2018-01-01

Full Text Available Infrared photodetectors (IRPDs have become important devices in various applications such as night vision, military missile tracking, medical imaging, industry defect imaging, environmental sensing, and exoplanet exploration. Mature semiconductor technologies such as mercury cadmium telluride and III–V material-based photodetectors have been dominating the industry. However, in the last few decades, significant funding and research has been focused to improve the performance of IRPDs such as lowering the fabrication cost, simplifying the fabrication processes, increasing the production yield, and increasing the operating temperature by making use of advances in nanofabrication and nanotechnology. We will first review the nanomaterial with suitable electronic and mechanical properties, such as two-dimensional material, graphene, transition metal dichalcogenides, and metal oxides. We compare these with more traditional low-dimensional material such as quantum well, quantum dot, quantum dot in well, semiconductor superlattice, nanowires, nanotube, and colloid quantum dot. We will also review the nanostructures used for enhanced light-matter interaction to boost the IRPD sensitivity. These include nanostructured antireflection coatings, optical antennas, plasmonic, and metamaterials.

Hexagonal-like Nb2O5 Nanoplates-Based Photodetectors and Photocatalyst with High Performances

Science.gov (United States)

Liu, Hui; Gao, Nan; Liao, Meiyong; Fang, Xiaosheng

2015-01-01

Ultraviolet (UV) photodetectors are important tools in the fields of optical imaging, environmental monitoring, and air and water sterilization, as well as flame sensing and early rocket plume detection. Herein, hexagonal-like Nb2O5 nanoplates are synthesized using a facile solvothermal method. UV photodetectors based on single Nb2O5 nanoplates are constructed and the optoelectronic properties have been probed. The photodetectors show remarkable sensitivity with a high external quantum efficiency (EQE) of 9617%, and adequate wavelength selectivity with respect to UV-A light. In addition, the photodetectors exhibit robust stability and strong dependence of photocurrent on light intensity. Also, a low-cost drop-casting method is used to fabricate photodetectors based on Nb2O5 nanoplate film, which exhibit singular thermal stability. Moreover, the hexagonal-like Nb2O5 nanoplates show significantly better photocatalytic performances in decomposing Methylene-blue and Rhdamine B dyes than commercial Nb2O5.

Large-aperture hybrid photo-detector

International Nuclear Information System (INIS)

Kawai, Y.; Nakayama, H.; Kusaka, A.; Kakuno, H.; Abe, T.; Iwasaki, M.; Aihara, H.; Tanaka, M.; Shiozawa, M.; Kyushima, H.; Suyama, M.

2007-01-01

We have developed the first complete large-aperture (13-inch diameter) hybrid photo-detector (HPD). The withstanding voltage problem has been overcome and we were able to attain an HPD operating voltage of +20 kV. Adoption of our newly developed backside illumination avalanche diode (AD) was also critical in successfully countering the additional problem of an increase in AD leakage after the activation process. We observed single photon signal timing jitter of under 450 ps in FWHM, electron transit time of ∼12 ns, and clear pulse height separation up to several photoelectron peaks, all greatly superior to the performance of any conventional large-aperture photomultiplier tubes (PMTs). In addition, our HPD has a much simpler structure than conventional large-aperture PMTs, which simplifies mass production and lowers manufacturing cost. We believe that these attributes position our HPD as the most suitable photo-detector for the next generation mega-ton class water-Cherenkov detector, which is expected to be more than 20x larger than the Super-Kamiokande (SK) detector

Highly Deformable Origami Paper Photodetector Arrays

KAUST Repository

Lin, Chun-Ho

2017-09-25

Flexible electronics will form the basis of many next-generation technologies, such as wearable devices, biomedical sensors, the Internet of things, and more. However, most flexible devices can bear strains of less than 300% as a result of stretching. In this work, we demonstrate a simple and low-cost paper-based photodetector array featuring superior deformability using printable ZnO nanowires, carbon electrodes, and origami-based techniques. With a folded Miura structure, the paper photodetector array can be oriented in four different directions via tessellated parallelograms to provide the device with excellent omnidirectional light harvesting capabilities. Additionally, we demonstrate that the device can be repeatedly stretched (up to 1000% strain), bent (bending angle ±30°), and twisted (up to 360°) without degrading performance as a result of the paper folding technique, which enables the ZnO nanowire layers to remain rigid even as the device is deformed. The origami-based strategy described herein suggests avenues for the development of next-generation deformable optoelectronic applications.

High-speed 1.3 -1.55 um InGaAs/InP PIN photodetector for microwave photonics

Science.gov (United States)

Kozyreva, O. A.; Solov'ev, Y. V.; Polukhin, I. S.; Mikhailov, A. K.; Mikhailovskiy, G. A.; Odnoblyudov, M. A.; Gareev, E. Z.; Kolodeznyi, E. S.; Novikov, I. I.; Karachinsky, L. Ya; Egorov, A. Yu; Bougrov, V. E.

2017-11-01

We have fabricated the 1.3-1.55 um PIN photodetector based on InGaAs/InP heterostructure. Measurement results of optical and electrical characteristics of PIN photodetector chip were the following: photoconductivity at 1550 nm was 0.65 A/W and internal capacitance was 0.025 pF. Microwave model of photodetector was developed and verified by measurements of scattering matrix. The implementation of broadband (up to 20 GHz) hybrid integrated matching and biasing circuit for high-speed photodetector is presented.

Recent Developments in Quantum-Well Infrared Photodetectors

Science.gov (United States)

Gunapala, S. D.; Bandara, K. M. S. V.

1995-01-01

Intrinsic infrared (IR) detectors in the long wavelength range (8-20 Am) are based on an optically excited interband transition, which promotes an electron across the band gap (E(sub g)) from the valence band to the conduction band as shown. These photoelectrons can be collected efficiently, thereby producing a photocurrent in the external circuit. Since the incoming photon has to promote an electron from the valence band to the conduction band, the energy of the photon (h(sub upsilon)) must be higher than the E(sub g) of the photosensitive material. Therefore, the spectral response of the detectors can be controlled by controlling the E(sub g) of the photosensitive material. Examples for such materials are Hg(1-x), Cd(x), Te, and Pb(1-x), Sn(x), Te, in which the energy gap can be controlled by varying x. This means detection of very-long-wavelength IR radiation up to 20 microns requires small band gaps down to 62 meV. It is well known that these low band gap materials, characterized by weak bonding and low melting points, are more difficult to grow and process than large-band gap semiconductors such as GaAs. These difficulties motivate the exploration of utilizing the intersub-band transitions in multiquantum well (MQW) structures made of more refractory large-band gap semiconductors. The idea of using MQW structures to detect IR radiation can be explained by using the basic principles of quantum mechanics. The quantum well is equivalent to the well-known particle in a box problem in quantum mechanics, which can be solved by the time independent Schroudiner equation.

Flexible ultraviolet photodetectors based on ZnO-SnO2 heterojunction nanowire arrays

Science.gov (United States)

Lou, Zheng; Yang, Xiaoli; Chen, Haoran; Liang, Zhongzhu

2018-02-01

A ZnO-SnO2 nanowires (NWs) array, as a metal oxide semiconductor, was successfully synthesized by a near-field electrospinning method for the applications as high performance ultraviolet photodetectors. Ultraviolet photodetectors based on a single nanowire exhibited excellent photoresponse properties to 300 nm ultraviolet light illumination including ultrahigh I on/I off ratios (up to 103), good stability and reproducibility because of the separation between photo-generated electron-hole pairs. Moreover, the NWs array shows an enhanced photosensing performance. Flexible photodetectors on the PI substrates with similar tendency properties were also fabricated. In addition, under various bending curvatures and cycles, the as-fabricated flexible photodetectors revealed mechanical flexibility and good stable electrical properties, showing that they have the potential for applications in future flexible photoelectron devices. Project supported by the National Science Foundation of China (No. 61504136) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine and Physics, Chinese Academy of Sciences.

Room-temperature nine-µm-wavelength photodetectors and GHz-frequency heterodyne receivers

Science.gov (United States)

Palaferri, Daniele; Todorov, Yanko; Bigioli, Azzurra; Mottaghizadeh, Alireza; Gacemi, Djamal; Calabrese, Allegra; Vasanelli, Angela; Li, Lianhe; Davies, A. Giles; Linfield, Edmund H.; Kapsalidis, Filippos; Beck, Mattias; Faist, Jérôme; Sirtori, Carlo

2018-04-01

Room-temperature operation is essential for any optoelectronics technology that aims to provide low-cost, compact systems for widespread applications. A recent technological advance in this direction is bolometric detection for thermal imaging, which has achieved relatively high sensitivity and video rates (about 60 hertz) at room temperature. However, owing to thermally induced dark current, room-temperature operation is still a great challenge for semiconductor photodetectors targeting the wavelength band between 8 and 12 micrometres, and all relevant applications, such as imaging, environmental remote sensing and laser-based free-space communication, have been realized at low temperatures. For these devices, high sensitivity and high speed have never been compatible with high-temperature operation. Here we show that a long-wavelength (nine micrometres) infrared quantum-well photodetector fabricated from a metamaterial made of sub-wavelength metallic resonators exhibits strongly enhanced performance with respect to the state of the art up to room temperature. This occurs because the photonic collection area of each resonator is much larger than its electrical area, thus substantially reducing the dark current of the device. Furthermore, we show that our photonic architecture overcomes intrinsic limitations of the material, such as the drop of the electronic drift velocity with temperature, which constrains conventional geometries at cryogenic operation. Finally, the reduced physical area of the device and its increased responsivity allow us to take advantage of the intrinsic high-frequency response of the quantum detector at room temperature. By mixing the frequencies of two quantum-cascade lasers on the detector, which acts as a heterodyne receiver, we have measured a high-frequency signal, above four gigahertz (GHz). Therefore, these wide-band uncooled detectors could benefit technologies such as high-speed (gigabits per second) multichannel coherent data

Photodetectors based on carbon nanotubes deposited by using a spray technique on semi-insulating gallium arsenide

Directory of Open Access Journals (Sweden)

Domenico Melisi

2014-11-01

Full Text Available In this paper, a spray technique is used to perform low temperature deposition of multi-wall carbon nanotubes on semi-insulating gallium arsenide in order to obtain photodectors. A dispersion of nanotube powder in non-polar 1,2-dichloroethane is used as starting material. The morphological properties of the deposited films has been analysed by means of electron microscopy, in scanning and transmission mode. Detectors with different layouts have been prepared and current–voltage characteristics have been recorded in the dark and under irradiation with light in the range from ultraviolet to near infrared. The device spectral efficiency obtained from the electrical characterization is finally reported and an improvement of the photodetector behavior due to the nanotubes is presented and discussed.

2D/0D graphene hybrids for visible-blind flexible UV photodetectors.

Science.gov (United States)

Tetsuka, Hiroyuki

2017-07-17

Nitrogen-functionalized graphene quantum dots (NGQDs) are attractive building blocks for optoelectronic devices because of their exceptional tunable optical absorption and fluorescence properties. Here, we developed a high-performance flexible NGQD/graphene field-effect transistor (NGQD@GFET) hybrid ultraviolet (UV) photodetector, using dimethylamine-functionalized GQDs (NMe 2 -GQDs) with a large bandgap of ca. 3.3 eV. The NMe 2 -GQD@GFET photodetector exhibits high photoresponsivity and detectivity of ca. 1.5 × 10 4  A W -1 and ca. 5.5 × 10 11 Jones, respectively, in the deep-UV region as short as 255 nm without application of a backgate voltage. The feasibility of these flexible UV photodetectors for practical application in flame alarms is also demonstrated.

High-Performance solar-blind flexible Deep-UV photodetectors based on quantum dots synthesized by femtosecond-laser ablation

KAUST Repository

Mitra, Somak

2018-03-31

High-performance deep ultraviolet (DUV) photodetectors operating at ambient conditions with < 280nm detection wavelengths are in high demand because of their potential applications in diverse fields. We demonstrate for the first time, high-performance flexible DUV photodetectors operating at ambient conditions based on quantum dots (QDs) synthesized by femtosecond-laser ablation in liquid (FLAL) technique. Our method is facile without complex chemical procedures, which allows large-scale cost-effective devices. This synthesis method is demonstrated to produce highly stable and reproducible ZnO QDs from zinc nitride target (Zn3N2) without any material degradation due to water and oxygen molecule species, allowing photodetectors operate at ambient conditions. Carbon-doped ZnO QD-based photodetector is capable of detecting efficiently in the DUV spectral region, down to 224nm, and exhibits high photo responsivity and stability. As fast response of DUV photodetector remains significant parameter for high-speed communication; we show fast-response QD-based DUV photodetector. Such surfactant-free synthesis by FLAL can lead to commercially available high-performance low-cost optoelectronic devices based on nanostructures for large scale applications.

Porous-shaped silicon carbide ultraviolet photodetectors on porous silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Naderi, N., E-mail: naderi.phd@gmail.com [Nano-Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hashim, M.R. [Nano-Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

2013-03-05

Highlights: ► Porous-shaped silicon carbide thin film was deposited on porous silicon substrate. ► Thermal annealing was followed to enhance the physical properties of samples. ► Metal–semiconductor-metal ultraviolet detectors were fabricated on samples. ► The effect of annealing temperature on electrical performance of devices was studied. ► The efficiency of photodetectors was enhanced by annealing at elevated temperatures. -- Abstract: A metal–semiconductor-metal (MSM) ultraviolet photodetector was fabricated based on a porous-shaped structure of silicon carbide (SiC). For increasing the surface roughness of SiC and hence enhancing the light absorption effect in fabricated devices, porous silicon (PS) was chosen as a template; SiC was deposited on PS substrates via radio frequency magnetron sputtering. Therefore, the deposited layers followed the structural pattern of PS skeleton and formed a porous-shaped SiC layer on PS substrate. The structural properties of samples showed that the as-deposited SiC was amorphous. Thus, a post-deposition annealing process with elevated temperatures was required to convert its amorphous phase to crystalline phase. The morphology of the sputtered samples was examined via scanning electron and atomic force microscopies. The grain size and roughness of the deposited layers clearly increased upon an increase in the annealing temperature. The optical properties of sputtered SiC were enhanced due to applying high temperatures. The most intense photoluminescence peak was observed for the sample with 1200 °C of annealing temperature. For the metallization of the SiC substrates to fabricate MSM photodetectors, two interdigitated Schottky contacts of Ni with four fingers for each electrode were deposited onto all the porous substrates. The optoelectronic characteristics of MSM UV photodetectors with porous-shaped SiC substrates were studied in the dark and under UV illumination. The electrical characteristics of fabricated

Porous-shaped silicon carbide ultraviolet photodetectors on porous silicon substrates

International Nuclear Information System (INIS)

Naderi, N.; Hashim, M.R.

2013-01-01

Highlights: ► Porous-shaped silicon carbide thin film was deposited on porous silicon substrate. ► Thermal annealing was followed to enhance the physical properties of samples. ► Metal–semiconductor-metal ultraviolet detectors were fabricated on samples. ► The effect of annealing temperature on electrical performance of devices was studied. ► The efficiency of photodetectors was enhanced by annealing at elevated temperatures. -- Abstract: A metal–semiconductor-metal (MSM) ultraviolet photodetector was fabricated based on a porous-shaped structure of silicon carbide (SiC). For increasing the surface roughness of SiC and hence enhancing the light absorption effect in fabricated devices, porous silicon (PS) was chosen as a template; SiC was deposited on PS substrates via radio frequency magnetron sputtering. Therefore, the deposited layers followed the structural pattern of PS skeleton and formed a porous-shaped SiC layer on PS substrate. The structural properties of samples showed that the as-deposited SiC was amorphous. Thus, a post-deposition annealing process with elevated temperatures was required to convert its amorphous phase to crystalline phase. The morphology of the sputtered samples was examined via scanning electron and atomic force microscopies. The grain size and roughness of the deposited layers clearly increased upon an increase in the annealing temperature. The optical properties of sputtered SiC were enhanced due to applying high temperatures. The most intense photoluminescence peak was observed for the sample with 1200 °C of annealing temperature. For the metallization of the SiC substrates to fabricate MSM photodetectors, two interdigitated Schottky contacts of Ni with four fingers for each electrode were deposited onto all the porous substrates. The optoelectronic characteristics of MSM UV photodetectors with porous-shaped SiC substrates were studied in the dark and under UV illumination. The electrical characteristics of fabricated

Simulation of high SNR photodetector with L-C coupling and transimpedance amplifier circuit and its verification

Science.gov (United States)

Wang, Shaofeng; Xiang, Xiao; Zhou, Conghua; Zhai, Yiwei; Quan, Runai; Wang, Mengmeng; Hou, Feiyan; Zhang, Shougang; Dong, Ruifang; Liu, Tao

2017-01-01

In this paper, a model for simulating the optical response and noise performances of photodetectors with L-C coupling and transimpedance amplification circuit is presented. To verify the simulation, two kinds of photodetectors, which are based on the same printed-circuit-board (PCB) designing and PIN photodiode but different operational amplifiers, are developed and experimentally investigated. Through the comparisons between the numerical simulation results and the experimentally obtained data, excellent agreements are achieved, which show that the model provides a highly efficient guide for the development of a high signal to noise ratio photodetector. Furthermore, the parasite capacitances on the developed PCB, which are always hardly measured but play a non-negligible influence on the photodetectors' performances, are estimated.

Self-powered photogalvanic phosphorene photodetectors with high polarization sensitivity and suppressed dark current.

Science.gov (United States)

Li, Shuaishuai; Wang, Tao; Chen, Xiaoshuang; Lu, Wei; Xie, Yiqun; Hu, Yibin

2018-04-26

High polarization sensitivity, suppressed dark current and low energy consumption are all desirable device properties for photodetectors. In this work, we propose phosphorene-based photodetectors that are driven using photogalvanic effects (PGEs). The inversion symmetry of pristine phosphorene is broken using either application of an out-of-plane gate voltage or a heterostructure that is composed of the original phosphorene and blue phosphorene. The potential asymmetry enables PGEs under illumination by polarized light. Quantum transport calculations show that robust photocurrents are indeed generated by PGEs under a zero external bias voltage because of the broken inversion symmetry. These results indicate that the proposed photodetector is self-powered. In addition, the zero bias voltage eliminates the dark currents that are caused by application of an external bias voltage to traditional photodetectors. High polarization sensitivity to both linearly and circularly polarized light can also be realized, with extinction ratios ranging up to 102. The photoresponse of the proposed phosphorene/blue phosphorene heterostructure can be greatly enhanced by gating and is several orders of magnitude higher than that in gated phosphorene.

Employment of a metal microgrid as a front electrode in a sandwich-structured photodetector.

Science.gov (United States)

Zhang, Junying; Cai, Chao; Pan, Feng; Hao, Weichang; Zhang, Weiwei; Wang, Tianmin

2009-07-01

A highly UV-transparent metal microgrid was prepared and employed as the front electrode in a sandwich-structured ultraviolet (UV) photodetector using TiO(2) thin film as the semiconductor layer. The photo-generated charger carriers travel a shorter distance before reaching the electrodes in comparison with a photodetector using large-spaced interdigitated metal electrodes (where distance between fingers is several to tens of micrometers) on the surface of the semiconductor film. This photodetector responds to UV light irradiation, and the photocurrent intensity increases linearly with the irradiation intensity below 0.2 mW/cm(2).

Modulation Transfer Function of Infrared Focal Plane Arrays

Science.gov (United States)

Gunapala, S. D.; Rafol, S. B.; Ting, D. Z.; Soibel, A.; Hill, C. J.; Khoshakhlagh, A.; Liu, J. K.; Mumolo, J. M.; Hoglund, L.; Luong, E. M.

2015-01-01

Modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels mid -wavelength and long- wavelength quantum well infrared photodetector, and 320x256 pixels long- wavelength InAs/GaSb superlattice infrared focal plane arrays (FPAs). Long wavelength Complementary Barrier Infrared Detector (CBIRD) based on InAs/GaSb superlattice material is hybridized to recently designed and fabricated 320x256 pixel format ROIC. The n-type CBIRD was characterized in terms of performance and thermal stability. The experimentally measured NE delta T of the 8.8 micron cutoff n-CBIRD FPA was 18.6 mK with 300 K background and f/2 cold stop at 78K FPA operating temperature. The horizontal and vertical MTFs of this pixel fully delineated CBIRD FPA at Nyquist frequency are 49% and 52%, respectively.

Design and development of wafer-level near-infrared micro-camera

Science.gov (United States)

Zeller, John W.; Rouse, Caitlin; Efstathiadis, Harry; Haldar, Pradeep; Dhar, Nibir K.; Lewis, Jay S.; Wijewarnasuriya, Priyalal; Puri, Yash R.; Sood, Ashok K.

2015-08-01

SiGe offers a low-cost alternative to conventional infrared sensor material systems such as InGaAs, InSb, and HgCdTe for developing near-infrared (NIR) photodetector devices that do not require cooling and can offer high bandwidths and responsivities. As a result of the significant difference in thermal expansion coefficients between germanium and silicon, tensile strain incorporated into Ge epitaxial layers deposited on Si utilizing specialized growth processes can extend the operational range of detection to 1600 nm and longer wavelengths. We have fabricated SiGe based PIN detector devices on 300 mm diameter Si wafers in order to take advantage of high throughput, large-area complementary metal-oxide semiconductor (CMOS) technology. This device fabrication process involves low temperature epitaxial deposition of Ge to form a thin p+ seed/buffer layer, followed by higher temperature deposition of a thicker Ge intrinsic layer. An n+-Ge layer formed by ion implantation of phosphorus, passivating oxide cap, and then top copper contacts complete the PIN photodetector design. Various techniques including transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) have been employed to characterize the material and structural properties of the epitaxial growth and fabricated detector devices. In addition, electrical characterization was performed to compare the I-V dark current vs. photocurrent response as well as the time and wavelength varying photoresponse properties of the fabricated devices, results of which are likewise presented.

Increasing sensitivity and angle-of-view of mid-wave infrared detectors by integration with dielectric microspheres

Energy Technology Data Exchange (ETDEWEB)

Allen, Kenneth W., E-mail: kenneth.allen@gtri.gatech.edu; Astratov, Vasily N., E-mail: astratov@uncc.edu [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); UES, Dayton, Ohio 45433 (United States); Abolmaali, Farzaneh [Department of Physics and Optical Science, Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, Charlotte, North Carolina 28223-0001 (United States); Duran, Joshua M.; Ariyawansa, Gamini; Limberopoulos, Nicholaos I. [Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433 (United States); Urbas, Augustine M. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson AFB, Ohio 45433 (United States)

2016-06-13

We observed up to 100 times enhancement of sensitivity of mid-wave infrared photodetectors in the 2–5 μm range by using photonic jets produced by sapphire, polystyrene, and soda-lime glass microspheres with diameters in the 90–300 μm range. By finite-difference time-domain (FDTD) method for modeling, we gain insight into the role of the microspheres refractive index, size, and alignment with respect to the detector mesa. A combination of enhanced sensitivity with angle-of-view (AOV) up to 20° is demonstrated for individual photodetectors. It is proposed that integration with microspheres can be scaled up for large focal plane arrays, which should provide maximal light collection efficiencies with wide AOVs, a combination of properties highly attractive for imaging applications.

The controlled growth of graphene nanowalls on Si for Schottky photodetector

Directory of Open Access Journals (Sweden)

Quan Zhou

2017-12-01

Full Text Available Schottky diode with directly-grown graphene on silicon substrate has advantage of clean junction interface, promising for photodetectors with high-speed and low noise. In this report, we carefully studied the influence of growth parameters on the junction quality and photoresponse of graphene nanowalls (GNWs-based Schottky photodetectors. We found that shorter growth time is critical for lower dark current, but at the same time higher photocurrent. The influence of growth parameters was attributed to the defect density of various growth time, which results in different degrees of surface absorption for H2O/O2 molecules and P-type doping level. Raman characterization and vacuum annealing treatment were carried out to confirm the regulation mechanism. Meanwhile, the release of thermal stress also makes the ideality factor η of thinner sample better than the thicker. Our results are important for the response improvement of photodetectors with graphene-Si schottky junction.

Simulation of optimum parameters for GaN MSM UV photodetector

Energy Technology Data Exchange (ETDEWEB)

Alhelfi, Mohanad A., E-mail: mhad12344@gmail.com; Ahmed, Naser M., E-mail: nas-tiji@yahoo.com; Hashim, M. R., E-mail: roslan@usm.my; Hassan, Z., E-mail: zai@usm.my [Institue of Nano-Optoelectronics Research and Technology (INOR), School of Physics, Universiti Sains Malaysia 11800 Penang (Malaysia); Al-Rawi, Ali Amer, E-mail: aliamer@unimap.edu.my [School of Computer and Communication Eng. 3st Floor, Pauh Putra Main Campus 02600 Arau, Perlis Malaysia (Malaysia)

2016-07-06

In this study the optimum parameters of GaN M-S-M photodetector are discussed. The evaluation of the photodetector depends on many parameters, the most of the important parameters the quality of the GaN film and others depend on the geometry of the interdigited electrode. In this simulation work using MATLAB software with consideration of the reflection and absorption on the metal contacts, a detailed study involving various electrode spacings (S) and widths (W) reveals conclusive results in device design. The optimum interelectrode design for interdigitated MSM-PD has been specified and evaluated by effect on quantum efficiency and responsivity.

Optical properties of photodetectors based on single GaN nanowires with a transparent graphene contact

Energy Technology Data Exchange (ETDEWEB)

Babichev, A. V., E-mail: A.Babichev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Institute (Russian Federation); Zhang, H.; Guan, N. [University Paris Saclay, Institut d’Electronique Fondamentale, UMR 8622 CNRS (France); Egorov, A. Yu. [ITMO University (Russian Federation); Julien, F. H.; Messanvi, A. [University Paris Saclay, Institut d’Electronique Fondamentale, UMR 8622 CNRS (France); Durand, C.; Eymery, J. [University Grenoble Alpes (France); Tchernycheva, M. [University Paris Saclay, Institut d’Electronique Fondamentale, UMR 8622 CNRS (France)

2016-08-15

We report the fabrication and optical and electrical characterization of photodetectors for the UV spectral range based on single p–n junction nanowires with a transparent contact of a new type. The contact is based on CVD-grown (chemical-vapor deposition) graphene. The active region of the nitride nanowires contains a set of 30 radial In{sub 0.18}Ga{sub 0.82}N/GaN quantum wells. The structure is grown by metal-organic vaporphase epitaxy. The photodetectors are fabricated using electron-beam lithography. The current–voltage characteristics exhibit a rectifying behavior. The spectral sensitivity of the photodetector is recorded starting from 3 eV and extending far in the UV range. The maximal photoresponse is observed at a wavelength of 367 nm (sensitivity 1.9 mA/W). The response switching time of the photodetector is less than 0.1 s.

Modelling of current-voltage characteristics of infrared photo-detectors based on type – II InAs/GaSb super-lattice diodes with unipolar blocking layers

Directory of Open Access Journals (Sweden)

Vishnu Gopal

2015-09-01

Full Text Available It is shown that current-voltage characteristics of infrared photo-detectors based on type-II InAs/GaSb super-lattices with uni-polar blocking layers can be modelled similar to a junction diode with a finite series resistance on account of blocking barriers. As an example this paper presents the results of a study of current-voltage characteristics of a type II InAs/GaSb super-lattice diode with PbIbN architecture using a recently proposed [J. Appl. Phys. 116, 084502 (2014] method for modelling of illuminated photovoltaic detectors. The thermal diffusion, generation – recombination (g-r, and ohmic currents are found as principal components besides a component of photocurrent due to background illumination. The experimentally observed reverse bias diode current in excess of thermal current (diffusion + g-r, photo-current and ohmic shunt current is reported to be best described by an exponential function of the type, Iexcess = Ir0 + K1exp(K2 V, where Ir0, K1 and K2 are fitting parameters and V is the applied bias voltage. The present investigations suggest that the exponential growth of excess current with the applied bias voltage may be taking place along the localized regions in the diode. These localized regions are the shunt resistance paths on account of the surface leakage currents and/or defects and dislocations in the base of the diode.

An efficient fast response and high-gain solar-blind flexible ultraviolet photodetector employing hybrid geometry

Science.gov (United States)

Hussain, Amreen A.; Pal, Arup R.; Patil, Dinkar S.

2014-05-01

We report high performance flexible hybrid ultraviolet photodetector with solar-blind sensitivity using nanocomposite film of plasma polymerized aniline-titanium dioxide. A facile solvent-free plasma technique is used to synthesize superior quality hybrid material with high yield. The hybrid photodetector exhibited high photoconductive gain of the order of ˜105 and fast speed with response and recovery time of 22.87 ms and 34.23 ms. This is an excellent result towards getting a balance in the response speed and photoconductive gain trade-off of the photodetectors reported so far. In addition, the device has the advantages of enhanced photosensitivity ((Ilight - Idark)/Idark) of the order of ˜102 and high responsivity of ˜104 AW-1. All the merits substantiates that, to prepare hybrid material, plasma based method holds potential to be an easy way for realizing large scale nanostructured photodetectors for practical applications.

Spectrally resolved, broadband frequency response characterization of photodetectors using continuous-wave supercontinuum sources

Science.gov (United States)

Choudhury, Vishal; Prakash, Roopa; Nagarjun, K. P.; Supradeepa, V. R.

2018-02-01

A simple and powerful method using continuous wave supercontinuum lasers is demonstrated to perform spectrally resolved, broadband frequency response characterization of photodetectors in the NIR Band. In contrast to existing techniques, this method allows for a simple system to achieve the goal, requiring just a standard continuous wave(CW) high-power fiber laser source and an RF spectrum analyzer. From our recent work, we summarize methods to easily convert any high-power fiber laser into a CW supercontinuum. These sources in the time domain exhibit interesting properties all the way down to the femtosecond time scale. This enables measurement of broadband frequency response of photodetectors while the wide optical spectrum of the supercontinuum can be spectrally filtered to obtain this information in a spectrally resolved fashion. The method involves looking at the RF spectrum of the output of a photodetector under test when incident with the supercontinuum. By using prior knowledge of the RF spectrum of the source, the frequency response can be calculated. We utilize two techniques for calibration of the source spectrum, one using a prior measurement and the other relying on a fitted model. Here, we characterize multiple photodetectors from 150MHz bandwidth to >20GHz bandwidth at multiple bands in the NIR region. We utilize a supercontinuum source spanning over 700nm bandwidth from 1300nm to 2000nm. For spectrally resolved measurement, we utilize multiple wavelength bands such as around 1400nm and 1600nm. Interesting behavior was observed in the frequency response of the photodetectors when comparing broadband spectral excitation versus narrower band excitation.

TH-C-19A-10: Systematic Evaluation of Photodetectors Performances for Plastic Scintillation Dosimetry

International Nuclear Information System (INIS)

Boivin, J; Beaulieu, L; Beddar, S; Guillemette, M

2014-01-01

Purpose: To assess and compare the performance of different photodetectors likely to be used in a plastic scintillation detector (PSD). Methods: The PSD consists of a 1 mm diameter, 10 mm long plastic scintillation fiber (BCF-60) which is optically coupled to a clear 10 m long optical fiber of the same diameter. A light-tight plastic sheath covers both fibers and the scintillator end is sealed. The clear fiber end is connected to one of the following six studied photodetectors: two polychromatic cameras (one with an optical lens and one with a fiber optic taper replacing the lens); a monochromatic camera with the same optical lens; a PIN photodiode; an avalanche photodiode (APD); and a photomultiplier tube (PMT). Each PSD is exposed to both low energy beams (120, 180, and 220 kVp) from an orthovoltage unit, and high energy beams (6 MV and 23 MV) from a linear accelerator. Various dose rates are explored to identify the photodetectors operating ranges and accuracy. Results: For all photodetectors, the relative uncertainty remains under 5 % for dose rates over 3 mGy/s. The taper camera collects four times more signal than the optical lens camera, although its standard deviation is higher since it could not be cooled. The PIN, APD and PMT have higher sensitivity, suitable for low dose rate and out-of-field dose monitoring. PMT's relative uncertainty remains under 1 % at the lowest dose rate achievable (50 μGy/s), suggesting optimal use for live dosimetry. Conclusion: A set of 6 photodetectors have been studied over a broad dose rate range at various energies. For dose rate above 3 mGy/s, the PIN diode is the most effective photodetector in term of performance/cost ratio. For lower dose rate, such as those seen in interventional radiology, PMTs are the optimal choice. FQRNT Doctoral Research Scholarship

Visible Discrimination of Broadband Infrared Light by Dye-Enhanced Upconversion in Lanthanide-Doped Nanocrystals

Directory of Open Access Journals (Sweden)

Charles G. Dupuy

2014-01-01

Full Text Available Optical upconversion of near infrared light to visible light is an attractive way to capture the optical energy or optical information contained in low-energy photons that is otherwise lost to the human eye or to certain photodetectors and solar cells. Until the recent application of broadband absorbing optical antennas, upconversion efficiency in lanthanide-doped nanocrystals was limited by the weak, narrow atomic absorption of a handful of sensitizer elements. In this work, we extend the role of the optical antenna to provide false-color, visible discrimination between bands of infrared radiation. By pairing different optical antenna dyes to specific nanoparticle compositions, unique visible emission is associated with different bands of infrared excitation. In one material set, the peak emission was increased 10-fold, and the width of the spectral response was increased more than 10-fold.

Photo-Detectors Integrated with Resonant Tunneling Diodes

Directory of Open Access Journals (Sweden)

José M. L. Figueiredo

2013-07-01

Full Text Available We report on photo-detectors consisting of an optical waveguide that incorporates a resonant tunneling diode (RTD. Operating at wavelengths around 1.55 μm in the optical communications C band we achieve maximum sensitivities of around 0.29 A/W which is dependent on the bias voltage. This is due to the nature of RTD nonlinear current-voltage characteristic that has a negative differential resistance (NDR region. The resonant tunneling diode photo-detector (RTD-PD can be operated in either non-oscillating or oscillating regimes depending on the bias voltage quiescent point. The oscillating regime is apparent when the RTD-PD is biased in the NDR region giving rise to electrical gain and microwave self-sustained oscillations Taking advantage of the RTD’s NDR distinctive characteristics, we demonstrate efficient detection of gigahertz (GHz modulated optical carriers and optical control of a RTD GHz oscillator. RTD-PD based devices can have applications in generation and optical control of GHz low-phase noise oscillators, clock recovery systems, and fiber optic enabled radio frequency communication systems.

High performance organic ultraviolet photodetectors based on m-MTDATA

Science.gov (United States)

Zhao, Zhongli; Bai, Xiaofeng; Shang, Yubin; Yang, Jikai; Li, Baozeng; Song, De

2018-02-01

We demonstrate highly efficient organic ultraviolet photodetectors using 4,4',4'' -tris[3-methyl-pheny(phenyl) amino] triphenylamine (m-MTDATA) and aluminum Tris(8-Hydroxyquinolinate) Synonym Alq3). The optimized photodetector delivers a photocurrent of 1.40 mA/cm2 at10 V, corresponding to a response of 127 mA/W under an illumination of 375 nm UV light irradiation with an intensity of 10.5 mW/cm2 and a detectivity of 2.15×1011 cm Hz1/2 /W. The high response is attributed to the larger band offset at m-MTDATA/ Alq3 heterojunction, the suppression of radiative decay of m-MTDATA and efficient electron transfer from m-MTDATA to Alq3. The working mechanism of harvesting high performance is also discussed in detail.

III-N Wide Bandgap Deep-Ultraviolet Lasers and Photodetectors

KAUST Repository

Detchprohm, T.

2016-11-05

The III-N wide-bandgap alloys in the AlInGaN system have many important and unique electrical and optical properties which have been exploited to develop deep-ultraviolet (DUV) optical devices operating at wavelengths < 300 nm, including light-emitting diodes, optically pumped lasers, and photodetectors. In this chapter, we review some aspects of the development and current state of the art of these DUV materials and devices. We describe the growth of III-N materials in the UV region by metalorganic chemical vapor deposition as well as the properties of epitaxial layers and heterostructure devices. In addition, we discuss the simulation and design of DUV laser diodes, the processing of III-N optical devices, and the description of the current state of the art of DUV lasers and photodetectors.

Adaptive photodetectors for vibration monitoring

International Nuclear Information System (INIS)

Sokolov, I.A.

2003-01-01

We present characteristics of laser vibrometer using semiconductor GaAs and molecular SnS 2 adaptive photodetectors (AP) based on the effect of the non-steady-state photoelectromotive force. AP enable efficient direct conversion of high-frequency phase modulation of speckle-like optical wave reflected from the vibrating object into an output electrical signal with concomitant setting of optimal operation point of the interferometer and suppression of amplitude laser noise. The sensitivity of the setup is analyzed and further improvements in operation of AP are discussed

High-Performance Ultraviolet-to-Infrared Broadband Perovskite Photodetectors Achieved via Inter-/Intraband Transitions

KAUST Repository

Alwadai, Norah Mohammed Mosfer; Haque, Mohammed; Mitra, Somak; Flemban, Tahani H.; Pak, Yusin; Wu, Tao; Roqan, Iman S.

2017-01-01

range, from ultraviolet to infrared light region (λ = 250–1357 nm). Such structure leads to a high photoresponsivity of 28 and 0.22 A/W, for white light and IR illumination, respectively, with high detectivity values of 1.1 × 1012 and 9.3 × 109 Jones

Graphite/ZnO nanorods junction for ultraviolet photodetectors

Czech Academy of Sciences Publication Activity Database

Yatskiv, Roman; Grym, Jan; Verde, Maria

2015-01-01

Roč. 105, March 2015 (2015), s. 70-73 ISSN 0038-1101 R&D Projects: GA MŠk(CZ) LD14111 Institutional support: RVO:67985882 Keywords : ZnO nanorods * Graphite based junction * UV photodetector Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.345, year: 2015

Fabrication of Au nanoparticle/double-walled carbon nanotube film/TiO{sub 2} nanotube array/Ti heterojunctions with low resistance state for broadband photodetectors

Energy Technology Data Exchange (ETDEWEB)

Chen, Yan [School of Mathematics and Physics, Mianyang Teachers’ College (Mianyang Normal University), Mianyang 621000 (China); Zhang, Guowei; Dong, Zhanmin [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Wei, Jinquan [Key Laboratory for Advanced Materials Processing Technology of Education Ministry, School of Materials Science and Engineering, Tsinghua University, Beijing100084 (China); Zhu, Jia-Lin [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Sun, Jia-Lin, E-mail: jlsun@tsinghua.edu.cn [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

2017-03-01

A broadband photodetector based on Au nanoparticle/double-walled carbon nanotube film/TiO{sub 2} nanotube array /Ti multilayer heterojunction structures has been fabricated. A pre-electroforming process at a voltage bias of 35 V was used to switch the photodetector from a high resistance state to a low resistance state. At a voltage bias of 1 V under 532-nm laser illumination in air, the photoresponsivity of the device reached 15.41 mA W{sup −1}, which is enhanced by approximately 1.91 times when compared with that of device before deposition of Au nanoparticles. In addition, in a vacuum under a voltage bias of 1 V, the photoresponsivity of the device reached 23.29 mA W{sup −1} and 6.85 mA W{sup −1} at 532 nm and 1064 nm, respectively. The surface plasmon polaritons of the Au nanoparticles allowed extension of the sensitivity of the photosensitive regions into the mid-infrared range. The experimental results show that the device photoresponsivity reached 2.26 mA W{sup −1} at a voltage bias of 1 V under 10.6-µm laser illumination in air.

Ultraporous Electron-Depleted ZnO Nanoparticle Networks for Highly Sensitive Portable Visible-Blind UV Photodetectors.

Science.gov (United States)

Nasiri, Noushin; Bo, Renheng; Wang, Fan; Fu, Lan; Tricoli, Antonio

2015-08-05

A hierarchical nano- and microstructured morphology for visible-blind UV photo-detectors is developed, which provides record-high milliampere photocurrents, nanoampere dark currents, and excellent selectivity to ultralow UV light intensities. This is a significant step toward the integration of high-performance UV photodetectors in wearable devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Color selective photodetector and methods of making

Science.gov (United States)

Walker, Brian J.; Dorn, August; Bulovic, Vladimir; Bawendi, Moungi G.

2013-03-19

A photoelectric device, such as a photodetector, can include a semiconductor nanowire electrostatically associated with a J-aggregate. The J-aggregate can facilitate absorption of a desired wavelength of light, and the semiconductor nanowire can facilitate charge transport. The color of light detected by the device can be chosen by selecting a J-aggregate with a corresponding peak absorption wavelength.

ZnO UV photodetector with controllable quality factor and photosensitivity

Directory of Open Access Journals (Sweden)

L. C. Campos

2013-02-01

Full Text Available ZnO nanowires have an enormous potential for applications as ultra-violet (UV photodetectors. Their mechanism of photocurrent generation is intimately related with the presence of surface states where considerable efforts, such as surface chemical modifications, have been pursued to improve their photodetection capabilities. In this work, we report a step further in this direction demonstrating that the relative photosensitivity and quality factor (Q factor of the photodetector are entirely tunable by an applied gate voltage. This mechanism enables UV photodetection selectivity ranging from wavelengths from tens of nanometers (full width at half maximum - FWHM down to a narrow detection of 3 nm. Such control paves the way for novel applications, especially related to the detection of elements that have very sharp luminescence.

Highly spectrum-selective ultraviolet photodetector based on p-NiO/n-IGZO thin film heterojunction structure.

Science.gov (United States)

Li, H K; Chen, T P; Hu, S G; Li, X D; Liu, Y; Lee, P S; Wang, X P; Li, H Y; Lo, G Q

2015-10-19

Ultraviolet photodetector with p-n heterojunction is fabricated by magnetron sputtering deposition of n-type indium gallium zinc oxide (n-IGZO) and p-type nickel oxide (p-NiO) thin films on ITO glass. The performance of the photodetector is largely affected by the conductivity of the p-NiO thin film, which can be controlled by varying the oxygen partial pressure during the deposition of the p-NiO thin film. A highly spectrum-selective ultraviolet photodetector has been achieved with the p-NiO layer with a high conductivity. The results can be explained in terms of the "optically-filtering" function of the NiO layer.

Mobile In Vivo Infrared Data Collection and Diagnoses Comparison System

Science.gov (United States)

Mintz, Frederick W. (Inventor); Moynihan, Philip I. (Inventor); Gunapala, Sarath D. (Inventor)

2013-01-01

Described is a mobile in vivo infrared brain scan and analysis system. The system includes a data collection subsystem and a data analysis subsystem. The data collection subsystem is a helmet with a plurality of infrared (IR) thermometer probes. Each of the IR thermometer probes includes an IR photodetector capable of detecting IR radiation generated by evoked potentials within a user's skull. The helmet is formed to collect brain data that is reflective of firing neurons in a mobile subject and transmit the brain data to the data analysis subsystem. The data analysis subsystem is configured to generate and display a three-dimensional image that depicts a location of the firing neurons. The data analysis subsystem is also configured to compare the brain data against a library of brain data to detect an anomaly in the brain data, and notify a user of any detected anomaly in the brain data.

Bottom-Up Tri-gate Transistors and Submicrosecond Photodetectors from Guided CdS Nanowalls.

Science.gov (United States)

Xu, Jinyou; Oksenberg, Eitan; Popovitz-Biro, Ronit; Rechav, Katya; Joselevich, Ernesto

2017-11-08

Tri-gate transistors offer better performance than planar transistors by exerting additional gate control over a channel from two lateral sides of semiconductor nanowalls (or "fins"). Here we report the bottom-up assembly of aligned CdS nanowalls by a simultaneous combination of horizontal catalytic vapor-liquid-solid growth and vertical facet-selective noncatalytic vapor-solid growth and their parallel integration into tri-gate transistors and photodetectors at wafer scale (cm 2 ) without postgrowth transfer or alignment steps. These tri-gate transistors act as enhancement-mode transistors with an on/off current ratio on the order of 10 8 , 4 orders of magnitude higher than the best results ever reported for planar enhancement-mode CdS transistors. The response time of the photodetector is reduced to the submicrosecond level, 1 order of magnitude shorter than the best results ever reported for photodetectors made of bottom-up semiconductor nanostructures. Guided semiconductor nanowalls open new opportunities for high-performance 3D nanodevices assembled from the bottom up.

Application of Metamaterials to RF Energy Harvesting and Infrared Photodetection

Science.gov (United States)

Fowler, Clayton M.

, by swapping out different metasurface and antenna designs. Using this method, the amount of power harvested by a simple dipole rectenna placed within a cavity is improved by a factor of 18 as compared to what it would harvest by itself at an ambient intensity of 35 nW/cm2. Lastly, the addition of plasmonic structures to DWELL (quantum dot-in-a-well) infrared photodetectors is investigated by computer simulation. DWELL photodetectors have the potential to one day replace standard mercury cadmium telluride detectors by being cheaper alternatives with a higher operating temperature. The inclusion of gold plasmonic structure arrays into DWELL detectors enables excitation of surface plasmon polariton modes that increase the responsivity of the detector to incident infrared radiation. The peak responsivity of a DWELL detector is demonstrated to improve by a factor of 8 for a 1 mum thick layer of plasmonic structures and by a factor of 15 for a 2 mum thick layer. These works are steps forward in making RF energy harvesting practically useful and for improving infrared photodetector performance.

III-N Wide Bandgap Deep-Ultraviolet Lasers and Photodetectors

KAUST Repository

Detchprohm, T.; Li, Xiaohang; Shen, S.-C.; Yoder, P.D.; Dupuis, R.D.

2016-01-01

-emitting diodes, optically pumped lasers, and photodetectors. In this chapter, we review some aspects of the development and current state of the art of these DUV materials and devices. We describe the growth of III-N materials in the UV region by metalorganic

All-Si photodetector for telecommunication wavelength based on subwavelength grating structure and critical coupling

DEFF Research Database (Denmark)

Taghizadeh, Alireza; Rasoulzadeh Zali, Aref; Chung, Il-Sug

2017-01-01

We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered subwavelen......We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered...

Synergistic Effect of Hybrid Multilayer In2Se3 and Nanodiamonds for Highly Sensitive Photodetectors.

Science.gov (United States)

Zheng, Zhaoqiang; Yao, Jiandong; Xiao, Jun; Yang, Guowei

2016-08-10

Layered materials have rapidly established themselves as intriguing building blocks for next-generation photodetection platforms in view of their exotic electronic and optical attributes. However, both relatively low mobility and heavier electron effective mass limit layered materials for high-performance applications. Herein, we employed nanodiamonds (NDs) to promote the performance of multilayer In2Se3 photodetectors for the first time. This hybrid NDs-In2Se3 photodetector showed a tremendous promotion of photodetection performance in comparison to pristine In2Se3 ones. This hybrid devices exhibited remarkable detectivity (5.12 × 10(12) jones), fast response speed (less than 16.6 ms), and decent current on/off ratio (∼2285) simultaneously. These parameters are superior to most reported layered materials based photodetectors and even comparable to the state-of-the-art commercial photodetectors. Meanwhile, we attributed this excellent performance to the synergistic effect between NDs and the In2Se3. They can greatly enhance the broad spectrum absorption and promote the injection of photoexcited carrier in NDs to In2Se3. These results actually open up a new scenario for designing and fabricating innovative optoelectronic systems.

Solution-processed nanocrystalline PbS on paper substrate with pencil traced electrodes as visible photodetector

Science.gov (United States)

Vankhade, Dhaval; Chaudhuri, Tapas K.

2018-04-01

Paper-based PbS photodetector sensitive in the visible spectrum is reported. Nanocrystalline PbS-on-paper devices are fabricated by a spin coating method on white paper (300 GSM) from a methanolic precursor solution. Photodetector cells of gap 0.2 cm and length 0.5 cm are prepared by drawing contacts by monolithic cretacolor 8B pencil. X-ray diffractometer confirmed the deposition of nanocrystalline PbS films with 14 nm crystallites. The SEM illustrated the uniform coating of nanocrystalline PbS thin films on cellulose fibres of papers having an average thickness of fibres are 10 µm. The linear J-V characteristics in dark and under illumination of light using graphite trace on nanocrystalline PbS-on-paper shows good ohmic contact. The resistivity of pencil trace is 30 Ω.cm. Spectral response measurements of photodetector reveal the excellent sensitivity from 400 to 700 nm with a peak at 550 nm. The best responsivity anddetectivity are 0.7 A/W and 1.4 × 1012 Jones respectively. These paper-based low-cost photodetectors devices have fast photoresponse and recovery without baseline deviation.

Photovoltaic cells and photodetectors made with semiconductor polymers: recent progress

Science.gov (United States)

Yu, Gang; Srdanov, Gordana; Wang, Hailiang; Cao, Yong; Heeger, Alan J.

2000-05-01

In this presentation, we discuss recent progress on polymer photovoltaic cells and polymer photodetectors. By improving the fill-factor of polymer photovoltaic cells, the energy conversion efficiency was improved significantly to over 4 percent. Such high efficiency polymer photovoltaic cells are promising for many applications including e-papers, e-books and smart-windows. Polymer photodetectors with similar device configuration show high photosensitivity, low dark current, large dynamic range, linear intensity dependence, low noise level and fast response time. These parameters are comparable to or even better than their inorganic counterparts. The advantages of low manufacturing cost, large detection area, and easy hybridization and integration with other electronic or optical components make them promising for a variety of applications including chemical/biomedical analysis, full-color digital image sensing and high energy radiation detection.

Annealing Time Effect on Nanostructured n-ZnO/p-Si Heterojunction Photodetector Performance

Science.gov (United States)

Habubi, Nadir. F.; Ismail, Raid. A.; Hamoudi, Walid K.; Abid, Hassam. R.

2015-02-01

In this work, n-ZnO/p-Si heterojunction photodetectors were prepared by drop casting of ZnO nanoparticles (NPs) on single crystal p-type silicon substrates, followed by (15-60) min; step-annealing at 600∘C. Structural, electrical, and optical properties of the ZnO NPs films deposited on quartz substrates were studied as a function of annealing time. X-ray diffraction studies showed a polycrystalline, hexagonal wurtizte nanostructured ZnO with preferential orientation along the (100) plane. Atomic force microscopy measurements showed an average ZnO grain size within the range of 75.9 nm-99.9 nm with a corresponding root mean square (RMS) surface roughness between 0.51 nm-2.16 nm. Dark and under illumination current-voltage (I-V) characteristics of the n-ZnO/p-Si heterojunction photodetectors showed an improving rectification ratio and a decreasing saturation current at longer annealing time with an ideality factor of 3 obtained at 60 min annealing time. Capacitance-voltage (C-V) characteristics of heterojunctions were investigated in order to estimate the built-in-voltage and junction type. The photodetectors, fabricated at optimum annealing time, exhibited good linearity characteristics. Maximum sensitivity was obtained when ZnO/Si heterojunctions were annealed at 60 min. Two peaks of response, located at 650 nm and 850 nm, were observed with sensitivities of 0.12-0.19 A/W and 0.18-0.39 A/W, respectively. Detectivity of the photodetectors as function of annealing time was estimated.

Au nanoparticle-decorated silicon pyramids for plasmon-enhanced hot electron near-infrared photodetection

Science.gov (United States)

Qi, Zhiyang; Zhai, Yusheng; Wen, Long; Wang, Qilong; Chen, Qin; Iqbal, Sami; Chen, Guangdian; Xu, Ji; Tu, Yan

2017-07-01

The heterojunction between metal and silicon (Si) is an attractive route to extend the response of Si-based photodiodes into the near-infrared (NIR) region, so-called Schottky barrier diodes. Photons absorbed into a metallic nanostructure excite the surface plasmon resonances (SPRs), which can be damped non-radiatively through the creation of hot electrons. Unfortunately, the quantum efficiency of hot electron detectors remains low due to low optical absorption and poor electron injection efficiency. In this study, we propose an efficient and low-cost plasmonic hot electron NIR photodetector based on a Au nanoparticle (Au NP)-decorated Si pyramid Schottky junction. The large-area and lithography-free photodetector is realized by using an anisotropic chemical wet etching and rapid thermal annealing (RTA) of a thin Au film. We experimentally demonstrate that these hot electron detectors have broad photoresponsivity spectra in the NIR region of 1200-1475 nm, with a low dark current on the order of 10-5 A cm-2. The observed responsivities enable these devices to be competitive with other reported Si-based NIR hot electron photodetectors using perfectly periodic nanostructures. The improved performance is attributed to the pyramid surface which can enhance light trapping and the localized electric field, and the nano-sized Au NPs which are beneficial for the tunneling of hot electrons. The simple and large-area preparation processes make them suitable for large-scale thermophotovoltaic cell and low-cost NIR detection applications.

Broad Detection Range Rhenium Diselenide Photodetector Enhanced by (3-Aminopropyl)Triethoxysilane and Triphenylphosphine Treatment.

Science.gov (United States)

Jo, Seo-Hyeon; Park, Hyung-Youl; Kang, Dong-Ho; Shim, Jaewoo; Jeon, Jaeho; Choi, Seunghyuk; Kim, Minwoo; Park, Yongkook; Lee, Jaehyeong; Song, Young Jae; Lee, Sungjoo; Park, Jin-Hong

2016-08-01

The effects of triphenylphosphine and (3-aminopropyl)triethoxysilane on a rhenium diselenide (ReSe2 ) photodetector are systematically studied by comparing with conventional MoS2 devices. This study demonstrates a very high performance ReSe2 photodetector with high photoresponsivity (1.18 × 10(6) A W(-1) ), fast photoswitching speed (rising/decaying time: 58/263 ms), and broad photodetection range (possible above 1064 nm). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capacitively coupled pickup in MCP-based photodetectors using a conductive metallic anode

Energy Technology Data Exchange (ETDEWEB)

Angelico, E.; Seiss, T. [Enrico Fermi Institute, University of Chicago, 5640 S Ellis Ave, Chicago, IL 60637 (United States); Adams, B. [Incom, Inc., 294 SouthBridge Rd, Charlton, Massachusetts 01507 (United States); Elagin, A.; Frisch, H.; Spieglan, E. [Enrico Fermi Institute, University of Chicago, 5640 S Ellis Ave, Chicago, IL 60637 (United States)

2017-02-21

We have designed and tested a robust 20×20 cm{sup 2} thin metal film internal anode capacitively coupled to an external array of signal pads or micro-strips for use in fast microchannel plate photodetectors. The internal anode, in this case a 10 nm-thick NiCr film deposited on a 96% pure Al{sub 2}O{sub 3} 3 mm-thick ceramic plate and connected to HV ground, provides the return path for the electron cascade charge. The multi-channel pickup array consists of a printed-circuit card or glass plate with metal signal pickups on one side and the signal ground plane on the other. The pickup can be put in close proximity to the bottom outer surface of the sealed photodetector, with no electrical connections through the photodetector hermetic vacuum package other than a single ground connection to the internal anode. Two pickup patterns were tested using a small commercial MCP-PMT as the signal source: 1) parallel 50 Ω 25-cm-long micro-strips with an analog bandwidth of 1.5 GHz, and 2) a 20×20 cm{sup 2} array of 2-dimensional square ‘pads’ with sides of 1.27 cm or 2.54 cm. The rise-time of the fast input pulse is maintained for both pickup patterns. For the pad pattern, we observe 80% of the directly coupled amplitude. For the strip pattern we measure 34% of the directly coupled amplitude on the central strip of a broadened signal. The physical decoupling of the photodetector from the pickup pattern allows easy customization for different applications while maintaining high analog bandwidth.

Two-dimensional bismuth nanosheets as prospective photo-detector with tunable optoelectronic performance

Science.gov (United States)

Huang, Hao; Ren, Xiaohui; Li, Zhongjun; Wang, Huide; Huang, Zongyu; Qiao, Hui; Tang, Pinghua; Zhao, Jinlai; Liang, Weiyuan; Ge, Yanqi; Liu, Jie; Li, Jianqing; Qi, Xiang; Zhang, Han

2018-06-01

Two dimensional Bi nanosheets have been employed to fabricate electrodes for broadband photo-detection. A series of characterization techniques including scanning electron microscopy and high-resolution transmission electron microscopy have verified that Bi nanosheets with intact lamellar structure have been obtained after facile liquid phase exfoliation. In the meanwhile, UV–vis and Raman spectra are also carried out and the inherent optical and physical properties of Bi nanosheets are confirmed. Inherited from the topological characteristics of Bi bulk counterpart, the resultant Bi nanosheet-based photo-detector exhibits preferable photo-response activity as well as environmental robustness. We then evaluate the photo-electrochemical (PEC) performance of the photodetector in 1 M NaOH and 0.5 M Na2SO4 electrolytes, and demonstrated that the as-prepared Bi nanosheets may possess a great potential as PEC-type photo-detector. Additional PEC measurements show that the current density of Bi nanosheets can reach up to 830 nA cm‑2, while an enhanced responsivity (1.8 μA W‑1) had been achieved. We anticipate that this contribution can provide feasibility towards the construction of high-performance elemental Bi nanosheets-based optoelectronic devices in the future.

Highly sensitive MoS2 photodetectors with graphene contacts

Science.gov (United States)

Han, Peize; St. Marie, Luke; Wang, Qing X.; Quirk, Nicholas; El Fatimy, Abdel; Ishigami, Masahiro; Barbara, Paola

2018-05-01

Two-dimensional materials such as graphene and transition metal dichalcogenides (TMDs) are ideal candidates to create ultra-thin electronics suitable for flexible substrates. Although optoelectronic devices based on TMDs have demonstrated remarkable performance, scalability is still a significant issue. Most devices are created using techniques that are not suitable for mass production, such as mechanical exfoliation of monolayer flakes and patterning by electron-beam lithography. Here we show that large-area MoS2 grown by chemical vapor deposition and patterned by photolithography yields highly sensitive photodetectors, with record shot-noise-limited detectivities of 8.7 × 1014 Jones in ambient condition and even higher when sealed with a protective layer. These detectivity values are higher than the highest values reported for photodetectors based on exfoliated MoS2. We study MoS2 devices with gold electrodes and graphene electrodes. The devices with graphene electrodes have a tunable band alignment and are especially attractive for scalable ultra-thin flexible optoelectronics.

Role of Ga vacancies in enhancing the leakage current of GaN Schottky barrier ultraviolet photodetectors

International Nuclear Information System (INIS)

De-Gang, Zhao; Shuang, Zhang; Wen-Bao, Liu; De-Sheng, Jiang; Jian-Jun, Zhu; Zong-Shun, Liu; Hui, Wang; Shu-Ming, Zhang; Hui, Yang; Xiao-Peng, Hao; Long, Wei

2010-01-01

The leakage current of GaN Schottky barrier ultraviolet photodetectors is investigated. It is found that the photodetectors adopting undoped GaN instead of lightly Si-doped GaN as an active layer show a much lower leakage current even when they have a higher dislocation density. It is also found that the density of Ga vacancies in undoped GaN is much lower than in Si-doped GaN. The Ga vacancies may enhance tunneling and reduce effective Schottky barrier height, leading to an increase of leakage current. It suggests that when undoped GaN is used as the active layer, it is necessary to reduce the leakage current of GaN Schottky barrier ultraviolet photodetector. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Latest generation of ASICs for photodetector readout

Science.gov (United States)

Seguin-Moreau, N.

2013-08-01

The OMEGA microelectronics group has designed a new generation of multichannel integrated circuits, the "ROC" family, in AustrianMicroSystem (AMS) SiGe 0.35 μm technology to read out signals from various families of photodetectors. The chip named MAROC (standing for Multi Anode ReadOut Chip) has been designed to read out MultiAnode Photomultipliers (MAPMT), Photomultiplier ARray In SiGe ReadOut Chip (PARISROC) to read out Photomultipliers (PMTs) and SiPM Integrated ReadOut Chip (SPIROC) to readout Silicon PhotoMultiplier (SiPM) detectors and which was the first ASIC to do so. The three of them fulfill the stringent requirements of the future photodetectors, in particular in terms of low noise, radiation hardness, large dynamic range, high density and high speed while keeping low power thanks to the SiGe technology. These multi-channel ASICs are real System on Chip (SoC) as they provide charge, time and photon-counting information which are digitized internally. Their complexity and versatility enable innovative frontier detectors and also cover spin off of these detectors in adjacent fields such as medical or material imaging as well as smart detectors. In this presentation, the three ASIC architectures and test results will be described to give a general panorama of the "ROC" chips.

Latest generation of ASICs for photodetector readout

Energy Technology Data Exchange (ETDEWEB)

Seguin-Moreau, N., E-mail: seguin@lal.in2p3.fr [Laboratoire de l’Accélérateur Linéaire, IN2P3-CNRS, Université Paris-Sud, Bâtiment 200, 91898 Orsay Cedex (France)

2013-08-01

The OMEGA microelectronics group has designed a new generation of multichannel integrated circuits, the “ROC” family, in AustrianMicroSystem (AMS) SiGe 0.35 μm technology to read out signals from various families of photodetectors. The chip named MAROC (standing for Multi Anode ReadOut Chip) has been designed to read out MultiAnode Photomultipliers (MAPMT), Photomultiplier ARray In SiGe ReadOut Chip (PARISROC) to read out Photomultipliers (PMTs) and SiPM Integrated ReadOut Chip (SPIROC) to readout Silicon PhotoMultiplier (SiPM) detectors and which was the first ASIC to do so. The three of them fulfill the stringent requirements of the future photodetectors, in particular in terms of low noise, radiation hardness, large dynamic range, high density and high speed while keeping low power thanks to the SiGe technology. These multi-channel ASICs are real System on Chip (SoC) as they provide charge, time and photon-counting information which are digitized internally. Their complexity and versatility enable innovative frontier detectors and also cover spin off of these detectors in adjacent fields such as medical or material imaging as well as smart detectors. In this presentation, the three ASIC architectures and test results will be described to give a general panorama of the “ROC” chips.

Latest generation of ASICs for photodetector readout

International Nuclear Information System (INIS)

Seguin-Moreau, N.

2013-01-01

The OMEGA microelectronics group has designed a new generation of multichannel integrated circuits, the “ROC” family, in AustrianMicroSystem (AMS) SiGe 0.35 μm technology to read out signals from various families of photodetectors. The chip named MAROC (standing for Multi Anode ReadOut Chip) has been designed to read out MultiAnode Photomultipliers (MAPMT), Photomultiplier ARray In SiGe ReadOut Chip (PARISROC) to read out Photomultipliers (PMTs) and SiPM Integrated ReadOut Chip (SPIROC) to readout Silicon PhotoMultiplier (SiPM) detectors and which was the first ASIC to do so. The three of them fulfill the stringent requirements of the future photodetectors, in particular in terms of low noise, radiation hardness, large dynamic range, high density and high speed while keeping low power thanks to the SiGe technology. These multi-channel ASICs are real System on Chip (SoC) as they provide charge, time and photon-counting information which are digitized internally. Their complexity and versatility enable innovative frontier detectors and also cover spin off of these detectors in adjacent fields such as medical or material imaging as well as smart detectors. In this presentation, the three ASIC architectures and test results will be described to give a general panorama of the “ROC” chips

4th International Conference on New Photo-Detectors

CERN Document Server

2016-01-01

The purpose of this Conference is to discuss new ideas and recent developments in photo-detectors and their applications in various fields: high energy physics, neutrino physics, particle and astroparticle physics, nuclear physics, nuclear medicine and industry. The main topics of the Conference relate to APD, SiPM, PMT, Hybrid PMT, MCP-PMT, and electronics: front-end and readout of large systems.

High performance ultraviolet photodetectors based on ZnO nanoflakes/PVK heterojunction

Energy Technology Data Exchange (ETDEWEB)

Cai, Yuhua; Xiang, Jinzhong, E-mail: jzhxiang@ynu.edu.cn [School of Physical and Astronomy, Yunnan University, Kunming 650091 (China); Tang, Libin, E-mail: scitang@163.com; Ji, Rongbin, E-mail: jirongbin@gmail.com; Zhao, Jun; Kong, Jincheng [Kunming Institute of Physics, Kunming 650223 (China); Lai, Sin Ki; Lau, Shu Ping [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Zhang, Kai [Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China)

2016-08-15

A high performance ultraviolet (UV) photodetector is receiving increasing attention due to its significant applications in fire warning, environmental monitoring, scientific research, astronomical observation, etc. The enhancement in performance of the UV photodetector has been impeded by lacking of a high-efficiency heterojunction in which UV photons can efficiently convert into charges. In this work, the high performance UV photodetectors have been realized by utilizing organic/inorganic heterojunctions based on a ZnO nanoflakes/poly (N-vinylcarbazole) hybrid. A transparent conducting polymer poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate)-coated quartz substrate is employed as the anode in replacement of the commonly ITO-coated glass in order to harvest shorter UV light. The devices show a lower dark current density, with a high responsivity (R) of 7.27 × 10{sup 3 }A/W and a specific detectivity (D*) of 6.20 × 10{sup 13} cm Hz{sup 1/2}/W{sup −1} at 2 V bias voltage in ambient environment (1.30 mW/cm{sup 2} at λ = 365 nm), resulting in the enhancements in R and D* by 49% and one order of magnitude, respectively. The study sheds light on developing high-performance, large scale-array, flexible UV detectors using the solution processable method.

Zero-Power-Consumption Solar-Blind Photodetector Based on β-Ga2O3/NSTO Heterojunction.

Science.gov (United States)

Guo, Daoyou; Liu, Han; Li, Peigang; Wu, Zhenping; Wang, Shunli; Cui, Can; Li, Chaorong; Tang, Weihua

2017-01-18

A solar-blind photodetector based on β-Ga 2 O 3 /NSTO (NSTO = Nb:SrTiO 3 ) heterojunctions were fabricated for the first time, and its photoelectric properties were investigated. The device presents a typical positive rectification in the dark, while under 254 nm UV light illumination, it shows a negative rectification, which might be caused by the generation of photoinduced electron-hole pairs in the β-Ga 2 O 3 film layer. With zero bias, that is, zero power consumption, the photodetector shows a fast photoresponse time (decay time τ d = 0.07 s) and the ratio I photo /I dark ≈ 20 under 254 nm light illumination with a light intensity of 45 μW/cm 2 . Such behaviors are attributed to the separation of photogenerated electron-hole pairs driven by the built-in electric field in the depletion region of β-Ga 2 O 3 and the NSTO interface, and the subsequent transport toward corresponding electrodes. The photocurrent increases linearly with increasing the light intensity and applied bias, while the response time decreases with the increase of the light intensity. Under -10 V bias and 45 μW/cm 2 of 254 nm light illumination, the photodetector exhibits a responsivity R λ of 43.31 A/W and an external quantum efficiency of 2.1 × 10 4 %. The photo-to-electric conversion mechanism in the β-Ga 2 O 3 /NSTO heterojunction photodetector is explained in detail by energy band diagrams. The results strongly suggest that a photodetector based on β-Ga 2 O 3 thin-film heterojunction structure can be practically used to detect weak solar-blind signals because of its high photoconductive gain.

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

Energy Technology Data Exchange (ETDEWEB)

Starkenburg, Daken J. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA; Johns, Paul M. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611, USA; Detection Systems Group, Pacific Northwest National Laboratory, Richland, Washington 99354, USA; Baciak, James E. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA; Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611, USA; Nino, Juan C. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA; Xue, Jiangeng [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA

2017-12-14

Developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced from an X-ray generator, SubPc:C60, AlPcCl:C70, and P3HT:PC61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.28 µGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy-1 cm-2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

Science.gov (United States)

Starkenburg, Daken J.; Johns, Paul M.; Baciak, James E.; Nino, Juan C.; Xue, Jiangeng

2017-12-01

Developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced from an X-ray generator, SubPc:C60, AlPcCl:C70, and P3HT:PC61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.18 μGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy-1 cm-2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.

Infrared to visible image up-conversion using optically addressed spatial light modulator utilizing liquid crystal and InGaAs photodiodes

Energy Technology Data Exchange (ETDEWEB)

Solodar, A., E-mail: asisolodar@gmail.com; Arun Kumar, T.; Sarusi, G.; Abdulhalim, I. [Department of Electro-Optics Engineering and The Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)

2016-01-11

Combination of InGaAs/InP heterojunction photodetector with nematic liquid crystal (LC) as the electro-optic modulating material for optically addressed spatial light modulator for short wavelength infra-red (SWIR) to visible light image conversion was designed, fabricated, and tested. The photodetector layer is composed of 640 × 512 photodiodes array based on heterojunction InP/InGaAs having 15 μm pitch on InP substrate and with backside illumination architecture. The photodiodes exhibit extremely low, dark current at room temperature, with optimum photo-response in the SWIR region. The photocurrent generated in the heterojunction, due to the SWIR photons absorption, is drifted to the surface of the InP, thus modulating the electric field distribution which modifies the orientation of the LC molecules. This device can be attractive for SWIR to visible image upconversion, such as for uncooled night vision goggles under low ambient light conditions.

An Enhanced UV-Vis-NIR an d Flexible Photodetector Based on Electrospun ZnO Nanowire Array/PbS Quantum Dots Film Heterostructure.

Science.gov (United States)

Zheng, Zhi; Gan, Lin; Zhang, Jianbing; Zhuge, Fuwei; Zhai, Tianyou

2017-03-01

ZnO nanostructure-based photodetectors have a wide applications in many aspects, however, the response range of which are mainly restricted in the UV region dictated by its bandgap. Herein, UV-vis-NIR sensitive ZnO photodetectors consisting of ZnO nanowires (NW) array/PbS quantum dots (QDs) heterostructures are fabricated through modified electrospining method and an exchanging process. Besides wider response region compared to pure ZnO NWs based photodetectors, the heterostructures based photodetectors have faster response and recovery speed in UV range. Moreover, such photodetectors demonstrate good flexibility as well, which maintain almost constant performances under extreme (up to 180°) and repeat (up to 200 cycles) bending conditions in UV-vis-NIR range. Finally, this strategy is further verified on other kinds of 1D nanowires and 0D QDs, and similar enhancement on the performance of corresponding photodetecetors can be acquired, evidencing the universality of this strategy.

Highly sensitive and area-efficient CMOS image sensor using a PMOSFET-type photodetector with a built-in transfer gate

Science.gov (United States)

Seo, Sang-Ho; Kim, Kyoung-Do; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

2007-02-01

In this paper, a new CMOS image sensor is presented, which uses a PMOSFET-type photodetector with a transfer gate that has a high and variable sensitivity. The proposed CMOS image sensor has been fabricated using a 0.35 μm 2-poly 4- metal standard CMOS technology and is composed of a 256 × 256 array of 7.05 × 7.10 μm pixels. The unit pixel has a configuration of a pseudo 3-transistor active pixel sensor (APS) with the PMOSFET-type photodetector with a transfer gate, which has a function of conventional 4-transistor APS. The generated photocurrent is controlled by the transfer gate of the PMOSFET-type photodetector. The maximum responsivity of the photodetector is larger than 1.0 × 10 3 A/W without any optical lens. Fabricated 256 × 256 CMOS image sensor exhibits a good response to low-level illumination as low as 5 lux.

Phase-Engineered Type-II Multimetal-Selenide Heterostructures toward Low-Power Consumption, Flexible, Transparent, and Wide-Spectrum Photoresponse Photodetectors.

Science.gov (United States)

Chen, Yu-Ze; Wang, Sheng-Wen; Su, Teng-Yu; Lee, Shao-Hsin; Chen, Chia-Wei; Yang, Chen-Hua; Wang, Kuangye; Kuo, Hao-Chung; Chueh, Yu-Lun

2018-05-01

Phase-engineered type-II metal-selenide heterostructures are demonstrated by directly selenizing indium-tin oxide to form multimetal selenides in a single step. The utilization of a plasma system to assist the selenization facilitates a low-temperature process, which results in large-area films with high uniformity. Compared to single-metal-selenide-based photodetectors, the multimetal-selenide photodetectors exhibit obviously improved performance, which can be attributed to the Schottky contact at the interface for tuning the carrier transport, as well as the type-II heterostructure that is beneficial for the separation of the electron-hole pairs. The multimetal-selenide photodetectors exhibit a response to light over a broad spectrum from UV to visible light with a high responsivity of 0.8 A W -1 and an on/off current ratio of up to 10 2 . Interestingly, all-transparent photodetectors are successfully produced in this work. Moreover, the possibility of fabricating devices on flexible substrates is also demonstrated with sustainable performance, high strain tolerance, and high durability during bending tests. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantum efficiency investigations of type-II InAs/GaSb midwave infrared superlattice photodetectors

Energy Technology Data Exchange (ETDEWEB)

Giard, E., E-mail: edouard.giard@onera.fr; Ribet-Mohamed, I.; Jaeck, J.; Viale, T.; Haïdar, R. [ONERA, DOTA, Chemin de la Hunière, 91761 Palaiseau Cedex (France); Taalat, R.; Delmas, M.; Rodriguez, J.-B.; Christol, P. [Institut d' Electronique du Sud, UMR-CNRS 5214, Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Steveler, E.; Bardou, N. [Laboratoire de Photonique et de Nanostructures (LPN-CNRS), Route de Nozay, 91460 Marcoussis (France); Boulard, F. [CEA, LETI, MINATEC Campus, 17 Avenue des martyrs, 38054 Grenoble (France)

2014-07-28

We present in this paper a comparison between different type-II InAs/GaSb superlattice (T2SL) photodiodes and focal plane array (FPA) in the mid-wavelength infrared domain to understand which phenomenon drives the performances of the T2SL structure in terms of quantum efficiency (QE). Our measurements on test photodiodes suggest low minority carrier diffusion length in the “InAs-rich” design, which penalizes carriers' collection in this structure for low bias voltage and front side illumination. This analysis is completed by a comparison of the experimental data with a fully analytic model, which allows to infer a hole diffusion length shorter than 100 nm. In addition, measurements on a FPA with backside illumination are finally presented. Results show an average QE in the 3–4.7 μm window equal to 42% for U{sub bias} = −0.1 V, 77 K operating temperature and no anti-reflection coating. These measurements, completed by modulation transfer function and noise measurements, reveal that the InAs-rich design, despite a low hole diffusion length, is promising for high performance infrared imaging applications.

A high-sensitive ultraviolet photodetector composed of double-layered TiO{sub 2} nanostructure and Au nanoparticles film based on Schottky junction

Energy Technology Data Exchange (ETDEWEB)

Wang, Huan; Qin, Pei [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Yi, Guobin, E-mail: ygb702@163.com [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Zu, Xihong [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Zhang, Li, E-mail: zhangli2368@126.com [School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006 (China); Hong, Wei; Chen, Xudong [School of Chemistry and Chemical Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, 510275 (China)

2017-06-15

In this study, a Schottky-type ultraviolet (UV) photodetector based on double-layered nanostructured TiO{sub 2}/Au films was fabricated. Double-layered titanium dioxide (TiO{sub 2}) nanostructures composed of one layer of TiO{sub 2} nano-flowers on one layer of TiO{sub 2} nanorods on fluorine-doped tin oxide (FTO) pre-coated glass substrates were synthesized via a convenient hydrothermal method using titanium butoxide and hydrochloric acid as the starting precursor, without involving the use of any other surfactants and catalysts. A granular-shaped thin-layer of Au film using vacuum sputter coating technique was subsequently deposited on TiO{sub 2} for the formation of Schottky-type photodetector. The as-fabricated Schottky device showed various photocurrent responses when irradiated with different wavelength of UV light. This suggests that the newly-developed photodetectors have promising potential for identifying different UV light wavelengths. - Highlights: • A novel double-layered TiO{sub 2} nanostructure was synthesized by a simple method. • An UV photodetector composed of TiO{sub 2} and Au was designed and fabricated. • The preparation method of TiO{sub 2}/Au UV photodetector was simple and convenient. • The UV photodetector based on TiO{sub 2}/Au showed excellent sensitivity to UV light.

Tunable optical coherence tomography in the infrared range using visible photons

Science.gov (United States)

Paterova, Anna V.; Yang, Hongzhi; An, Chengwu; Kalashnikov, Dmitry A.; Krivitsky, Leonid A.

2018-04-01

Optical coherence tomography (OCT) is an appealing technique for bio-imaging, medicine, and material analysis. For many applications, OCT in mid- and far-infrared (IR) leads to significantly more accurate results. Reported mid-IR OCT systems require light sources and photodetectors which operate in mid-IR range. These devices are expensive and need cryogenic cooling. Here, we report a proof-of-concept demonstration of a wavelength tunable IR OCT technique with detection of only visible range photons. Our method is based on the nonlinear interference of frequency correlated photon pairs. The nonlinear crystal, introduced in the Michelson-type interferometer, generates photon pairs with one photon in the visible and another in the IR range. The intensity of detected visible photons depends on the phase and loss of IR photons, which interact with the sample under study. This enables us to characterize sample properties and perform imaging in the IR range by detecting visible photons. The technique possesses broad wavelength tunability and yields a fair axial and lateral resolution, which can be tailored to the specific application. The work contributes to the development of versatile 3D imaging and material characterization systems working in a broad range of IR wavelengths, which do not require the use of IR-range light sources and photodetectors.

Robust and Air-Stable Sandwiched Organo-Lead Halide Perovskites for Photodetector Applications

KAUST Repository

Mohammed, Omar F.; Banavoth, Murali; Saidaminov, Makhsud I.; Abdelhady, Ahmed L.; Pan, Jun; Liu, Jiakai; Peng, Wei; Bakr, Osman

2016-01-01

We report the simplest possible method to date for fabricating robust, air-stable, sandwiched perovskite photodetectors. Our proposed sandwiched structure is devoid of electron or hole transporting layers and also the expensive electrodes

Low-cost near-infrared measurement of subcutaneous fat for newborn malnutrition

Science.gov (United States)

McEwan, A. L.; Bian, S.; Gargiulo, G. D.; Morhard, R.; Jones, P.; Mustafa, F. H.; Bek, B. Emily; Jeffery, H. E.

2014-04-01

Low fat composition in newborns exposes them to an immediate risk of increased mortality and morbidity, inhibited physical and cognitive development and to diabetes and obesity diseases in later life. Information about nutritional and dietary status of newborns can be accessed by measuring the amount of fat composition in the body. The functions of subcutaneous fat involve energy storage, thermo-insulation and a physical buffer. Current technologies for newborn body fat monitoring are: a device based on air displacement plethesmography (PeaPod), dual-energy Xray, and underwater weighting. However they are bulky, expensive, immobile, and require technical expertise. We propose an alternative portable measurement system of in-vitro for subcutaneous fat that uses diffuse near-infrared light reflectance measurement system. We also introduce an in-vitro three-layered tissue model mimicking the subcutaneous fat layer in newborns together with a preliminary study to measure fat using dual-wavelength nearinfrared light. Based on the output data from these measurements, we have proposed a suitable transmission and scattering model. This model estimated the amount of reflected light collected by a photodetector after incident light is scattered in several fat layers. Our portable sensor is low cost and does not require training hence it is suitable for mass use in the developing world. It consists of a single LED and two photodetectors (900 nm and 1000 nm). The photodetectors wavelengths were chosen to be sensitive to fat as it exhibits a peak in the wavelength at 930 nm and to water at which exhibits a peak at 980 nm; the latter is used, to remove hydration bias. Results on a porcine tissue model demonstrate differentiation as low as 2 mm fat which is a relevant screening thickness to indicate low percentage body fat.

Photocurrent enhancement of graphene photodetectors by photon tunneling of light into surface plasmons

Science.gov (United States)

Maleki, Alireza; Cumming, Benjamin P.; Gu, Min; Downes, James E.; Coutts, David W.; Dawes, Judith M.

2017-10-01

We demonstrate that surface plasmon resonances excited by photon tunneling through an adjacent dielectric medium enhance the photocurrent detected by a graphene photodetector. The device is created by overlaying a graphene sheet over an etched gap in a gold film deposited on glass. The detected photocurrents are compared for five different excitation wavelengths, ranging from {λ }0=570 {{nm}} to {λ }0=730 {{nm}}. Although the device is not optimized, the photocurrent excited with incident p-polarized light (which excites resonant surface plasmons) is significantly amplified in comparison with that for s-polarized light (without surface plasmon resonances). We observe that the photocurrent is greater for shorter wavelengths (for both s- and p-polarizations) with increased photothermal current. Position-dependent Raman spectroscopic analysis of the optically-excited graphene photodetector indicates the presence of charge carriers in the graphene near the metallic edge. In addition, we show that the polarity of the photocurrent reverses across the gap as the incident light spot moves across the gap. Graphene-based photodetectors offer a simple architecture which can be fabricated on dielectric waveguides to exploit the plasmonic photocurrent enhancement of the evanescent field. Applications for these devices include photodetection, optical sensing and direct plasmonic detection.

Semi-insulating GaAs and Au Schottky barrier photodetectors for near-infrared detection (1280 nm)

Science.gov (United States)

Nusir, A. I.; Makableh, Y. F.; Manasreh, O.

2015-08-01

Schottky barriers formed between metal (Au) and semiconductor (GaAs) can be used to detect photons with energy lower than the bandgap of the semiconductor. In this study, photodetectors based on Schottky barriers were fabricated and characterized for the detection of light at wavelength of 1280 nm. The device structure consists of three gold fingers with 1.75 mm long and separated by 0.95 mm, creating an E shape while the middle finger is disconnected from the outer frame. When the device is biased, electric field is stretched between the middle finger and the two outermost electrodes. The device was characterized by measuring the current-voltage (I-V) curve at room temperature. This showed low dark current on the order of 10-10 A, while the photocurrent was higher than the dark current by four orders of magnitude. The detectivity of the device at room temperature was extracted from the I-V curve and estimated to be on the order of 5.3x1010 cm.Hz0.5/W at 5 V. The step response of the device was measured from time-resolved photocurrent curve at 5 V bias with multiple on/off cycles. From which the average recovery time was estimated to be 0.63 second when the photocurrent decreases by four orders of magnitude, and the average rise time was measured to be 0.897 second. Furthermore, the spectral response spectrum of the device exhibits a strong peak close to the optical communication wavelength (~1.3 μm), which is attributed to the internal photoemission of electrons above the Schottky barrier formed between Au and GaAs.

State-of-the-art photodetectors for optoelectronic integration at telecommunication wavelength

Directory of Open Access Journals (Sweden)

Eng Png Ching

2015-01-01

Full Text Available Photodetectors hold a critical position in optoelectronic integrated circuits, and they convert light into electricity. Over the past decades, high-performance photodetectors (PDs have been aggressively pursued to enable high-speed, large-bandwidth, and low-noise communication applications. Various material systems have been explored and different structures designed to improve photodetection capability as well as compatibility with CMOS circuits. In this paper, we review state-of-theart photodetection technologies in the telecommunications spectrum based on different material systems, including traditional semiconductors such as InGaAs, Si, Ge and HgCdTe, as well as recently developed systems such as low-dimensional materials (e.g. graphene, carbon nanotube, etc. and noble metal plasmons. The corresponding material properties, fundamental mechanisms, fabrication, theoretical modelling and performance of the typical PDs are presented, including the emerging directions and perspectives of the PDs for optoelectronic integration applications are discussed.

Interfacial Electronic Structures of Photodetectors Based on C8BTBT/Perovskite.

Science.gov (United States)

Li, Lin; Tong, Sichao; Zhao, Yuan; Wang, Can; Wang, Shitan; Lyu, Lu; Huang, Yingbao; Huang, Han; Yang, Junliang; Niu, Dongmei; Liu, Xiaoliang; Gao, Yongli

2018-06-07

Comprehensive measurements of ultraviolet photoemission spectroscopy, X-ray photoemission spectroscopy, X-ray diffraction, and atomic force microscopy are adopted to investigate the corelevance of energy level alignment, molecular orientation, and film growth of Au/C8BTBT/perovskite interfaces. A small energy offset of valence band maximum of 0.06 eV between perovskite and C8BTBT makes hole transportation feasible. About 0.65 eV upward shift of energy levels is observed with the deposition of the Au film on C8BTBT, which enhances hole transportation to the Au electrode. The observations from the interface analysis are supported by a prototype photodetector of Au (80 nm)/C8BTBT (20 nm)/perovskite (100 nm) that exhibits excellent performances whose responsivity can reach up to 2.65 A W -1 , 4 times higher than the best CH 3 NH 3 PbI 3 photodetectors.

Enhanced Performance of MoS2 Photodetectors by Inserting an ALD-Processed TiO2 Interlayer

KAUST Repository

Pak, Yusin

2017-12-05

2D molybdenum disulfide (MoS2) possesses excellent optoelectronic properties that make it a promising candidate for use in high-performance photodetectors. Yet, to meet the growing demand for practical and reliable MoS2 photodetectors, the critical issue of defect introduction to the interface between the exfoliated MoS2 and the electrode metal during fabrication must be addressed, because defects deteriorate the device performance. To achieve this objective, the use of an atomic layer-deposited TiO2 interlayer (between exfoliated MoS2 and electrode) is reported in this work, for the first time, to enhance the performance of MoS2 photodetectors. The TiO2 interlayer is inserted through 20 atomic layer deposition cycles before depositing the electrode metal on MoS2/SiO2 substrate, leading to significantly enhanced photoresponsivity and response speed. These results pave the way for practical applications and provide a novel direction for optimizing the interlayer material.

Enhanced Performance of MoS2 Photodetectors by Inserting an ALD-Processed TiO2 Interlayer

KAUST Repository

Pak, Yusin; Park, Woojin; Mitra, Somak; Devi, Assa Aravindh Sasikala; Loganathan, Kalaivanan; Kumaresan, Yogeenth; Kim, Yonghun; Cho, Byungjin; Jung, Gun-Young; Hussain, Muhammad Mustafa; Roqan, Iman S.

2017-01-01

2D molybdenum disulfide (MoS2) possesses excellent optoelectronic properties that make it a promising candidate for use in high-performance photodetectors. Yet, to meet the growing demand for practical and reliable MoS2 photodetectors, the critical issue of defect introduction to the interface between the exfoliated MoS2 and the electrode metal during fabrication must be addressed, because defects deteriorate the device performance. To achieve this objective, the use of an atomic layer-deposited TiO2 interlayer (between exfoliated MoS2 and electrode) is reported in this work, for the first time, to enhance the performance of MoS2 photodetectors. The TiO2 interlayer is inserted through 20 atomic layer deposition cycles before depositing the electrode metal on MoS2/SiO2 substrate, leading to significantly enhanced photoresponsivity and response speed. These results pave the way for practical applications and provide a novel direction for optimizing the interlayer material.

High-Performance Visible-Blind Ultraviolet Photodetector Based on IGZO TFT Coupled with p-n Heterojunction.

Science.gov (United States)

Yu, Jingjing; Javaid, Kashif; Liang, Lingyan; Wu, Weihua; Liang, Yu; Song, Anran; Zhang, Hongliang; Shi, Wen; Chang, Ting-Chang; Cao, Hongtao

2018-03-07

A visible-blind ultraviolet (UV) photodetector was designed based on a three-terminal electronic device of thin-film transistor (TFT) coupled with two-terminal p-n junction optoelectronic device, in hope of combining the beauties of both of the devices together. Upon the uncovered back-channel surface of amorphous indium-gallium-zinc-oxide (IGZO) TFT, we fabricated PEDOT:PSS/SnO x /IGZO heterojunction structure, through which the formation of a p-n junction and directional carrier transfer of photogenerated carriers were experimentally validated. As expected, the photoresponse characteristics of the newly designed photodetector, with a photoresponsivity of 984 A/W at a wavelength of 320 nm, a UV-visible rejection ratio up to 3.5 × 10 7 , and a specific detectivity up to 3.3 × 10 14 Jones, are not only competitive compared to the previous reports but also better than those of the pristine IGZO phototransistor. The hybrid photodetector could be operated in the off-current region with low supply voltages (<0.1 V) and ultralow power dissipation (<10 nW under illumination and ∼0.2 pW in the dark). Moreover, by applying a short positive gate pulse onto the gate, the annoying persistent photoconductivity presented in the wide band gap oxide-based devices could be suppressed conveniently, in hope of improving the response rate. With the terrific photoresponsivity along with the advantages of photodetecting pixel integration, the proposed phototransistor could be potentially used in high-performance visible-blind UV photodetector pixel arrays.

Characterization of time resolved photodetector systems for Positron Emission Tomography

CERN Document Server

Powolny, François

The main topic of this work is the study of detector systems composed of a scintillator, a photodetector and readout electronics, for Positron Emission Tomography (PET). In particular, the timing properties of such detector systems are studied. The first idea is to take advantage of the good timing properties of the NINO chip, which is a fast preamplifier-discriminator developed for the ALICE Time of flight detector at CERN. This chip uses a time over threshold technique that is to be applied for the first time in medical imaging applications. A unique feature of this technique is that it delivers both timing and energy information with a single digital pulse, the time stamp with the rising edge and the energy from the pulse width. This entails substantial simplification of the entire readout architecture of a tomograph. The scintillator chosen in the detector system is LSO. Crystals of 2x2x10mm3 were used. For the photodetector, APDs were first used, and were then replaced by SiPMs to make use of their highe...

Recovery of thermal-degraded ZnO photodetector by embedding nano silver oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hu, Zhan-Shuo [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hung, Fei-Yi, E-mail: fyhung@mail.ncku.edu.tw [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Chen, Kuan-Jen [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); The Instrument Center, National Cheng Kung University, Tainan 701, Taiwan (China); Chang, Shoou-Jinn [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Hsieh, Wei-Kang; Liao, Tsai-Yu; Chen, Tse-Pu [Institute of Microelectronics, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China)

2013-08-15

The degraded performance of annealed ZnO-based photodetector can be recovered by embedding Ag{sub 2}O nanoparticles resulted from the transformation of as-deposited Ag layer. After thermal treatment, the electrons were attracted at the interface between ZnO and Ag{sub 2}O. The excess Ag{sup +} ions form the cluster to incorporate into the interstitial sites of ZnO lattice to create a larger amount of lattice defects for the leakage path. The photo-current of ZnO film with Ag{sub 2}O nanoparticles is less than annealed ZnO film because the photo-induced electrons would flow into Ag{sub 2}O side. ZnO photodetector with the appropriate Ag{sub 2}O nanoparticles possesses the best rejection ratio.

Self-Powered Solar-Blind Photodetector with Fast Response Based on Au/β-Ga2O3 Nanowires Array Film Schottky Junction.

Science.gov (United States)

Chen, Xing; Liu, Kewei; Zhang, Zhenzhong; Wang, Chunrui; Li, Binghui; Zhao, Haifeng; Zhao, Dongxu; Shen, Dezhen

2016-02-17

Because of the direct band gap of 4.9 eV, β-Ga2O3 has been considered as an ideal material for solar-blind photodetection without any bandgap tuning. Practical applications of the photodetectors require fast response speed, high signal-to-noise ratio, low energy consumption and low fabrication cost. Unfortunately, most reported β-Ga2O3-based photodetectors usually possess a relatively long response time. In addition, the β-Ga2O3 photodetectors based on bulk, the individual 1D nanostructure, and the film often suffer from the high cost, the low repeatability, and the relatively large dark current, respectively. In this paper, a Au/β-Ga2O3 nanowires array film vertical Schottky photodiode is successfully fabricated by a simple thermal partial oxidation process. The device exhibits a very low dark current of 10 pA at -30 V with a sharp cutoff at 270 nm. More interestingly, the 90-10% decay time of our device is only around 64 μs, which is much quicker than any other previously reported β-Ga2O3-based photodetectors. Besides, the self-powering, the excellent stability and the good reproducibility of Au/β-Ga2O3 nanowires array film photodetector are helpful to its commercialization and practical applications.

Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1-xN Buffer Layer.

Science.gov (United States)

Lee, Chang-Ju; Won, Chul-Ho; Lee, Jung-Hee; Hahm, Sung-Ho; Park, Hongsik

2017-07-21

The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded Al x Ga -x N buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded Al x Ga 1-x N buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10 - ² A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

Highly sensitive wide bandwidth photodetector based on internal photoemission in CVD grown p-type MoS2/graphene Schottky junction.

Science.gov (United States)

Vabbina, PhaniKiran; Choudhary, Nitin; Chowdhury, Al-Amin; Sinha, Raju; Karabiyik, Mustafa; Das, Santanu; Choi, Wonbong; Pala, Nezih

2015-07-22

Two dimensional (2D) Molybdenum disulfide (MoS2) has evolved as a promising material for next generation optoelectronic devices owing to its unique electrical and optical properties, such as band gap modulation, high optical absorption, and increased luminescence quantum yield. The 2D MoS2 photodetectors reported in the literature have presented low responsivity compared to silicon based photodetectors. In this study, we assembled atomically thin p-type MoS2 with graphene to form a MoS2/graphene Schottky photodetector where photo generated holes travel from graphene to MoS2 over the Schottky barrier under illumination. We found that the p-type MoS2 forms a Schottky junction with graphene with a barrier height of 139 meV, which results in high photocurrent and wide spectral range of detection with wavelength selectivity. The fabricated photodetector showed excellent photosensitivity with a maximum photo responsivity of 1.26 AW(-1) and a noise equivalent power of 7.8 × 10(-12) W/√Hz at 1440 nm.

AlGaN-Based Solar-Blind Schottky Photodetectors Fabricated on AlN/Sapphire Template

International Nuclear Information System (INIS)

Li-Wen, Sang; Zhi-Xin, Qin; Long-Bin, Cen; Bo, Shen; Guo-Yi, Zhang; Shu-Ping, Li; Hang-Yang, Chen; Da-Yi, Liu; Jun-Yong, Kang; Cai-Jing, Cheng; Hong-Yan, Zhao; Zheng-Xiong, Lu; Jia-Xin, Ding; Lan, Zhao; Jun-Jie, Si; Wei-Guo, Sun

2008-01-01

We report AlGaN-based back-illuminated solar-blind Schottky-type ultraviolet photodetectors with the cutoff-wavelength from 280nm to 292nm without bias. The devices show low dark current of 2.1 × 10 −6 A/cm 2 at the reverse bias of 5 V. The specific detectivity D* is estimated to be 3.3 × 10 12 cmHz 1/2 W −1 . To guarantee the performance of the photodetectors, the optimization of AlGaN growth and annealing condition for Schottky contacts were performed. The results show that high-temperature annealing method for Ni/Pt Schottky contacts is effective for the reduction of leakage current

Deep Ultraviolet Copper(I) Thiocyanate (CuSCN) Photodetectors Based on Coplanar Nanogap Electrodes Fabricated via Adhesion Lithography

KAUST Repository

Wyatt-Moon, Gwenhivir

2017-11-28

Adhesion lithography (a-Lith) is a versatile fabrication technique used to produce asymmetric coplanar electrodes separated by a <15 nm nanogap. Here, we use a-Lith to fabricate deep ultraviolet (DUV) photodetectors by combining coplanar asymmetric nanogap electrode architectures (Au/Al) with solution-processable wide-band-gap (3.5–3.9 eV) p-type semiconductor copper(I) thiocyanate (CuSCN). Because of the device’s unique architecture, the detectors exhibit high responsivity (≈79 A W–1) and photosensitivity (≈720) when illuminated with a DUV-range (λpeak = 280 nm) light-emitting diode at 220 μW cm–2. Interestingly, the photosensitivity of the photodetectors remains fairly high (≈7) even at illuminating intensities down to 0.2 μW cm–2. The scalability of the a-Lith process combined with the unique properties of CuSCN paves the way to new forms of inexpensive, yet high-performance, photodetectors that can be manufactured on arbitrary substrate materials including plastic.

Deep Ultraviolet Copper(I) Thiocyanate (CuSCN) Photodetectors Based on Coplanar Nanogap Electrodes Fabricated via Adhesion Lithography

KAUST Repository

Wyatt-Moon, Gwenhivir; Georgiadou, Dimitra G; Semple, James; Anthopoulos, Thomas D.

2017-01-01

Adhesion lithography (a-Lith) is a versatile fabrication technique used to produce asymmetric coplanar electrodes separated by a <15 nm nanogap. Here, we use a-Lith to fabricate deep ultraviolet (DUV) photodetectors by combining coplanar asymmetric nanogap electrode architectures (Au/Al) with solution-processable wide-band-gap (3.5–3.9 eV) p-type semiconductor copper(I) thiocyanate (CuSCN). Because of the device’s unique architecture, the detectors exhibit high responsivity (≈79 A W–1) and photosensitivity (≈720) when illuminated with a DUV-range (λpeak = 280 nm) light-emitting diode at 220 μW cm–2. Interestingly, the photosensitivity of the photodetectors remains fairly high (≈7) even at illuminating intensities down to 0.2 μW cm–2. The scalability of the a-Lith process combined with the unique properties of CuSCN paves the way to new forms of inexpensive, yet high-performance, photodetectors that can be manufactured on arbitrary substrate materials including plastic.

Oxygen vacancy tuned Ohmic-Schottky conversion for enhanced performance in β-Ga{sub 2}O{sub 3} solar-blind ultraviolet photodetectors

Energy Technology Data Exchange (ETDEWEB)

Guo, D. Y.; Wu, Z. P.; An, Y. H.; Guo, X. C.; Chu, X. L.; Sun, C. L.; Tang, W. H., E-mail: whtang@bupt.edu.cn [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Li, L. H. [Physics Department, The State University of New York at Potsdam, Potsdam, New York 13676-2294 (United States); Li, P. G., E-mail: pgli@zstu.edu.cn [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University, Hangzhou, 310018 Zhejiang (China)

2014-07-14

β-Ga{sub 2}O{sub 3} epitaxial thin films were deposited using laser molecular beam epitaxy technique and oxygen atmosphere in situ annealed in order to reduce the oxygen vacancy. Metal/semiconductor/metal structured photodetectors were fabricated using as-grown film and annealed film separately. Au/Ti electrodes were Ohmic contact with the as-grown films and Schottky contact with the annealed films. In compare with the Ohmic-type photodetector, the Schottky-type photodetector takes on lower dark current, higher photoresponse, and shorter switching time, which benefit from Schottky barrier controlling electron transport and the quantity of photogenerated carriers trapped by oxygen vacancy significant decreasing.

Influence of the contact geometry on single-walled carbon nanotube/Si photodetector response

Science.gov (United States)

Scagliotti, Mattia; Salvato, Matteo; De Crescenzi, Maurizio; Boscardin, Maurizio; Castrucci, Paola

2018-03-01

A systematic study of the optical response of photodetectors based on carbon nanotube/Si heterojunctions is performed by measuring the responsivity, the detectivity and the time response of the devices with different contact configurations. The sensors are obtained by dry transferring single-walled carbon nanotube films on the surface of n-doped Si substrate provided with a multifinger contact geometry. The experimental data show a consistent improvement of the photodetector parameters with the increase of the number of fingers without affecting the carbon nanotube film thickness for increase its optical transmittance as in previous experiments. The role of the electrical resistance of the carbon nanotube film is discussed. The obtained results confirm the method and suggest new perspectives in the use of nanostructured materials as part of semiconducting optical devices.

Three-dimensional nano-heterojunction networks: a highly performing structure for fast visible-blind UV photodetectors.

Science.gov (United States)

Nasiri, Noushin; Bo, Renheng; Fu, Lan; Tricoli, Antonio

2017-02-02

Visible-blind ultraviolet photodetectors are a promising emerging technology for the development of wide bandgap optoelectronic devices with greatly reduced power consumption and size requirements. A standing challenge is to improve the slow response time of these nanostructured devices. Here, we present a three-dimensional nanoscale heterojunction architecture for fast-responsive visible-blind UV photodetectors. The device layout consists of p-type NiO clusters densely packed on the surface of an ultraporous network of electron-depleted n-type ZnO nanoparticles. This 3D structure can detect very low UV light densities while operating with a near-zero power consumption of ca. 4 × 10 -11 watts and a low bias of 0.2 mV. Most notably, heterojunction formation decreases the device rise and decay times by 26 and 20 times, respectively. These drastic enhancements in photoresponse dynamics are attributed to the stronger surface band bending and improved electron-hole separation of the nanoscale NiO/ZnO interface. These findings demonstrate a superior structural design and a simple, low-cost CMOS-compatible process for the engineering of high-performance wearable photodetectors.

Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1−xN Buffer Layer

Directory of Open Access Journals (Sweden)

Chang-Ju Lee

2017-07-01

Full Text Available The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded AlxGa−xN buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded AlxGa1−xN buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10−2 A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

Effects of ionizing radiation on cryogenic infrared detectors

Science.gov (United States)

Moseley, S. H.; Silverberg, R. F.; Lakew, B.

1989-01-01

The Diffuse Infrared Background Experiment (DIRBE) is one of three experiments to be carried aboard the Cosmic Background Explorer (COBE) satellite scheduled to be launched by NASA on a Delta rocket in 1989. The DIRBE is a cryogenic absolute photometer operating in a liquid helium dewar at 1.5 K. Photometric stability is a principal requirement for achieving the scientific objectives of this experiment. The Infrared Astronomy Satellite (IRAS), launched in 1983, which used detectors similar to those in DIRBE, revealed substantial changes in detector responsivity following exposure to ionizing radiation encountered on passage through the South Atlantic Anomaly (SAA). Since the COBE will use the same 900 Km sun-synchronous orbit as IRAS, ionizing radiation-induced performance changes in the detectors were a major concern. Here, ionizing radiation tests carried out on all the DIRBE photodetectors are reported. Responsivity changes following exposure to gamma rays, protons, and alpha particle are discussed. The detector performance was monitored following a simulated entire mission life dose. In addition, the response of the detectors to individual particle interactions was measured. The InSb photovoltaic detectors and the Blocked Impurity Band (BIB) detectors revealed no significant change in responsivity following radiation exposure. The Ge:Ga detectors show large effects which were greatly reduced by proper thermal annealing.

Fabrication and characterization of metal–semiconductor–metal ultraviolet photodetector based on rutile TiO{sub 2} nanorod

Energy Technology Data Exchange (ETDEWEB)

Selman, Abbas M., E-mail: alabbasiabbas@yahoo.co.uk [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia); Department of Pharmacology and Toxicology, College of Pharmacy, University of Kufa, Najaf (Iraq); Hassan, Z. [Nano-Optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics, Universiti Sains Malaysia, Penang 11800 (Malaysia)

2016-01-15

The fabrication and characterization of a metal–semiconductor–metal ultraviolet photodetector are studied. The photodetector is based on TiO{sub 2} nanorods (NRs) grown on p-type (1 1 1)-oriented silicon substrate seeded with a TiO{sub 2} layer is synthesized by radio frequency reactive magnetron sputtering. A chemical bath deposition is used to grow TiO{sub 2} NRs on Si substrate. The structural and optical properties of the obtained sample are analyzed by using X-ray diffraction and field emission-scanning electron microscopy. Results show a tetragonal rutile structure of the synthesized TiO{sub 2} NRs. Optical properties are further examined using photoluminescence spectroscopy. A sharp and high-intensity UV peak at 367 nm is observed in comparison with visible defect peaks centered at 432 and 718 nm. Upon exposure to 365 nm light (2.3 mW/cm) at 5 V bias, the device displays 76.06 × 10{sup 2} sensitivity, internal photodetector gain of 77.06, photocurrent of the device is 2.62 × 10{sup −5} A and photoresponse peak of 69.7 mA/W. The response and recovery times are calculated as 18.5 and 19.1 ms upon illumination to a pulse UV light (365 nm, 2.3 mW/cm{sup 2}) at 5 V applied bias. These results demonstrate that the fabricated high-quality photodiode is a promising candidate as a low-cost UV photodetector for commercially-integrated photoelectronic applications.

Broadband Packaging of Photodetectors for 100 Gb/s Ethernet Applications

DEFF Research Database (Denmark)

Jiang, Chenhui; Krozer, Viktor; Bach, Heinz-Gunter

2013-01-01

The packing structure of functional modules is a major limitaion in achieving a desired performance for 100 Gb/s ethernet applications. This paper presents a methodology of developing advanced packaging of photodetectors (PDs) for high-speed data transmission applications by using 3-D electromagn......The packing structure of functional modules is a major limitaion in achieving a desired performance for 100 Gb/s ethernet applications. This paper presents a methodology of developing advanced packaging of photodetectors (PDs) for high-speed data transmission applications by using 3-D...... electromagnetic (EM) simulations. A simplified model of the PD module is first used to analyze and optimize packaging structures and propose an optimal packaging design based on the simplified model. Although a PD module with improved performance proved the success of the optimal packaging design, the simplified...... of limiting the bandwidth of PD modules. After eliminating the mode mismatch effect by improving the chip-conductor-backed coplanar waveguide transition, a final optimal packaging structure is implemented for the PD module with reduced attenuation up to 100 GHz and a broader 3-dB bandwidth of more than 90 GHz...

All-Si photodetector for telecommunication wavelength based on subwavelength grating structure and critical coupling

Directory of Open Access Journals (Sweden)

Alireza Taghizadeh

2017-09-01

Full Text Available We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered subwavelength grating structure topped with a silicide layer of nanometers thickness as an absorbing material. It is shown that a nearly-perfect light absorption is possible for the thin silicide layer by its integration to the grating resonator. The absorption is shown to be maximized when the critical coupling condition is satisfied. Simulations show that the external quantum efficiency of the proposed photodetector with a 2-nm-thick PtSi absorbing layer at the center wavelength of 1550 nm can reach up to ∼60%.

Enhanced Photocurrent in BiFeO3 Materials by Coupling Temperature and Thermo-Phototronic Effects for Self-Powered Ultraviolet Photodetector System.

Science.gov (United States)

Qi, Jia; Ma, Nan; Ma, Xiaochen; Adelung, Rainer; Yang, Ya

2018-04-25

Ferroelectric materials can be utilized for fabricating photodetectors because of the photovoltaic effect. Enhancing the photovoltaic performance of ferroelectric materials is still a challenge. Here, a self-powered ultraviolet (UV) photodetector is designed based on the ferroelectric BiFeO 3 (BFO) material, exhibiting a high current/voltage response to 365 nm light in heating/cooling states. The photovoltaic performance of the BFO-based device can be well modulated by applying different temperature variations, where the output current and voltage can be enhanced by 60 and 75% in heating and cooling states, respectively. The enhancement mechanism of the photocurrent is associated with both temperature effect and thermo-phototronic effect in the photovoltaic process. Moreover, a 4 × 4 matrix photodetector array has been designed for detecting the 365 nm light distribution in the cooling state by utilizing photovoltage signals. This study clarifies the role of the temperature effect and the thermo-phototronic effect in the photovoltaic process of the BFO material and provides a feasible route for pushing forward practical applications of self-powered UV photodetectors.

Split Bull's eye shaped aluminum antenna for plasmon-enhanced nanometer scale germanium photodetector.

Science.gov (United States)

Ren, Fang-Fang; Ang, Kah-Wee; Ye, Jiandong; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

2011-03-09

Bull's eye antennas are capable of efficiently collecting and concentrating optical signals into an ultrasmall area, offering an excellent solution to break the bottleneck between speed and photoresponse in subwavelength photodetectors. Here, we exploit the idea of split bull's eye antenna for a nanometer germanium photodetector operating at a standard communication wavelength of 1310 nm. The nontraditional plasmonic metal aluminum has been implemented in the resonant antenna structure fabricated by standard complementary metal-oxide-semiconductor (CMOS) processing. A significant enhancement in photoresponse could be achieved over the conventional bull's eye scheme due to an increased optical near-field in the active region. Moreover, with this novel antenna design the effective grating area could be significantly reduced without sacrificing device performance. This work paves the way for the future development of low-cost, high-density, and high-speed CMOS-compatible germanium-based optoelectronic devices.

Hybrid III-V/SOI resonant cavity enhanced photodetector

DEFF Research Database (Denmark)

Learkthanakhachon, Supannee; Taghizadeh, Alireza; Park, Gyeong Cheol

2016-01-01

A hybrid III–V/SOI resonant-cavity-enhanced photodetector (RCE-PD) structure comprising a high-contrast grating (HCG) reflector, a hybrid grating (HG) reflector, and an air cavity between them, has been proposed and investigated. In the proposed structure, a light absorbing material is integrated...... as part of the HG reflector, enabling a very compact vertical cavity. Numerical investigations show that a quantum efficiency close to 100 % and a detection linewidth of about 1 nm can be achieved, which are desirable for wavelength division multiplexing applications. Based on these results, a hybrid RCE...

Graphene/h-BN/GaAs sandwich diode as solar cell and photodetector.

Science.gov (United States)

Li, Xiaoqiang; Lin, Shisheng; Lin, Xing; Xu, Zhijuan; Wang, Peng; Zhang, Shengjiao; Zhong, Huikai; Xu, Wenli; Wu, Zhiqian; Fang, Wei

2016-01-11

In graphene/semiconductor heterojunction, the statistic charge transfer between graphene and semiconductor leads to decreased junction barrier height and limits the Fermi level tuning effect in graphene, which greatly affects the final performance of the device. In this work, we have designed a sandwich diode for solar cells and photodetectors through inserting 2D hexagonal boron nitride (h-BN) into graphene/GaAs heterostructure to suppress the static charge transfer. The barrier height of graphene/GaAs heterojunction can be increased from 0.88 eV to 1.02 eV by inserting h-BN. Based on the enhanced Fermi level tuning effect with interface h-BN, through adopting photo-induced doping into the device, power conversion efficiency (PCE) of 10.18% has been achieved for graphene/h-BN/GaAs compared with 8.63% of graphene/GaAs structure. The performance of graphene/h-BN/GaAs based photodetector is also improved with on/off ratio increased by one magnitude compared with graphene/GaAs structure.

Tunable Resonant-Cavity-Enhanced Photodetector with Double High-Index-Contrast Grating Mirrors

DEFF Research Database (Denmark)

Learkthanakhachon, Supannee; Yvind, Kresten; Chung, Il-Sug

2013-01-01

In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists....... Furthermore, the fact that it can be fabricated on a silicon platform offers us a possibility of integration with electronics.......In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists...... of a top InP HCG mirror, a p-i-n photodiode embedding multiple quantum wells, and a Si HCG mirror formed in the Si layer of a silicon-on-insulator wafer. The detection wavelength can be changed by moving the top InP HCG mirror suspended in the air. High reflectivity and small penetration length of HCGs...

Enhanced Graphene Photodetector with Fractal Metasurface

DEFF Research Database (Denmark)

Fang, Jieran; Wang, Di; DeVault, Clayton T

2017-01-01

Graphene has been demonstrated to be a promising photodetection material because of its ultrabroadband optical absorption, compatibility with CMOS technology, and dynamic tunability in optical and electrical properties. However, being a single atomic layer thick, graphene has intrinsically small...... optical absorption, which hinders its incorporation with modern photodetecting systems. In this work, we propose a gold snowflake-like fractal metasurface design to realize broadband and polarization-insensitive plasmonic enhancement in graphene photodetector. We experimentally obtain an enhanced...... photovoltage from the fractal metasurface that is an order of magnitude greater than that generated at a plain gold-graphene edge and such an enhancement in the photovoltage sustains over the entire visible spectrum. We also observed a relatively constant photoresponse with respect to polarization angles...

Monolithic and Flexible ZnS/SnO2 Ultraviolet Photodetectors with Lateral Graphene Electrodes.

Science.gov (United States)

Zhang, Cheng; Xie, Yunchao; Deng, Heng; Tumlin, Travis; Zhang, Chi; Su, Jheng-Wun; Yu, Ping; Lin, Jian

2017-05-01

A continuing trend of miniaturized and flexible electronics/optoelectronic calls for novel device architectures made by compatible fabrication techniques. However, traditional layer-to-layer structures cannot satisfy such a need. Herein, a novel monolithic optoelectronic device fabricated by a mask-free laser direct writing method is demonstrated in which in situ laser induced graphene-like materials are employed as lateral electrodes for flexible ZnS/SnO 2 ultraviolet photodetectors. Specifically, a ZnS/SnO 2 thin film comprised of heterogeneous ZnS/SnO 2 nanoparticles is first coated on polyimide (PI) sheets by a solution process. Then, CO 2 laser irradiation ablates designed areas of the ZnS/SnO 2 thin film and converts the underneath PI into highly conductive graphene as the lateral electrodes for the monolithic photodetectors. This in situ growth method provides good interfaces between the graphene electrodes and the semiconducting ZnS/SnO 2 resulting in high optoelectronic performance. The lateral electrode structure reduces total thickness of the devices, thus minimizing the strain and improving flexibility of the photodetectors. The demonstrated lithography-free monolithic fabrication is a simple and cost-effective method, showing a great potential for developement into roll-to-roll manufacturing of flexible electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultra-wide frequency response measurement of an optical system with a DC photo-detector

KAUST Repository

Kuntz, Katanya B.; Wheatley, Trevor A.; Song, Hongbin; Webb, James G.; Mabrok, Mohamed; Huntington, Elanor H.; Yonezawa, Hidehiro

2017-01-01

Precise knowledge of an optical device's frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of these devices continue to increase, there is a growing need for a characterization method that does not have bandwidth limitations, or require a previously calibrated device. We demonstrate a new calibration technique on an optical system (consisting of an optical cavity and a high-speed waveguide modulator) that is free from limitations imposed by detector bandwidth, and does not require a calibrated photo-detector or modulator. We use a low-frequency (DC) photo-detector to monitor the cavity's optical response as a function of modulation frequency, which is also used to determine the modulator's frequency response. Knowledge of the frequency-dependent modulation depth allows us to more precisely determine the cavity's characteristics (free spectral range and linewidth). The precision and repeatability of our technique is demonstrated by measuring the different resonant frequencies of orthogonal polarization cavity modes caused by the presence of a non-linear crystal. Once the modulator has been characterized using this simple method, the frequency response of any passive optical element can be determined to a fine resolution (e.g. kilohertz) over several gigahertz.

Enhanced Electron Photoemission by Collective Lattice Resonances in Plasmonic Nanoparticle-Array Photodetectors and Solar Cells

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Babicheva, Viktoriia; Uskov, Alexander

2014-01-01

We propose to use collective lattice resonances in plasmonic nanoparticle arrays to enhance and tailor photoelectron emission in Schottky barrier photodetectors and solar cells. We show that the interaction between narrow-band lattice resonances (the Rayleigh anomaly) and broader-band individual-particle...... excitations (localized surface plasmon resonances) leads to stronger local field enhancement. In turn, this causes a significant increase of the photocurrent compared to the case when only individual-particle excitations are present. The results can be used to design new photodetectors with highly selective......, tunable spectral response, which are able to detect photons with the energy below the semiconductor bandgap. The findings can also be used to develop solar cells with increased efficiency....

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity

KAUST Repository

Leung, Siu; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K. S.; Alshareef, Husam N.; Wang, Zhong Lin; He, Jr-Hau

2018-01-01

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3 NH3 PBI3

Local irradiation effects of one-dimensional ZnO based self-powered asymmetric Schottky barrier UV photodetector

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yaxue [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Qi, Junjie, E-mail: junjieqi@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Biswas, Chandan [Department of Electrical Engineering, University of California Los Angeles, California 90095 (United States); Li, Feng; Zhang, Kui; Li, Xin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Yue, E-mail: yuezhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083 (China)

2015-09-15

A self-powered metal-semiconductor-metal (MSM) UV photodetector was successfully fabricated based on Ag/ZnO/Au structure with asymmetric Schottky barriers. This exhibits excellent performance compared to many previous studies. Very high photo-to-dark current ratio (approximately 10{sup 5}–10{sup 6}) was demonstrated without applying any external bias, and very fast switching time of less than 30 ms was observed during the investigation. Opposite photocurrent direction was generated by irradiating different Schottky diodes in the fabricated photodetector. Furthermore, the device performance was optimized by largely irradiating both the ZnO microwire (MW) junctions. Schottky barrier effect theory and O{sub 2} adsorption–desorption theories were used to investigate the phenomenon. The device has potential applications in self-powered UV detection field and can be used as electrical power source for electronic, optoelectronic and mechanical devices. - Highlights: • A self-powered Schottky barrier UV photodetector based on 1-D ZnO is fabricated. • For the first time we investigate the local irradiation effects of UV detector. • Irradiating both the junctions and ZnO can optimize the performance of the device.

Donor and Acceptor Polymers for Bulk Hetero Junction Solar Cell and Photodetector Applications

KAUST Repository

Cruciani, Federico

2018-01-01

-13% and being a step closer to practical applications. Among the photodetectors (PD), low band gap polymer blended with PCBM decked out the attention, given their extraordinary range of detection from UV to IR and high detectivity values reached so far, compared

Infrared detection and photon energy up-conversion in graphene layer infrared photodetectors integrated with LEDs based on van der Waals heterostructures: Concept, device model, and characteristics

Science.gov (United States)

Ryzhii, V.; Otsuji, T.; Ryzhii, M.; Karasik, V. E.; Shur, M. S.

2017-09-01

We propose the concept of the infrared detection and photon energy up-conversion in the devices using the integration of the graphene layer infrared detectors (GLIPs) and the light emitting diodes (LEDs) based on van der Waals (vdW) heterostructures. Using the developed device model of the GLIP-LEDs, we calculate their characteristics. The GLIP-LED devices can operate as the detectors of far- and mid infrared radiation (FIR and MIR) with an electrical output or with near-infrared radiation (NIR) or visible radiation (VIR) output. In the latter case, GLIP-LED devices function as the photon energy up-converters of FIR and MIR to NIR or VIR. The operation of GLIP-LED devices is associated with the injection of the electron photocurrent produced due to the interband absorption of the FIR/MIR photons in the GLIP part into the LED emitting NIR/VIR photons. We calculate the GLIP-LED responsivity and up-conversion efficiency as functions the structure parameters and the energies of the incident FIR/MIR photons and the output NIR/VIR photons. The advantages of the GLs in the vdW heterostructures (relatively high photoexcitation rate from and low capture efficiency into GLs) combined with the reabsorption of a fraction of the NIR/FIR photon flux in the GLIP (which can enable an effective photonic feedback) result in the elevated GLIP-LED device responsivity and up-conversion efficiency. The positive optical feedback from the LED section of the device lead to increasing current injection enabling the appearance of the S-type current-voltage characteristic with a greatly enhanced responsivity near the switching point and current filamentation.

Robust and Air-Stable Sandwiched Organo-Lead Halide Perovskites for Photodetector Applications

KAUST Repository

Mohammed, Omar F.

2016-02-25

We report the simplest possible method to date for fabricating robust, air-stable, sandwiched perovskite photodetectors. Our proposed sandwiched structure is devoid of electron or hole transporting layers and also the expensive electrodes. These simpler architectures may have application in the perovskite-only class of solar cells scaling up towards commercialization.

An ultraviolet photodetector fabricated from WO3 nanodiscs/reduced graphene oxide composite material

International Nuclear Information System (INIS)

Shao Dali; Sawyer, Shayla; Yu Mingpeng; Lian Jie

2013-01-01

A high sensitivity, fast ultraviolet (UV) photodetector was fabricated from WO 3 nanodiscs (NDs)/reduced graphene oxide (RGO) composite material. The WO 3 NDs/reduced GO composite material was synthesized using a facile three-step synthesis procedure. First, the Na 2 WO 4 /GO precursor was synthesized by homogeneous precipitation. Second, the Na 2 WO 4 /GO precursor was transformed into H 2 WO 4 /GO composites by acidification. Finally, the H 2 WO 4 /GO composites were reduced to WO 3 NDs/RGO via a hydrothermal reduction process. The UV photodetector showed a fast transient response and high responsivity, which are attributed to the improved carrier transport and collection efficiency through graphene. The excellent material properties of the WO 3 NDs/RGO composite demonstrated in this work may open up new possibilities for using WO 3 NDs/RGO for future optoelectronic applications. (paper)

Zero-biased solar-blind photodetector based on ZnBeMgO/Si heterojunction

International Nuclear Information System (INIS)

Yang, C; Li, X M; Yu, W D; Gao, X D; Cao, X; Li, Y Z

2009-01-01

An n-type Zn 1-x-y Be x Mg y O thin film was deposited on a p-type Si substrate by pulsed laser deposition to obtain a solar-blind photodetector. The spectral response characteristic with a cutoff wavelength of 280 nm was demonstrated to realize the photodetection of the solar-blind wave zone. The responsivity of the device was improved by inserting an Al-doped ZnO (AZO) contact layer, which was expected to enhance the carrier collection efficiency significantly. Correspondingly, the peak responsivity was improved from 0.003 to 0.11 A W -1 at zero bias, and a high external quantum efficiency of 53% at 270 nm was achieved. The fast rise time reached 20 ns. This work demonstrated the possibility of a wurtzite ZnO based oxide system to realize high performance zero-biased solar-blind photodetectors. (fast track communication)

Inkjet-printed transparent nanowire thin film features for UV photodetectors

KAUST Repository

Chen, Shih Pin

2015-01-01

In this study, a simple and effective direct printing method was developed to print patterned nanowire thin films for UV detection. Inks containing silver or titanium dioxide (TiO2) nanowires were first formulated adequately to form stable suspension for inkjet printing applications. Sedimentation tests were also carried out to characterize the terminal velocity and dispersion stability of nanowires to avoid potential nozzle clogging problems. The well-dispersed silver nanowire ink was then inkjet printed on PET films to form patterned electrodes. Above the electrodes, another layer of TiO2 nanowires was also printed to create a highly transparent photodetector with >80% visible transmittance. The printed photodetector showed a fairly low dark current of 10-12-10-14 A with a high on/off ratio of 2000 to UV radiation. Under a bias voltage of 2 V, the detector showed fast responses to UV illumination with a rise time of 0.4 s and a recovery time of 0.1 s. More photo currents can also be collected with a larger printed electrode area. In summary, this study shows the feasibility of applying inkjet printing technology to create nanowire thin films with specific patterns, and can be further employed for photoelectric applications. © The Royal Society of Chemistry 2015.

Largely Improved Near-Infrared Silicon-Photosensing by the Piezo-Phototronic Effect.

Science.gov (United States)

Dai, Yejing; Wang, Xingfu; Peng, Wenbo; Zou, Haiyang; Yu, Ruomeng; Ding, Yong; Wu, Changsheng; Wang, Zhong Lin

2017-07-25

Although silicon (Si) devices are the backbone of modern (opto-)electronics, infrared Si-photosensing suffers from low-efficiency due to its limitation in light-absorption. Here, we demonstrate a large improvement in the performance, equivalent to a 366-fold enhancement in photoresponsivity, of a Si-based near-infrared (NIR) photodetector (PD) by introducing the piezo-phototronic effect via a deposited CdS layer. By externally applying a -0.15‰ compressive strain to the heterojunction, carrier-dynamics modulation at the local junction can be induced by the piezoelectric polarization, and the photoresponsivity and detectivity of the PD exhibit an enhancement of two orders of magnitude, with the peak values up to 19.4 A/W and 1.8 × 10 12 cm Hz 1/2 /W, respectively. The obtained maximum responsivity is considerably larger than those of commercial Si and InGaAs PDs in the NIR waveband. Meanwhile, the rise time and fall time are reduced by 84.6% and 76.1% under the external compressive strain. This work provides a cost-effective approach to achieve high-performance NIR photosensing by the piezo-phototronic effect for high-integration Si-based optoelectronic systems.

Electrical circuit model of ITO/AZO/Ge photodetector.

Science.gov (United States)

Patel, Malkeshkumar; Kim, Joondong

2017-10-01

In this data article, ITO/AZO/Ge photodetector was investigated for electrical circuit model. Due to the double (ITO and AZO) transparent metal-oxide films (DOI:10.1016/j.mssp.2016.03.007) (Yun et al., 2016) [1], the Ge heterojunction device has a better interface quality due to the AZO layer with a low electrical resistance due to the ITO layer (Yun et al., 2015) [2]. The electrical and interfacial benefitted ITO/AZO/Ge heterojunction shows the quality Schottky junction. In order to investigate the device, the ITO/AZO/Ge heterojunction was analyzed by R-C circuit model using the impedance spectroscopy.

Ultra-wide frequency response measurement of an optical system with a DC photo-detector

KAUST Repository

Kuntz, Katanya B.

2017-01-09

Precise knowledge of an optical device\\'s frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of these devices continue to increase, there is a growing need for a characterization method that does not have bandwidth limitations, or require a previously calibrated device. We demonstrate a new calibration technique on an optical system (consisting of an optical cavity and a high-speed waveguide modulator) that is free from limitations imposed by detector bandwidth, and does not require a calibrated photo-detector or modulator. We use a low-frequency (DC) photo-detector to monitor the cavity\\'s optical response as a function of modulation frequency, which is also used to determine the modulator\\'s frequency response. Knowledge of the frequency-dependent modulation depth allows us to more precisely determine the cavity\\'s characteristics (free spectral range and linewidth). The precision and repeatability of our technique is demonstrated by measuring the different resonant frequencies of orthogonal polarization cavity modes caused by the presence of a non-linear crystal. Once the modulator has been characterized using this simple method, the frequency response of any passive optical element can be determined to a fine resolution (e.g. kilohertz) over several gigahertz.

Graphene/black phosphorus heterostructured photodetector

Science.gov (United States)

Xu, Jiao; Song, Young Jae; Park, Jin-Hong; Lee, Sungjoo

2018-06-01

Graphene photodetectors exhibit a low photoresponsivity due to their weak light absorbance. In this study, we fabricated a graphene/black phosphorus (BP) heterostructure, in which the multilayer BP flake with a ∼0.3 eV direct band gap functions as an enhanced light-absorption material. Further, the photoexcited electrons are trapped in the trap states of the BP, which creates a photogating effect and causes holes to flow into the graphene layer driven by the built-in potential between BP and graphene. The photocarrier lifetime is therefore prolonged by trapping, and as a result of the high carrier mobility of graphene, the holes that transfer into the graphene channel can travel through the circuit before they recombine with trapped electrons. These combined effects result in a high photoresponsivity: 55.75 A/W at λ = 655 nm, 1.82 A/W at λ = 785 nm, and 0.66 A/W at λ = 980 nm.

Solvent-induced crystallization for hybrid perovskite thin-film photodetector with high-performance and low working voltage

International Nuclear Information System (INIS)

Hu, Wei; Yang, Shuzhen; Fan, Peng; Pan, Anlian; Wu, Runsheng; Yang, Junliang

2017-01-01

Organometal trihalide perovskites have emerged as a class of solution-processed semiconductors exhibiting remarkable optoelectronic properties. Using a high-quality perovskite thin film prepared by solvent-induced crystallization method and adopting a novel device configuration based on photon recycling effect, a perovskite thin-film photodetector has been constructed with the highest external quantum efficiency of 4.1  ×  10 4 % and responsivity of 219 A W −1 at a low bias of 1 V so far. The device working mechanism was further disclosed based on energy band bending model. The high-performance and low working-voltage perovskite thin-film photodetector will find potential applications in photodetection and optoelectronic integrated circuits. (paper)

Enhanced Response Speed of ZnO Nanowire Photodetector by Coating with Photoresist

Directory of Open Access Journals (Sweden)

Xing Yang

2016-01-01

Full Text Available Spin-coating photoresist film on ZnO nanowire (NW was introduced into the fabrication procedure to improve photoresponse and recovery speed of a ZnO NW ultraviolet photoelectric detector. A ZnO NW was first assembled on prefabricated electrodes by dielectrophoresis. Then, photoresist was spin-coated on the nanowire. Finally, a metal layer was electrodeposited on the nanowire-electrode contacts. The response properties and I-V characteristics of ZnO NW photodetector were investigated by measuring the electrical current under different conditions. Measurement results demonstrated that the detector has an enhanced photoresponse and recovery speed after coating the nanowire with photoresist. The photoresponse and recovery characteristics of detectors with and without spin-coating were compared to demonstrate the effects of photoresist and the enhancement of response and recovery speed of the photodetector is ascribed to the reduced surface absorbed oxygen molecules and binding effect on the residual oxygen molecules after photoresist spin-coating. The results demonstrated that surface coating may be an effective and simple way to improve the response speed of the photoelectric device.

FABRICATION, MORPHOLOGICAL AND OPTOELECTRONIC PROPERTIES OF ANTIMONY ON POROUS SILICON AS MSM PHOTODETECTOR

Directory of Open Access Journals (Sweden)

H. A. Hadi

2015-07-01

Full Text Available We report on the fabrication and characterization of MSM photodetector. We investigated the surface morphological and the structural properties of the porous silicon by optical microscopy, atomic force microscope (AFM and X-ray diffraction. The metal–semiconductor–metal photodetector were fabricated by using Sb as Schottky contact metal.The junction exhibits good rectification ratio of 105 at bias of 2V. A large photocurrent to dark-current contrast ratio higher than 55 orders of magnitude and low dark currents below 0.89 nA .High   responsivity of 0.225A/W at 400 nm and 0.15 A/W at 400 and 700nm were observed at an operating bias of less than -2 V, corresponding quantum efficiency of 70% and 26% respectively. The lifetimes are evaluated using OCVD method and the carrier life time is 100 μs. The results show that Sb on porous silicon (PS structures will act as good candidates for making highly efficient photodiodes.

FABRICATION, MORPHOLOGICAL AND OPTOELECTRONIC PROPERTIES OF ANTIMONY ON POROUS SILICON AS MSM PHOTODETECTOR

Directory of Open Access Journals (Sweden)

H. A. Hadi

2014-12-01

Full Text Available We report on the fabrication and characterization of MSM photodetector. We investigated the surface morphological and the structural properties of the porous silicon by optical microscopy, atomic force microscope (AFM and X-ray diffraction. The metal–semiconductor–metal photodetector were fabricated by using Sb as Schottky contact metal.The junction exhibits good rectification ratio of 105 at bias of 2V. A large photocurrent to dark-current contrast ratio higher than 55 orders of magnitude and low dark currents below 0.89 nA .High responsivity of 0.225A/W at 400 nm and 0.15 A/W at 400 and 700nm were observed at an operating bias of less than -2 V, corresponding quantum efficiency of 70% and 26% respectively. The lifetimes are evaluated using OCVD method and the carrier life time is 100 μs. The results show that Sb on porous silicon (PS structures will act as good candidates for making highly efficient photodiodes.

Design and fabrication of prototype 6×6 cm2 microchannel plate photodetector with bialkali photocathode for fast timing applications

International Nuclear Information System (INIS)

Xie, Junqi; Byrum, Karen; Demarteau, Marcel; Gregar, Joseph; May, Edward; Virgo, Mathew; Wagner, Robert; Walters, Dean; Wang, Jingbo; Xia, Lei; Zhao, Huyue

2015-01-01

Planar microchannel plate-based photodetectors with a bialkali photocathode are able to achieve photon detection with very good time and position resolution. A 6×6 cm 2 photodetector production facility was designed and built at Argonne National Laboratory. Small form-factor MCP-based photodetectors completely constructed out of glass were designed and prototypes were successfully fabricated. Knudsen effusion cells were incorporated in the photocathode growth chamber to achieve uniform and high quantum efficiency photocathodes. The thin film uniformity was simulated and measured for an antimony film deposition, showing uniformity of better than 10%. Several prototype devices with bialkali photocathodes have been fabricated with the described system and their characteristics were evaluated in the large signal (multi-PE) limit. A typical prototype device exhibits time-of-flight resolution of ~27 psec and differential time resolution of ~9 psec, corresponding to spatial resolution of ~0.65 mm

Visible-blind ultraviolet photodetector based on double heterojunction of n-ZnO/insulator-MgO/p-Si

International Nuclear Information System (INIS)

Zhang, T. C.; Guo, Y.; Mei, Z. X.; Gu, C. Z.; Du, X. L.

2009-01-01

Exploiting a double heterojunction of n-ZnO/insulator-MgO/p-Si grown by molecular beam epitaxy, a visible-blind ultraviolet (UV) photodetector has been fabricated. The photodetector shows a rectification ratio of ∼10 4 at ±2 V and a dark current of 0.5 nA at a reverse bias of -2 V.The photoresponse spectrum indicates a visible-blind UV detectivity of our devices with a sharp cut off at the wavelength of 378 nm and a high UV/visible rejection ratio. The key role of the middle insulating MgO layer, as a barrier layer for minority carrier transport, has been demonstrated

Efficient Sub-Bandgap Light Absorption and Signal Amplification in Silicon Photodetectors

Science.gov (United States)

Liu, Yu-Hsin

This thesis focuses on two areas in silicon photodetectors, the first being enhancing the sub-bandgap light absorption of IR wavelenghts in silicon, and the second being intrinsic signal amplification in silicon photodetectors. Both of these are achieved using heavily doped p-n junction devices which create localized states that relax the k-selection rule of indirect bandgap material. The probability of transitions between impurity band and the conduction/valence band would be much more efficient than the one between band-to-band transition. The waveguide-coupled epitaxial p-n photodetector was demonstrated for 1310 nm wavelength detection. Incorporated with the Franz-Keldysh effect and the quasi-confined epitaxial layer design, an absorption coefficient around 10 cm-1 has been measured and internal quantum efficiency nearly 100% at -2.5V. The absorption coefficient is calculated from the wave function of the electron and hole in p-n diode. The heavily doped impurity wave function can be formulated as a delta function, and the quasi-confined conduction band energy states, and the wave function on each level can be obtained from the Silvaco software. The calculated theoretical absorption coefficient increases with the increasing applied bias and the doping concentration, which matches the experimental results. To solve the issues of large excess noise and high operation bias for avalanche photodiodes based on impact ionization, I presented a detector using the Cycling Excitation Process (CEP) for signal amplification. This can be realized in a heavily doped and highly compensated Si p-n junction, showing ultra high gain about 3000 at very low bias (<4 V), and possessing an intrinsic, phonon-mediated regulation process to keep the device stable without any quenching device required in today's Geiger-mode avalanche detectors. The CEP can be formulated with the rate equations in conduction bands and impurity states. The gain expression, which is a function of the

Fast and Sensitive Solution-Processed Visible-Blind Perovskite UV Photodetectors.

Science.gov (United States)

Adinolfi, Valerio; Ouellette, Olivier; Saidaminov, Makhsud I; Walters, Grant; Abdelhady, Ahmed L; Bakr, Osman M; Sargent, Edward H

2016-09-01

The first visible-blind UV photodetector based on MAPbCl3 integrated on a substrate exhibits excellent performance, with responsivities reaching 18 A W(-1) below 400 nm and imaging-compatible response times of 1 ms. This is achieved by using substrate-integrated single crystals, thus overcoming the severe limitations affecting thin films and offering a new application of efficient, solution-processed, visible-transparent perovskite optoelectronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of InGaAs short wave infrared avalanche photodetector for low flux imaging

Science.gov (United States)

Singh, Anand; Pal, Ravinder

2017-11-01

Opto-electronic performance of the InGaAs/i-InGaAs/InP short wavelength infrared focal plane array suitable for high resolution imaging under low flux conditions and ranging is presented. More than 85% quantum efficiency is achieved in the optimized detector structure. Isotropic nature of the wet etching process poses a challenge in maintaining the required control in the small pitch high density detector array. Etching process is developed to achieve low dark current density of 1 nA/cm2 in the detector array with 25 µm pitch at 298 K. Noise equivalent photon performance less than one is achievable showing single photon detection capability. The reported photodiode with low photon flux is suitable for active cum passive imaging, optical information processing and quantum computing applications.

Electrical circuit model of ITO/AZO/Ge photodetector

Directory of Open Access Journals (Sweden)

Malkeshkumar Patel

2017-10-01

Full Text Available In this data article, ITO/AZO/Ge photodetector was investigated for electrical circuit model. Due to the double (ITO and AZO transparent metal-oxide films (DOI:10.1016/j.mssp.2016.03.007 (Yun et al., 2016 [1], the Ge heterojunction device has a better interface quality due to the AZO layer with a low electrical resistance due to the ITO layer (Yun et al., 2015 [2]. The electrical and interfacial benefitted ITO/AZO/Ge heterojunction shows the quality Schottky junction. In order to investigate the device, the ITO/AZO/Ge heterojunction was analyzed by R–C circuit model using the impedance spectroscopy.

Factors affecting the stability and performance of ionic liquid-based planar transient photodetectors.

Science.gov (United States)

Dalgleish, Simon; Reissig, Louisa; Hu, Laigui; Matsushita, Michio M; Sudo, Yuki; Awaga, Kunio

2015-05-12

A novel planar architecture has been developed for the study of photodetectors utilizing the transient photocurrent response induced by a metal/insulator/semiconductor/metal (MISM) structured device, where the insulator is an ionic liquid (IL-MISM). Using vanadyl 2,3-naphthalocyanine, which absorbs in the communications-relevant near-infrared wavelength region (λ(max,film) ≈ 850 nm), in conjunction with C60 as a bulk heterojunction, the high capacitance of the formed electric double layers at the ionic liquid interfaces yields high charge separation efficiency within the semiconductor layer, and the minimal potential drop in the bulk ionic liquid allows the electrodes to be offset by distances of over 7 mm. Furthermore, the decrease in operational speed with increased electrode separation is beneficial for a clear modeling of the waveform of the photocurrent signal, free from the influence of measurement circuitry. Despite the use of a molecular semiconductor as the active layer in conjunction with a liquid insulating layer, devices with a stability of several days could be achieved, and the operational stability of such devices was shown to be dependent solely on the solubility of the active layer in the ionic liquid, even under atmospheric conditions. Furthermore, the greatly simplified device construction process, which does not rely on transparent electrode materials or direct electrode deposition, provides a highly reproducible platform for the study of the electronic processes within IL-MISM detectors that is largely free from architectural constraints.

Theoretical Analysis of Interferometer Wave Front Tilt and Fringe Radiant Flux on a Rectangular Photodetector

Directory of Open Access Journals (Sweden)

Franz Konstantin Fuss

2013-09-01

Full Text Available This paper is a theoretical analysis of mirror tilt in a Michelson interferometer and its effect on the radiant flux over the active area of a rectangular photodetector or image sensor pixel. It is relevant to sensor applications using homodyne interferometry where these opto-electronic devices are employed for partial fringe counting. Formulas are derived for radiant flux across the detector for variable location within the fringe pattern and with varying wave front angle. The results indicate that the flux is a damped sine function of the wave front angle, with a decay constant of the ratio of wavelength to detector width. The modulation amplitude of the dynamic fringe pattern reduces to zero at wave front angles that are an integer multiple of this ratio and the results show that the polarity of the radiant flux changes exclusively at these multiples. Varying tilt angle causes radiant flux oscillations under an envelope curve, the frequency of which is dependent on the location of the detector with the fringe pattern. It is also shown that a fringe count of zero can be obtained for specific photodetector locations and wave front angles where the combined effect of fringe contraction and fringe tilt can have equal and opposite effects. Fringe tilt as a result of a wave front angle of 0.05° can introduce a phase measurement difference of 16° between a photodetector/pixel located 20 mm and one located 100 mm from the optical origin.

Exploration of the Infrared Sensitivity for a ZnSe Electrode of an IR Image Converter

Science.gov (United States)

Kurt, H. Hilal

2018-05-01

Significant improvement has been carried out in the field of the II-VI group semiconductor device technology. Semiconductors based on the II-VI group are attractive due to their alternative uses for thermal imaging systems and photonic applications. This study focuses on experimental work on the optical, electrical and structural characterization of an infrared (IR) photodetector zinc selenide (ZnSe). In addition, the IR sensitivity of the ZnSe has primarily been investigated by exploiting the IR responses of the material for various gas pressures, p, and interelectrode distances, d, in the IR converter. The experimental findings include the results of plasma current and plasma discharge emission under various illumination conditions in the IR region. The electron density distributions inside the gas discharge gap have also been simulated in two-dimensional media. Experimentally, the current-voltage, current-time, and discharge light emission plots are produced for a wide experimental parameter range. Consequently, the structural and optical properties have been studied through atomic force microscopy and Fourier-transform infrared spectroscopy techniques to obtain a comprehensive knowledge of the material.

Effects of radiation and temperature on gallium nitride (GaN) metal-semiconductor-metal ultraviolet photodetectors

Science.gov (United States)

Chiamori, Heather C.; Angadi, Chetan; Suria, Ateeq; Shankar, Ashwin; Hou, Minmin; Bhattacharya, Sharmila; Senesky, Debbie G.

2014-06-01

The development of radiation-hardened, temperature-tolerant materials, sensors and electronics will enable lightweight space sub-systems (reduced packaging requirements) with increased operation lifetimes in extreme harsh environments such as those encountered during space exploration. Gallium nitride (GaN) is a ceramic, semiconductor material stable within high-radiation, high-temperature and chemically corrosive environments due to its wide bandgap (3.4 eV). These material properties can be leveraged for ultraviolet (UV) wavelength photodetection. In this paper, current results of GaN metal-semiconductor-metal (MSM) UV photodetectors behavior after irradiation up to 50 krad and temperatures of 15°C to 150°C is presented. These initial results indicate that GaN-based sensors can provide robust operation within extreme harsh environments. Future directions for GaN-based photodetector technology for down-hole, automotive and space exploration applications are also discussed.

Simulation based comparative analysis of photoresponse in front- and back-illuminated GaN P-I-N ultraviolet photodetectors

Science.gov (United States)

Wang, Jun; Guo, Jin; Xie, Feng; Wang, Guosheng; Wu, Haoran; Song, Man; Yi, Yuanyuan

2016-10-01

This paper presents the comparative analysis of influence of doping level and doping profile of the active region on zero bias photoresponse characteristics of GaN-based p-i-n ultraviolet (UV) photodetectors operating at front- and back-illuminated. A two dimensional physically-based computer simulation of GaN-based p-i-n UV photodetectors is presented. We implemented GaN material properties and physical models taken from the literature. It is shown that absorption layer doping profile has notable impacts on the photoresponse of the device. Especially, the effect of doping concentration and distribution of the absorption layer on photoresponse is discussed in detail. In the case of front illumination, comparative to uniform n-type doping, the device with n-type Gaussian doping profiles at absorption layer has higher responsivity. Comparative to front illumination, back illuminated detector with p-type doping profiles at absorption layer has higher maximum photoresponse, while the Gaussian doping profiles have a weaker ability to enhance the device responsivity. It is demonstrated that electric field distribution, mobility degradation, and recombinations are jointly responsible for the variance of photoresponse. Our work enriches the understanding and utilization of GaN based p-i-n UV photodetectors.

Love Wave Ultraviolet Photodetector Fabricated on a TiO2/ST-Cut Quartz Structure

Directory of Open Access Journals (Sweden)

Walter Water

2014-01-01

Full Text Available A TiO2 thin film deposited on a 90° rotated 42°45′ ST-cut quartz substrate was applied to fabricate a Love wave ultraviolet photodetector. TiO2 thin films were grown by radio frequency magnetron sputtering. The crystalline structure and surface morphology of TiO2 thin films were examined using X-ray diffraction, scanning electron microscope, and atomic force microscope. The effect of TiO2 thin film thickness on the phase velocity, electromechanical coupling coefficient, temperature coefficient of frequency, and sensitivity of ultraviolet of devices was investigated. TiO2 thin film increases the electromechanical coupling coefficient but decreases the temperature coefficient of frequency for Love wave propagation on the 90° rotated 42°45′ ST-cut quartz. For Love wave ultraviolet photodetector application, the maximum insertion loss shift and phase shift are 2.81 dB and 3.55 degree at the 1.35-μm-thick TiO2 film.

Broad spectral response photodetector based on individual tin-doped CdS nanowire

Directory of Open Access Journals (Sweden)

Weichang Zhou

2014-12-01

Full Text Available High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

A Brief Technical History of the Large-Area Picosecond Photodetector (LAPPD) Collaboration

Energy Technology Data Exchange (ETDEWEB)

Adams, B.W.; et al.

2016-03-06

The Large Area Picosecond PhotoDetector (LAPPD) Collaboration was formed in 2009 to develop large-area photodetectors capable of time resolutions measured in pico-seconds, with accompanying sub-millimeter spatial resolution. During the next three and one-half years the Collaboration developed the LAPPD design of 20 x 20 cm modules with gains greater than $10^7$ and non-uniformity less than $15\\%$, time resolution less than 50 psec for single photons and spatial resolution of 700~microns in both lateral dimensions. We describe the R\\&D performed to develop large-area micro-channel plate glass substrates, resistive and secondary-emitting coatings, large-area bialkali photocathodes, and RF-capable hermetic packaging. In addition, the Collaboration developed the necessary electronics for large systems capable of precise timing, built up from a custom low-power 15-GigaSample/sec waveform sampling 6-channel integrated circuit and supported by a two-level modular data acquisition system based on Field-Programmable Gate Arrays for local control, data-sparcification, and triggering. We discuss the formation, organization, and technical successes and short-comings of the Collaboration. The Collaboration ended in December 2012 with a transition from R\\&D to commercialization.

Piezo-Phototronic Enhanced UV Sensing Based on a Nanowire Photodetector Array.

Science.gov (United States)

Han, Xun; Du, Weiming; Yu, Ruomeng; Pan, Caofeng; Wang, Zhong Lin

2015-12-22

A large array of Schottky UV photodetectors (PDs) based on vertical aligned ZnO nanowires is achieved. By introducing the piezo-phototronic effect, the performance of the PD array is enhanced up to seven times in photoreponsivity, six times in sensitivity, and 2.8 times in detection limit. The UV PD array may have applications in optoelectronic systems, adaptive optical computing, and communication. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-powered and broadband photodetectors based on graphene/ZnO/silicon triple junctions

Energy Technology Data Exchange (ETDEWEB)

Cheng, Ching-Cheng; Liao, Yu-Ming; Chen, Yang-Fang, E-mail: yfchen@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Zhan, Jun-Yu; Lin, Tai-Yuan [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China); Hsieh, Ya-Ping [Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

2016-08-01

A self-powered photodetector with ultrahigh sensitivity, fast photoresponse, and wide spectral detectivity covering from 1000 nm to 400 nm based on graphene/ZnO/Si triple junctions has been designed, fabricated, and demonstrated. In this device, graphene serves as a transparent electrode as well as an efficient collection layer for photogenerated carriers due to its excellent tunability of Fermi energy. The ZnO layer acts as an antireflection layer to trap the incident light and enhance the light absorption. Furthermore, the insertion of the ZnO layer in between graphene and Si layers can create build-in electric field at both graphene/ZnO and ZnO/Si interfaces, which can greatly enhance the charge separation of photogenerated electron and hole pairs. As a result, the sensitivity and response time can be significantly improved. It is believed that our methodology for achieving a high-performance self-powered photodetector based on an appropriate design of band alignment and optical parameters can be implemented to many other material systems, which can be used to generate unique optoelectronic devices for practical applications.

High-Performance Red-Light Photodetector Based on Lead-Free Bismuth Halide Perovskite Film.

Science.gov (United States)

Tong, Xiao-Wei; Kong, Wei-Yu; Wang, You-Yi; Zhu, Jin-Miao; Luo, Lin-Bao; Wang, Zheng-Hua

2017-06-07

In this study, we developed a sensitive red-light photodetector (RLPD) based on CsBi 3 I 10 perovskite thin film. This inorganic, lead-free perovskite was fabricated by a simple spin-coating method. Device analysis reveals that the as-assembled RLPD was very sensitive to 650 nm light, with an on/off ratio as high as 10 5 . The responsivity and specific detectivity of the device were estimated to be 21.8 A/W and 1.93 × 10 13 Jones, respectively, which are much better than those of other lead halide perovskite devices. In addition, the device shows a fast response (rise time: 0.33 ms; fall time: 0.38 ms) and a high external quantum efficiency (4.13 × 10 3 %). It is also revealed that the RLPD has a very good device stability even after storage for 3 months under ambient conditions. In summary, we suggest that the CsBi 3 I 10 perovskite photodetector developed in this study may have potential applications in future optoelectronic systems.

Development of a 144-channel Hybrid Avalanche Photo-Detector for Belle II ring-imaging Cherenkov counter with an aerogel radiator

Energy Technology Data Exchange (ETDEWEB)

Nishida, S., E-mail: shohei.nishida@kek.jp [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Adachi, I. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Hamada, N. [Toho University, Funabashi (Japan); Hara, K. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Iijima, T. [Nagoya University, Nagoya (Japan); Iwata, S.; Kakuno, H. [Tokyo Metropolitan University, Hachioji (Japan); Kawai, H. [Chiba University, Chiba (Japan); Korpar, S.; Krizan, P. [Jozef Stefan Institute, Ljubljana (Slovenia); Ogawa, S. [Toho University, Funabashi (Japan); Pestotnik, R.; Ŝantelj, L.; Seljak, A. [Jozef Stefan Institute, Ljubljana (Slovenia); Sumiyoshi, T. [Tokyo Metropolitan University, Hachioji (Japan); Tabata, M. [Chiba University, Chiba (Japan); Tahirovic, E. [Jozef Stefan Institute, Ljubljana (Slovenia); Yoshida, K. [Tokyo Metropolitan University, Hachioji (Japan); Yusa, Y. [Niigata University, Niigata (Japan)

2015-07-01

The Belle II detector, a follow up of the very successful Belle experiment, is under construction at the SuperKEKB electron–positron collider at KEK in Japan. For the PID system in the forward region of the spectrometer, a proximity-focusing ring-imaging Cherenkov counter with an aerogel radiator is being developed. For the position sensitive photon sensor, a 144-channel Hybrid Avalanche Photo-Detector has been developed with Hamamatsu Photonics K.K. In this report, we describe the specification of the Hybrid Avalanche Photo-Detector and the status of the mass production.

Improved Saturation Performance in High Speed Waveguide Photodetectors at 1.3 ??sing an Asymmetric InA1GaAs/InGaAsP Structure

Science.gov (United States)

Vang, T. A.; Davis, L.; Keo, S.; Forouhar, S. F.

1996-01-01

Waveguide photodetector (WGPD) results have recently been presented demonstrating the very large bandwidth-efficiency product potential of these devices. Improved saturation and linearity characteristics are realized in waveguide p-i-n photodetectors at 1.3 ??y using an asymmetric cladding structure with InA1GaAs/InGaAsP in the anode and InGaAsP in the cathode.

Smart photodetector arrays for error control in page-oriented optical memory

Science.gov (United States)

Schaffer, Maureen Elizabeth

1998-12-01

Page-oriented optical memories (POMs) have been proposed to meet high speed, high capacity storage requirements for input/output intensive computer applications. This technology offers the capability for storage and retrieval of optical data in two-dimensional pages resulting in high throughput data rates. Since currently measured raw bit error rates for these systems fall several orders of magnitude short of industry requirements for binary data storage, powerful error control codes must be adopted. These codes must be designed to take advantage of the two-dimensional memory output. In addition, POMs require an optoelectronic interface to transfer the optical data pages to one or more electronic host systems. Conventional charge coupled device (CCD) arrays can receive optical data in parallel, but the relatively slow serial electronic output of these devices creates a system bottleneck thereby eliminating the POM advantage of high transfer rates. Also, CCD arrays are "unintelligent" interfaces in that they offer little data processing capabilities. The optical data page can be received by two-dimensional arrays of "smart" photo-detector elements that replace conventional CCD arrays. These smart photodetector arrays (SPAs) can perform fast parallel data decoding and error control, thereby providing an efficient optoelectronic interface between the memory and the electronic computer. This approach optimizes the computer memory system by combining the massive parallelism and high speed of optics with the diverse functionality, low cost, and local interconnection efficiency of electronics. In this dissertation we examine the design of smart photodetector arrays for use as the optoelectronic interface for page-oriented optical memory. We review options and technologies for SPA fabrication, develop SPA requirements, and determine SPA scalability constraints with respect to pixel complexity, electrical power dissipation, and optical power limits. Next, we examine data

THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

Energy Technology Data Exchange (ETDEWEB)

Balog, Zoltan; Detre, Örs H.; Bouwmann, Jeroen; Nielbock, Markus; Klaas, Ulrich; Krause, Oliver; Henning, Thomas [Max Planck Institute for Astronomy Königstuhl 17, Heidelberg D-69117 (Germany); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Flaherty, Kevin [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Furlan, Elise [Natinal Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Gutermuth, Rob [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Juhasz, Attila [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands); Bally, John [CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States); Marton, Gabor, E-mail: balog@mpia.de [Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest (Hungary)

2014-07-10

We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.

An improved PIN photodetector with integrated JFET on high-resistivity silicon

International Nuclear Information System (INIS)

Dalla Betta, Gian-Franco; Piemonte, Claudio; Boscardin, Maurizio; Gregori, Paolo; Zorzi, Nicola; Fazzi, Alberto; Pignatel, Giorgio U.

2006-01-01

We report on a PIN photodetector integrated with a Junction Field Effect Transistor (JFET) on a high-resistivity silicon substrate. Owing to a modified fabrication technology, the electrical and noise characteristics of the JFET transistor have been enhanced with respect to the previous versions of the device, allowing the performance to be significantly improved. In this paper, the main design and technological aspects relevant to the proposed structure are addressed and experimental results from the electrical characterization are discussed

Design of a photodetector unit of a new Shashlyk EM calorimeter for COMPASS II

International Nuclear Information System (INIS)

Chirikov-Zorin, I.; Krumshtein, Z.; Olchevski, A.

2015-01-01

A nine-channel photodetector unit with micropixel avalanche photodiodes (MAPD) and precision thermostabilization based on the compact Peltier module was designed and constructed. MAPD-3N with a high pixel density of 1.5·10 4 mm -2 and area 3x3 mm produced by Zecotek were used.

Modeling and simulation of a 3D-CMOS silicon photodetector for low-intensity light detection

Science.gov (United States)

Sabri Alirezaei, Iman; Burte, Edmund P.

2016-03-01

This paper presents a design and simulation of a novel high performance 3D-silicon photodetector for implementing in the low intensity light detection at room temperature (300K). The photodetector is modeled by inspiration of general MEMS fabrication to make a 3D- structure in the silicon substrate using a bulk micromachining process, and based on a complementary metal-oxide semiconductor (CMOS) technology. The design includes a vertical n+/p junction as an optical window for lateral illumination. The simulation is carried out using COMSOL Multiphysics relying on theoretical and physical concepts, and then, the assessment of the results is done by the numerical analysis with SILVACO (Atlas) device simulator. Light is regarded as a monochromatic beam with a wavelength of 633nm that is placed 1μm far from the optical window. The simulation is considered under the reverse bias dc voltage in the steadystate. We present photocurrent-voltage (Iph-V) characteristics under different light intensities (2… 10[mW/cm2]), and dark current-voltage (Id-V) characteristics. Comparative studies of sensitivity dependence on the dopant concentration in the substrate as an intrinsic region are accomplished utilizing two different p-type silicon substrates with 1×1015 [1/cm3] and 4×1012 [1/cm3] doping concentration. Moreover, the sensitivity is evaluated with respect to the active substrate thickness. The simulated results confirmed that the high optical sensitivity of the photodetector with low dark current can be realized in this model.

Solid-state photo-detectors for both CT and PET applications

CERN Document Server

Moraes, Danielle; Jarron, Pierre

2007-01-01

New semiconductor detectors have recently gained a lot of attention for medical applications in general. Advances in CdZnTe-detector arrays might improve both energy resolution and spatial resolution of clinical X-ray systems. Alternative system designs based on TFA technology combining photo-detector arrays with CMOS electronics open a possibility for compact imaging cameras. This scenario allows for the use of alternative materials such as a-Si:H and HgI2 that can be applied alone or integrated with scintillators. Results obtained with such materials are presented.

Random sized plasmonic nanoantennas on Silicon for low-cost broad-band near-infrared photodetection

Science.gov (United States)

Nazirzadeh, Mohammad Amin; Atar, Fatih Bilge; Turgut, Berk Berkan; Okyay, Ali Kemal

2014-01-01

In this work, we propose Silicon based broad-band near infrared Schottky barrier photodetectors. The devices operate beyond 1200 nm wavelength and exhibit photoresponsivity values as high as 3.5 mA/W with a low dark current density of about 50 pA/µm2. We make use of Au nanoislands on Silicon surface formed by rapid thermal annealing of a thin Au layer. Surface plasmons are excited on Au nanoislands and this field localization results in efficient absorption of sub-bandgap photons. Absorbed photons excite the electrons of the metal to higher energy levels (hot electron generation) and the collection of these hot electrons to the semiconductor results in photocurrent (internal photoemission). Simple and scalable fabrication makes these devices suitable for ultra-low-cost NIR detection applications. PMID:25407509

Low Dark-Current, High Current-Gain of PVK/ZnO Nanoparticles Composite-Based UV Photodetector by PN-Heterojunction Control.

Science.gov (United States)

Lee, Sang-Won; Cha, Seung-Hwan; Choi, Kyung-Jae; Kang, Byoung-Ho; Lee, Jae-Sung; Kim, Sae-Wan; Kim, Ju-Seong; Jeong, Hyun-Min; Gopalan, Sai-Anand; Kwon, Dae-Hyuk; Kang, Shin-Won

2016-01-07

We propose a solution-processable ultraviolet (UV) photodetector with a pn-heterojunction hybrid photoactive layer (HPL) that is composed of poly-n-vinylcarbazole (PVK) as a p-type polymer and ZnO nanoparticles (NPs) as an n-type metal oxide. To observe the effective photo-inducing ability of the UV photodetector, we analyzed the optical and electrical properties of HPL which is controlled by the doping concentration of n-type ZnO NPs in PVK matrix. Additionally, we confirmed that the optical properties of HPL dominantly depend on the ZnO NPs from the UV-vis absorption and the photoluminescence (PL) spectral measurements. This HPL can induce efficient charge transfer in the localized narrow pn-heterojunction domain and increases the photocurrent gain. It is essential that proper doping concentration of n-type ZnO NPs in polymer matrix is obtained to improve the performance of the UV photodetector. When the ZnO NPs are doped with the optimized concentration of 3.4 wt.%, the electrical properties of the photocurrent are significantly increased. The ratio of the photocurrent was approximately 10³ higher than that of the dark current.

Low Dark-Current, High Current-Gain of PVK/ZnO Nanoparticles Composite-Based UV Photodetector by PN-Heterojunction Control

Directory of Open Access Journals (Sweden)

Sang-Won Lee

2016-01-01

Full Text Available We propose a solution-processable ultraviolet (UV photodetector with a pn-heterojunction hybrid photoactive layer (HPL that is composed of poly-n-vinylcarbazole (PVK as a p-type polymer and ZnO nanoparticles (NPs as an n-type metal oxide. To observe the effective photo-inducing ability of the UV photodetector, we analyzed the optical and electrical properties of HPL which is controlled by the doping concentration of n-type ZnO NPs in PVK matrix. Additionally, we confirmed that the optical properties of HPL dominantly depend on the ZnO NPs from the UV-vis absorption and the photoluminescence (PL spectral measurements. This HPL can induce efficient charge transfer in the localized narrow pn-heterojunction domain and increases the photocurrent gain. It is essential that proper doping concentration of n-type ZnO NPs in polymer matrix is obtained to improve the performance of the UV photodetector. When the ZnO NPs are doped with the optimized concentration of 3.4 wt.%, the electrical properties of the photocurrent are significantly increased. The ratio of the photocurrent was approximately 103 higher than that of the dark current.

Study of low dimensional SiGe island on Si for potential visible Metal-Semiconductor-Metal photodetector

Science.gov (United States)

Rahim, Alhan Farhanah Abd; Zainal Badri, Nur'Amirah; Radzali, Rosfariza; Mahmood, Ainorkhilah

2017-11-01

In this paper, an investigation of design and simulation of silicon germanium (SiGe) islands on silicon (Si) was presented for potential visible metal semiconductor metal (MSM) photodetector. The characterization of the performances in term of the structural, optical and electrical properties of the structures was analyzed from the simulation results. The project involves simulation using SILVACO Technology Computer Aided Design (TCAD) tools. The different structures of the silicon germanium (SiGe) island on silicon substrate were created, which were large SiGe, small SiGe, combination SiGe and bulk Ge. All the structures were tested for potential Metal Semiconductor Metal (MSM) photodetector. The extracted data such as current versus voltage characteristic, current gain and spectral response were obtained using ATLAS SILVACO tools. The performance of SiGe island structures and bulk Ge on Si substrate as (MSM) photodetector was evaluated by photo and dark current-voltage (I-V) characteristics. It was found that SiGe islands exhibited higher energy band gap compared to bulk Ge. The SiGe islands current-voltage characteristics showed improved current gain compared to bulk Ge. Specifically the enhancement of the islands gain was contributed by the enhanced photo currents and lower dark currents. The spectral responses of the SiGe islands showed peak response at 590 nm (yellow) which is at the visible wavelength. This shows the feasibility of the SiGe islands to be utilized for visible photodetections.

Study of low dimensional SiGe island on Si for potential visible Metal-Semiconductor-Metal photodetector

Directory of Open Access Journals (Sweden)

Abd Rahim Alhan Farhanah

2017-01-01

Full Text Available In this paper, an investigation of design and simulation of silicon germanium (SiGe islands on silicon (Si was presented for potential visible metal semiconductor metal (MSM photodetector. The characterization of the performances in term of the structural, optical and electrical properties of the structures was analyzed from the simulation results. The project involves simulation using SILVACO Technology Computer Aided Design (TCAD tools. The different structures of the silicon germanium (SiGe island on silicon substrate were created, which were large SiGe, small SiGe, combination SiGe and bulk Ge. All the structures were tested for potential Metal Semiconductor Metal (MSM photodetector. The extracted data such as current versus voltage characteristic, current gain and spectral response were obtained using ATLAS SILVACO tools. The performance of SiGe island structures and bulk Ge on Si substrate as (MSM photodetector was evaluated by photo and dark current-voltage (I-V characteristics. It was found that SiGe islands exhibited higher energy band gap compared to bulk Ge. The SiGe islands current-voltage characteristics showed improved current gain compared to bulk Ge. Specifically the enhancement of the islands gain was contributed by the enhanced photo currents and lower dark currents. The spectral responses of the SiGe islands showed peak response at 590 nm (yellow which is at the visible wavelength. This shows the feasibility of the SiGe islands to be utilized for visible photodetections.

UV-Assisted Photochemical Synthesis of Reduced Graphene Oxide/ZnO Nanowires Composite for Photoresponse Enhancement in UV Photodetectors

Directory of Open Access Journals (Sweden)

Changsong Chen

2018-01-01

Full Text Available The weak photon absorption and high recombination rate of electron-hole pairs in disordered zinc oxide nanowires (ZNWs limit its application in UV photodetection. This limitation can be overcome by introducing graphene sheets to the ZNWs. Herein we report a high-performance photodetector based on one-dimensional (1D wide band-gap semiconductor disordered ZNWs composited with reduced graphene oxide (RGO for ultraviolet (UV photoresponse enhancement. The RGO/ZNWs composites have been successfully synthetized through UV-assisted photochemical reduction of GO in ZNWs suspension. The material characterizations in morphology, Raman scattering, and Ultraviolet-visible light absorption verified the formation of graphene sheets attached in ZNWs network and the enhancement of UV absorption due to the introduction of graphene. In comparison with photodetectors based on pure ZNWs, the photodetectors based on RGO/ZNWs composite exhibit enhanced photoresponse with photocurrent density of 5.87 mA·cm−2, on/off current ratio of 3.01 × 104, and responsivity of 1.83 A·W−1 when a UV irradiation of 3.26 mW·cm−2 and 1.0 V bias were used. Theory analysis is also presented to get insight into the inherent mechanisms of separation and transportation of photo-excited carriers in RGO/ZNWs composite.

UV-Assisted Photochemical Synthesis of Reduced Graphene Oxide/ZnO Nanowires Composite for Photoresponse Enhancement in UV Photodetectors.

Science.gov (United States)

Chen, Changsong; Zhou, Peng; Wang, Na; Ma, Yang; San, Haisheng

2018-01-05

The weak photon absorption and high recombination rate of electron-hole pairs in disordered zinc oxide nanowires (ZNWs) limit its application in UV photodetection. This limitation can be overcome by introducing graphene sheets to the ZNWs. Herein we report a high-performance photodetector based on one-dimensional (1D) wide band-gap semiconductor disordered ZNWs composited with reduced graphene oxide (RGO) for ultraviolet (UV) photoresponse enhancement. The RGO/ZNWs composites have been successfully synthetized through UV-assisted photochemical reduction of GO in ZNWs suspension. The material characterizations in morphology, Raman scattering, and Ultraviolet-visible light absorption verified the formation of graphene sheets attached in ZNWs network and the enhancement of UV absorption due to the introduction of graphene. In comparison with photodetectors based on pure ZNWs, the photodetectors based on RGO/ZNWs composite exhibit enhanced photoresponse with photocurrent density of 5.87 mA·cm -2 , on/off current ratio of 3.01 × 10⁴, and responsivity of 1.83 A·W -1 when a UV irradiation of 3.26 mW·cm -2 and 1.0 V bias were used. Theory analysis is also presented to get insight into the inherent mechanisms of separation and transportation of photo-excited carriers in RGO/ZNWs composite.

A fast and zero-biased photodetector based on GaTe-InSe vertical 2D p-n heterojunction

Science.gov (United States)

Feng, W.; Jin, Z.; Yuan, J.; Zhang, J.; Jia, S.; Dong, L.; Yoon, J.; Zhou, L.; Vajtai, R.; Tour, J. M.; Ajayan, P. M.; Hu, P.; Lou, J.

2018-04-01

p-n junctions serve as the building blocks for fundamental semiconductor devices, such as solar cells, light-emitting diodes (LEDs) and photodetectors. With recent studies unveiling the excellent optoelectronic properties of two-dimensional (2D) semiconductors, they are considered to be superb candidates for high performance p-n junctions. Here, we fabricate a vertical GaTe-InSe van der Waals (vdWs) p-n heterojunction by a PDMS-assisted transfer technique without etching. The fabricated p-n heterojunction shows gate-tunable current-rectifying behavior with a rectification factor reaching 1000. In addition, it features fast photodetection under zero bias as well as a high power conversion efficiency (PCE). Under 405 nm laser excitation, the zero-biased photodetector shows a high responsivity of 13.8 mA W-1 as well as a high external quantum efficiency (EQE) of 4.2%. Long-term stability is also observed and a response time of 20 µs is achieved due to stable and fast carrier transit through the built-in electric field in the depletion region. Fast and efficient charge separation in the vertical 2D p-n junction paves the way for developing 2D photodetectors with zero dark current, high speed and low power consumption.

A fully-integrated 12.5-Gb/s 850-nm CMOS optical receiver based on a spatially-modulated avalanche photodetector.

Science.gov (United States)

Lee, Myung-Jae; Youn, Jin-Sung; Park, Kang-Yeob; Choi, Woo-Young

2014-02-10

We present a fully integrated 12.5-Gb/s optical receiver fabricated with standard 0.13-µm complementary metal-oxide-semiconductor (CMOS) technology for 850-nm optical interconnect applications. Our integrated optical receiver includes a newly proposed CMOS-compatible spatially-modulated avalanche photodetector, which provides larger photodetection bandwidth than previously reported CMOS-compatible photodetectors. The receiver also has high-speed CMOS circuits including transimpedance amplifier, DC-balanced buffer, equalizer, and limiting amplifier. With the fabricated optical receiver, detection of 12.5-Gb/s optical data is successfully achieved at 5.8 pJ/bit. Our receiver achieves the highest data rate ever reported for 850-nm integrated CMOS optical receivers.

Evaluation of different photodetector types for an ILC polarimeter

International Nuclear Information System (INIS)

Helebrant, Christian

2009-01-01

At the International Linear Collider (ILC) (ILC Reference Design Report, 2007 ) the polarization of the electron and positron beams needs to be measured with as yet unequaled precision of ΔP/P∼0.25%. The key element of the polarimeter will be the precise detection of Cherenkov light from Compton scattered electrons. The poster ) deals with the choice of a suitable photodetector (PD). In a recently assembled test facility various types of PDs have been checked. Results are presented with a special focus on the linearity of the device, since this is expected to be the limiting factor on the precision of the polarization measurement at the ILC.

Progress in the realization of a silicon-CNT photodetector

Energy Technology Data Exchange (ETDEWEB)

Aramo, C., E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, A. [CNR-SPIN U.O.S. di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Castrucci, P. [Dipartimento di Fisica, Universita degli Studi di Roma Tor Vergata,Via della Ricerca Scientifica 1, 00133 Roma (Italy); Cilmo, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); De Crescenzi, M. [Dipartimento di Fisica, Universita degli Studi di Roma Tor Vergata,Via della Ricerca Scientifica 1, 00133 Roma (Italy); Fiandrini, E. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universita degli Studi di Perugia, PiazzaUniversita 1, 06100 Perugia (Italy); Guarino, F. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Grossi, V. [Dipartimento di Fisica, Universita degli Studi dell' Aquila, Via Vetoio 10, 67100 Coppito, L' Aquila (Italy); Nappi, E. [INFN, Sezione di Bari, e Dipartimento di Fisica, Universita degli Studi di Bari, Via Amendola 173, 70126 Bari (Italy); Passacantando, M. [Dipartimento di Fisica, Universita degli Studi dell' Aquila, Via Vetoio 10, 67100 Coppito, L' Aquila (Italy); Pignatel, G. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universita degli Studi di Perugia, PiazzaUniversita 1, 06100 Perugia (Italy); and others

2012-12-11

The realization of a Silicon Carbon Nanotube heterojuntion opens the door to a new generation of photodetectors (Si-CNT detector) based on the coupling between this two materials. In particular the growth of Multiwall Carbon Nanotubes on the surface of a n-doped silicon substrate results on a Schottky diode junction with precise rectifying characteristics. The obtained device presents a low dark current, high efficiency in the photoresponsivity, high linearity and a wide stability range. The junction barrier is about 3.5 V in reverse polarity with a breakdown limit at more than 100 V. The spectral behavior reflects the silicon spectral range with a maximum at about 880 nm.

Sub-10ps monolithic and low-power photodetector readout

International Nuclear Information System (INIS)

Varner, Gary S.; Ruckman, Larry L.

2009-01-01

Recent advances in photon detectors have resulted in high-density imaging arrays that offer many performance and cost advantages. In particular, the excellent transit time spread of certain devices show promise to provide tangible benefits in applications such as Positron Emission Tomography (PET). Meanwhile, high-density, high-performance readout techniques have not kept on pace for exploiting these developments. Photodetector readout for next generation high event rate particle identification and time-resolved PET requires a highly-integrated, low-power, and cost-effective readout technique. We propose fast waveform sampling as a method that meets these criteria and demonstrate that sub-10ps resolution can be obtained for an existing device

Sub-10ps monolithic and low-power photodetector readout

Energy Technology Data Exchange (ETDEWEB)

Varner, Gary S.; Ruckman, Larry L.

2009-02-20

Recent advances in photon detectors have resulted in high-density imaging arrays that offer many performance and cost advantages. In particular, the excellent transit time spread of certain devices show promise to provide tangible benefits in applications such as Positron Emission Tomography (PET). Meanwhile, high-density, high-performance readout techniques have not kept on pace for exploiting these developments. Photodetector readout for next generation high event rate particle identification and time-resolved PET requires a highly-integrated, low-power, and cost-effective readout technique. We propose fast waveform sampling as a method that meets these criteria and demonstrate that sub-10ps resolution can be obtained for an existing device.

High-Responsivity Graphene-Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit.

Science.gov (United States)

Shiue, Ren-Jye; Gao, Yuanda; Wang, Yifei; Peng, Cheng; Robertson, Alexander D; Efetov, Dmitri K; Assefa, Solomon; Koppens, Frank H L; Hone, James; Englund, Dirk

2015-11-11

Graphene and other two-dimensional (2D) materials have emerged as promising materials for broadband and ultrafast photodetection and optical modulation. These optoelectronic capabilities can augment complementary metal-oxide-semiconductor (CMOS) devices for high-speed and low-power optical interconnects. Here, we demonstrate an on-chip ultrafast photodetector based on a two-dimensional heterostructure consisting of high-quality graphene encapsulated in hexagonal boron nitride. Coupled to the optical mode of a silicon waveguide, this 2D heterostructure-based photodetector exhibits a maximum responsivity of 0.36 A/W and high-speed operation with a 3 dB cutoff at 42 GHz. From photocurrent measurements as a function of the top-gate and source-drain voltages, we conclude that the photoresponse is consistent with hot electron mediated effects. At moderate peak powers above 50 mW, we observe a saturating photocurrent consistent with the mechanisms of electron-phonon supercollision cooling. This nonlinear photoresponse enables optical on-chip autocorrelation measurements with picosecond-scale timing resolution and exceptionally low peak powers.

A Comprehensive Review of Semiconductor Ultraviolet Photodetectors: From Thin Film to One-Dimensional Nanostructures

Directory of Open Access Journals (Sweden)

Liwen Sang

2013-08-01

Full Text Available Ultraviolet (UV photodetectors have drawn extensive attention owing to their applications in industrial, environmental and even biological fields. Compared to UV-enhanced Si photodetectors, a new generation of wide bandgap semiconductors, such as (Al, In GaN, diamond, and SiC, have the advantages of high responsivity, high thermal stability, robust radiation hardness and high response speed. On the other hand, one-dimensional (1D nanostructure semiconductors with a wide bandgap, such as β-Ga2O3, GaN, ZnO, or other metal-oxide nanostructures, also show their potential for high-efficiency UV photodetection. In some cases such as flame detection, high-temperature thermally stable detectors with high performance are required. This article provides a comprehensive review on the state-of-the-art research activities in the UV photodetection field, including not only semiconductor thin films, but also 1D nanostructured materials, which are attracting more and more attention in the detection field. A special focus is given on the thermal stability of the developed devices, which is one of the key characteristics for the real applications.

Low-temperature processed ZnO and CdS photodetectors deposited by pulsed laser deposition

International Nuclear Information System (INIS)

Hernandez-Como, N; Moreno, S; Mejia, I; Quevedo-Lopez, M A

2014-01-01

UV-VIS photodetectors using an interdigital configuration, with zinc oxide (ZnO) and cadmium sulfide (CdS) semiconductors deposited by pulsed laser deposition, were fabricated with a maximum processing temperature of 100 °C. Without any further post-growth annealing, the photodetectors are compatible with flexible and transparent substrates. Aluminum (Al) and indium tin oxide (ITO) were investigated as contacts. Focusing on underwater communications, the impact of metal contact (ITO versus Al) was investigated to determine the maximum responsivity using a laser with a 405 nm wavelength. As expected, the responsivity increases for reduced metal finger separation. This is a consequence of reduced carrier transit time for shorter finger separation. For ITO, the highest responsivities for both films (ZnO and CdS) were ∼3 A W −1 at 5 V. On the other hand, for Al contacts, the maximum responsivities at 5 V were ∼0.1 A W −1 and 0.7 A W −1 for CdS and ZnO, respectively. (paper)

Au plasmon enhanced high performance β-Ga2O3 solar-blind photo-detector

Directory of Open Access Journals (Sweden)

Yuehua An

2016-02-01

Full Text Available Surface plasmon polariton (SPP is electro-magnetic wave coupled to free electron oscillations near the surface of metal, and has been used to improve the photoelectric properties in many optoelectronic devices. In the present study, the Au nanoparticles (NPs/β-Ga2O3 composite thin film was fabricated through depositing Au ultra-thin film on the β-Ga2O3 thin film followed by post-thermal treatment. Compared to bare β-Ga2O3 thin film, a significant absorption around 510 nm, which is attributed to SPP of Au NPs, was observed in the UV–vis spectrum of Au NPs/β-Ga2O3 composite thin film. The results showed that the photoresponse of Au NPs/Ga2O3 photodetector illuminated under 254 nm+532 nm light was much higher than that illuminated under 254 nm light, indicating an enhancement of photoelectric property for the solar-blind photodetector based on β-Ga2O3 thin film.

High-Performance solar-blind flexible Deep-UV photodetectors based on quantum dots synthesized by femtosecond-laser ablation

KAUST Repository

Mitra, Somak; Aravindh, Assa; Das, Gobind; Pak, Yusin; Ajia, Idris A.; Loganathan, Kalaivanan; Di Fabrizio, Enzo M.; Roqan, Iman S.

2018-01-01

-performance flexible DUV photodetectors operating at ambient conditions based on quantum dots (QDs) synthesized by femtosecond-laser ablation in liquid (FLAL) technique. Our method is facile without complex chemical procedures, which allows large-scale cost

Electro-optical study of nanoscale Al-Si-truncated conical photodetector with subwavelength aperture

Science.gov (United States)

Karelits, Matityahu; Mandelbaum, Yaakov; Chelly, Avraham; Karsenty, Avi

2017-10-01

A type of silicon photodiode has been designed and simulated to probe the optical near field and detect evanescent waves. These waves convey subwavelength resolution. This photodiode consists of a truncated conical shaped, silicon Schottky diode having a subwavelength aperture of 150 nm. Electrical and electro-optical simulations have been conducted. These results are promising toward the fabrication of a new generation of photodetector devices.

Application of DIRI dynamic infrared imaging in reconstructive surgery

Science.gov (United States)

Pawlowski, Marek; Wang, Chengpu; Jin, Feng; Salvitti, Matthew; Tenorio, Xavier

2006-04-01

We have developed the BioScanIR System based on QWIP (Quantum Well Infrared Photodetector). Data collected by this sensor are processed using the DIRI (Dynamic Infrared Imaging) algorithms. The combination of DIRI data processing methods with the unique characteristics of the QWIP sensor permit the creation of a new imaging modality capable of detecting minute changes in temperature at the surface of the tissue and organs associated with blood perfusion due to certain diseases such as cancer, vascular disease and diabetes. The BioScanIR System has been successfully applied in reconstructive surgery to localize donor flap feeding vessels (perforators) during the pre-surgical planning stage. The device is also used in post-surgical monitoring of skin flap perfusion. Since the BioScanIR is mobile; it can be moved to the bedside for such monitoring. In comparison to other modalities, the BioScanIR can localize perforators in a single, 20 seconds scan with definitive results available in minutes. The algorithms used include (FFT) Fast Fourier Transformation, motion artifact correction, spectral analysis and thermal image scaling. The BioScanIR is completely non-invasive and non-toxic, requires no exogenous contrast agents and is free of ionizing radiation. In addition to reconstructive surgery applications, the BioScanIR has shown promise as a useful functional imaging modality in neurosurgery, drug discovery in pre-clinical animal models, wound healing and peripheral vascular disease management.

Air-stable, solution-processed oxide p-n heterojunction ultraviolet photodetector.

Science.gov (United States)

Kim, Do Young; Ryu, Jiho; Manders, Jesse; Lee, Jaewoong; So, Franky

2014-02-12

Air-stable solution processed all-inorganic p-n heterojunction ultraviolet photodetector is fabricated with a high gain (EQE, 25 300%). Solution-processed NiO and ZnO films are used as p-type and n-type ultraviolet sensitizing materials, respectively. The high gain in the detector is due to the interfacial trap-induced charge injection that occurs at the ITO/NiO interface by photogenerated holes trapped in the NiO film. The gain of the detector is controlled by the post-annealing temperature of the solution-processed NiO films, which are studied by X-ray photoelectron spectroscopy (XPS).

Long-wavelength photonic integrated circuits and avalanche photodetectors

Science.gov (United States)

Tsou, Yi-Jen D.; Zaytsev, Sergey; Pauchard, Alexandre; Hummel, Steve; Lo, Yu-Hwa

2001-10-01

Fast-growing internet traffic volume require high data communication bandwidth over longer distances. Access network bottlenecks put pressure on short-range (SR) telecommunication systems. To effectively address these datacom and telecom market needs, low-cost, high-speed laser modules at 1310 to 1550 nm wavelengths and avalanche photodetectors are required. The great success of GaAs 850nm VCSEls for Gb/s Ethernet has motivated efforts to extend VCSEL technology to longer wavelengths in the 1310 and 1550 nm regimes. However, the technological challenges associated with materials for long wavelength VCSELs are tremendous. Even with recent advances in this area, it is believed that significant additional development is necessary before long wavelength VCSELs that meet commercial specifications will be widely available. In addition, the more stringent OC192 and OC768 specifications for single-mode fiber (SMF) datacom may require more than just a long wavelength laser diode, VCSEL or not, to address numerous cost and performance issues. We believe that photonic integrated circuits (PICs), which compactly integrate surface-emitting lasers with additional active and passive optical components with extended functionality, will provide the best solutions to today's problems. Photonic integrated circuits have been investigated for more than a decade. However, they have produced limited commercial impact to date primarily because the highly complicated fabrication processes produce significant yield and device performance issues. In this presentation, we will discuss a new technology platform of InP-based PICs compatible with surface-emitting laser technology, as well as a high data rate externally modulated laser module. Avalanche photodetectors (APDs) are the key component in the receiver to achieve high data rate over long transmission distance because of their high sensitivity and large gain- bandwidth product. We have used wafer fusion technology to achieve In

A fast position sensitive photodetector based on a CsI reflective photocathode

International Nuclear Information System (INIS)

Arnold, R.; Christophel, E.; Guyonnet, J.L.

1991-01-01

A fast detector was built for UV photon detection that depends on a CsI sensitized pad cathode. The rapidity of the detector is compared with that of a more classical chamber filled with photosensitive gases such as TEA or TMAE. Estimates of the quantum yield of the photocathode at 160 and 200 nm are given. The performances obtained make it a good photodetector candidate to be operated at high luminosity accelerators. (author) 7 refs., 19 figs

Infrared detectors and emitters on the basis of semiconductor quantum structures

International Nuclear Information System (INIS)

Kruck, P. R.

1997-08-01

Intersubband transitions in Si/SiGe and GaAs/AlGaAs semiconductor quantum structures have been investigated with respect to possible application as infrared detectors and emitters. Investigation of the polarization dependence of subband absorption in Si/SiGe quantum wells shows both transverse magnetic and transverse electric polarized excitations. Intersubband transitions to several excited states are identified by comparison with self-consistent Luttinger-Kohn type calculations. On the basis of these investigations a quantum well infrared photodetector operating between 3 and 8 μm with a detectivity as high as D*=2 x 10 10 cm Hz 1/2 W -1 under normal incidence illumination and at an operating temperature of T=77K is realized. The polarization dependence of the photoconductivity shows the importance of both the absorption and the vertical transport properties of the photoexcited carriers for the detection mechanism. On the basis of the GaAs/AlGaAs material system a unipolar quantum cascade light emitting diode (LED) has been realized. The LED operates at a wavelength of 6.9 μm. A detailed analysis of the electroluminescence spectra shows a linewidth as narrow as 14 meV at cryogenic temperatures, increasing to 20 meV at room temperature. For typical drive-current densities of 1 kA/cm 2 the optical output power lies in the ten nanowatt range. (author)

Ultraviolet photodetectors made from SnO2 nanowires

International Nuclear Information System (INIS)

Wu, Jyh-Ming; Kuo, Cheng-Hsiang

2009-01-01

SnO 2 nanowires can be synthesized on alumina substrates and formed into an ultraviolet (UV) photodetector. The photoelectric current of the SnO 2 nanowires exhibited a rapid photo-response as a UV lamp was switched on and off. The ratio of UV-exposed current to dark current has been investigated. The SnO 2 nanowires were synthesized by a vapor-liquid-solid process at a temperature of 900 o C. It was found that the nanowires were around 70-100 nm in diameter and several hundred microns in length. High-resolution transmission electron microscopy (HRTEM) image indicated that the nanowires grew along the [200] axis as a single crystallinity. Cathodoluminescence (CL), thin-film X-ray diffractometry, and X-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized nanowires.

GaN/AlGaN-based UV photodetectors with performances exceeding the PMTS

OpenAIRE

Tut, Turgut

2008-01-01

Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent University, 2008. Thesis (Ph.D.) -- Bilkent University, 2008. Includes bibliographical references leaves 73-80. The recent developments in high Al-content AlxGa1−xN material growth technology made it possible to fabricate high performance solar-blind photodetectors operating in the ultraviolet (UV) spectral region with improved receiver sensitivity, low noise, low dark current density,...

Fabrication of GaInPSb quaternary alloy nanowires and its room temperature electrical properties

Energy Technology Data Exchange (ETDEWEB)

Xu, Yadan; Ma, Liang; Li, Dan; Yang, Yankun; Wan, Qiang [Hunan University, School of Physics and Electronics, Changsha, Hunan (China); Liu, Ruping [Beijing Institute of Graphic Communication, Beijing (China); Dai, Guozhang [Central South University, School of Physics and Electronics, Changsha, Hunan (China)

2017-01-15

GaInPSb quaternary alloy nanowires were first synthesized via a simple chemical vapor deposition method. The synthesized nanowires' length can reach up to 20 μm and diameter ranging from 50 to 100 nm. Raman measurements and high-resolution transmission electron microscopy image illustrate that the as-grown nanowires have a high crystallinity. Room temperature near-infrared photodetector based on as-prepared GaInPSb nanowires was also built for the first time. It shows a good contact with the electrode, and the device has a strong light response to light illumination. This novel near-infrared photodetector may find promising applications in integrated infrared photodetection, information communication, and processing. (orig.)

Graphene photodetectors with a bandwidth  >76 GHz fabricated in a 6″ wafer process line

Science.gov (United States)

Schall, Daniel; Porschatis, Caroline; Otto, Martin; Neumaier, Daniel

2017-03-01

In recent years, the data traffic has grown exponentially and the forecasts indicate a huge market that could be addressed by communication infrastructure and service providers. However, the processing capacity, space, and energy consumption of the available technology is a serious bottleneck for the exploitation of these markets. Chip-integrated optical communication systems hold the promise of significantly improving these issues related to the current technology. At the moment, the answer to the question which material is best suited for ultrafast chip integrated communication systems is still open. In this manuscript we report on ultrafast graphene photodetectors with a bandwidth of more than 76 GHz well suitable for communication links faster than 100 GBit s-1 per channel. We extract an upper value of 7.2 ps for the timescale in which the bolometric photoresponse in graphene is generated. The photodetectors were fabricated on 6″ silicon-on-insulator wafers in a semiconductor pilot line, demonstrating the scalable fabrication of high-performance graphene based devices.

Radiometric characterization of type-II InAs/GaSb superlattice (t2sl) midwave infrared photodetectors and focal plane arrays

Science.gov (United States)

Nghiem, Jean; Giard, E.; Delmas, M.; Rodriguez, J. B.; Christol, P.; Caes, M.; Martijn, H.; Costard, E.; Ribet-Mohamed, I.

2017-09-01

In recent years, Type-II InAs/GaSb superlattice (T2SL) has emerged as a new material technology suitable for high performance infrared (IR) detectors operating from Near InfraRed (NIR, 2-3μm) to Very Long Wavelength InfraRed (LWIR, λ > 15μm) wavelength domains. To compare their performances with well-established IR technologies such as MCT, InSb or QWIP cooled detectors, specific electrical and radiometric characterizations are needed: dark current, spectral response, quantum efficiency, temporal and spatial noises, stability… In this paper, we first present quantum efficiency measurements performed on T2SL MWIR (3-5μm) photodiodes and on one focal plane array (320x256 pixels with 30μm pitch, realized in the scope of a french collaboration ). Different T2SL structures (InAs-rich versus GaSb-rich) with the same cutoff wavelength (λc= 5μm at 80K) were studied. Results are analysed in term of carrier diffusion length in order to define the optimum thickness and type of doping of the absorbing zone. We then focus on the stability over time of a commercial T2SL FPA (320x256 pixels with 30μm pitch), measuring the commonly used residual fixed pattern noise (RFPN) figure of merit. Results are excellent, with a very stable behaviour over more than 3 weeks, and less than 10 flickering pixels, possibly giving access to long-term stability of IR absolute calibration.

Low-Voltage High-Performance UV Photodetectors: An Interplay between Grain Boundaries and Debye Length.

Science.gov (United States)

Bo, Renheng; Nasiri, Noushin; Chen, Hongjun; Caputo, Domenico; Fu, Lan; Tricoli, Antonio

2017-01-25

Accurate detection of UV light by wearable low-power devices has many important applications including environmental monitoring, space to space communication, and defense. Here, we report the structural engineering of ultraporous ZnO nanoparticle networks for fabrication of very low-voltage high-performance UV photodetectors. A record high photo- to dark-current ratio of 3.3 × 10 5 and detectivity of 3.2 × 10 12 Jones at an ultralow operation bias of 2 mV and low UV-light intensity of 86 μW·cm -2 are achieved by controlling the interplay between grain boundaries and surface depletion depth of ZnO nanoscale semiconductors. An optimal window of structural properties is determined by varying the particle size of ultraporous nanoparticle networks from 10 to 42 nm. We find that small electron-depleted nanoparticles (≤40 nm) are necessary to minimize the dark-current; however, the rise in photocurrent is tampered with decreasing particle size due to the increasing density of grain boundaries. These findings reveal that nanoparticles with a size close to twice their Debye length are required for high photo- to dark-current ratio and detectivity, while further decreasing their size decreases the photodetector performance.

Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

International Nuclear Information System (INIS)

Shasti, M.; Mortezaali, A.; Dariani, R. S.

2015-01-01

In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism

Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis

Energy Technology Data Exchange (ETDEWEB)

Shasti, M.; Mortezaali, A., E-mail: mortezaali@alzahra.ac.ir; Dariani, R. S. [Department of Physics, Alzahra University, Tehran 1993893973 (Iran, Islamic Republic of)

2015-01-14

In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

ZnO quantum dot-doped graphene/h-BN/GaN-heterostructure ultraviolet photodetector with extremely high responsivity

Science.gov (United States)

Lu, Yanghua; Wu, Zhiqian; Xu, Wenli; Lin, Shisheng

2016-12-01

A ZnO quantum dot photo-doped graphene/h-BN/GaN-heterostructure ultraviolet photodetector with extremely high responsivity of more than 1915 A W-1 and detectivity of more than 1.02 × 1013 Jones (Jones = cm Hz1/2 W-1) has been demonstrated. The interfaced h-BN layer increases the barrier height at the graphene/GaN heterojunction, which decreases the dark current and improves the on/off current ratio of the device. The photo-doping effect increases the barrier height and carrier concentration at the graphene/h-BN/GaN heterojunction, thus the responsivity is improved from 1473 A W-1 to 1915 A W-1 and the detectivity is improved from 5.8 × 1012 to 1.0 × 1013 Jones. Moreover, all of the responsivity and detectivity values are the highest values among all the graphene-based ultraviolet photodetectors.

Ion implantation enhanced metal-Si-metal photodetectors

Science.gov (United States)

Sharma, A. K.; Scott, K. A. M.; Brueck, S. R. J.; Zolper, J. C.; Myers, D. R.

1994-05-01

The quantum efficiency and frequency response of simple Ni-Si-Ni metal-semiconductor-metal (MSM) photodetectors at long wavelengths are significantly enhanced with a simple, ion-implantation step to create a highly absorbing region approx. 1 micron below the Si surface. The internal quantum efficiency is improved by a factor of approx. 3 at 860 nm (to 64%) and a full factor of ten at 1.06 microns (to 23%) as compared with otherwise identical unimplanted devices. Dark currents are only slightly affected by the implantation process and are as low as 630 pA for a 4.5-micron gap device at 10-V bias. Dramatic improvement in the impulse response is observed, 100 ps vs. 600 ps, also at 10-V bias and 4.5-micron gap, due to the elimination of carrier diffusion tails in the implanted devices. Due to its planar structure, this device is fully VLSI compatible. Potential applications include optical interconnections for local area networks and multi-chip modules.

The design of a photodetector unit of a new Shashlyk EM calorimeter for COMPASS II

Energy Technology Data Exchange (ETDEWEB)

Chirikov-Zorin, I., E-mail: chirikov@nusun.jinr.ru; Krumshtein, Z.; Olchevski, A.

2016-07-11

A nine-channel photodetector unit with micropixel avalanche photodiodes (MAPD) and precision thermostabilization based on the compact Peltier module is designed and constructed. MAPD-3N with a high pixel density of 15,000 per square mm and area 3×3 mm{sup 2} produced by Zecotek were used.

Intelligent Front-end Electronics for Silicon photodetectors (IFES)

Energy Technology Data Exchange (ETDEWEB)

Sauerzopf, Clemens, E-mail: clemens.sauerzopf@oeaw.ac.at; Gruber, Lukas; Suzuki, Ken; Zmeskal, Johann; Widmann, Eberhard

2016-05-21

While high channel density can be easily achieved for big experiments using custom made microchips, providing something similar for small and medium size experiments imposes a challenge. Within this work we describe a novel and cost effective solution to operate silicon photodetectors such as silicon photo multipliers (SiPM). The IFES modules provide the bias voltage for the detectors, a leading edge discriminator featuring time over threshold and a differential amplifier, all on one printed circuit board. We demonstrate under realistic conditions that the module is usable for high resolution timing measurements exploiting both charge and time information. Furthermore we show that the modules can be easily used in larger detector arrays. All in all this confirms that the IFES modules are a viable option for a broad range of experiments if cost-effectiveness and small form factor are required.

Intelligent Front-end Electronics for Silicon photodetectors (IFES)

Science.gov (United States)

Sauerzopf, Clemens; Gruber, Lukas; Suzuki, Ken; Zmeskal, Johann; Widmann, Eberhard

2016-05-01

While high channel density can be easily achieved for big experiments using custom made microchips, providing something similar for small and medium size experiments imposes a challenge. Within this work we describe a novel and cost effective solution to operate silicon photodetectors such as silicon photo multipliers (SiPM). The IFES modules provide the bias voltage for the detectors, a leading edge discriminator featuring time over threshold and a differential amplifier, all on one printed circuit board. We demonstrate under realistic conditions that the module is usable for high resolution timing measurements exploiting both charge and time information. Furthermore we show that the modules can be easily used in larger detector arrays. All in all this confirms that the IFES modules are a viable option for a broad range of experiments if cost-effectiveness and small form factor are required.

Performance Simulation of Unipolar InAs/InAs1-x Sb x Type-II Superlattice Photodetector

Science.gov (United States)

Singh, Anand; Pal, Ravinder

2018-05-01

This paper reports performance simulation of a unipolar tunable band gap InAs-InAsSb type-II superlattice (T2SL) infrared photodetector. The generation-recombination and surface leakage currents limit the performance of T2SL photodiodes. Unipolar nBn device design incorporating a suitable barrier layer in the diode structure is taken to suppress the Auger recombination and tunneling currents. At low reverse bias, the generation-recombination current is negligible in the absence of a depletion region, but the dark current is dominated by the diffusion current at higher operation temperatures. The composition, band alignment, barrier width, doping level and thickness of the absorber region are optimized here to achieve low dark current and high quantum efficiency at elevated operating temperatures. Thin unipolar T2SL absorbers are placed in a resonant cavity to enhance photon-material interaction, thus allowing complete absorption in a thinner detector element. It leads to the reduction in the detector volume for lower dark current without affecting the quantum efficiency. It shows an improvement in the quantum efficiency and reduction in the dark current. Dark current density ˜ 10-5 A/cm2 is achievable with low absorber thickness of 2 μm and effective lifetime of 250 ns in the InAs/InAs0.6Sb0.4/B-AlAs1-x Sb x long wave length T2SL detector at 110 K.

Packaging of photodetector modules for 100 Gbit/s applications using electromagnetic simulations

DEFF Research Database (Denmark)

Jiang, Chenhui; Krozer, Viktor; Bach, H.-G.

2009-01-01

In this paper we demonstrate ultra-broadband packaging and interconnection designs for photodetector (PD) modules for 100 Gbit/s data transmission applications. The design of packaging and interconnection structures is based on accurate and reliable 3D electromagnetic (EM) simulations. Mode...... conversion loss due to mode mismatch is identified as the dominant effect of limiting bandwidth of packaged modules. Finally, PD chips are successfully packaged by using wire-bonding technology and conventional coplanar waveguide (CPW) for avoiding mode mismatch. The new packaged PD module demonstrates...

Wave study of compound eyes for efficient infrared detection

Science.gov (United States)

Kilinc, Takiyettin Oytun; Hayran, Zeki; Kocer, Hasan; Kurt, Hamza

2017-08-01

Improving sensitivity in the infrared spectrum is a challenging task. Detecting infrared light over a wide bandwidth and at low power consumption is very important. Novel solutions can be acquired by mimicking biological eyes such as compound eye with many individual lenses inspired from the nature. The nature provides many ingenious approaches of sensing and detecting the surrounding environment. Even though compound eye consists of small optical units, it can detect wide-angle electromagnetic waves and it has high transmission and low reflection loss. Insects have eyes that are superior compared to human eyes (single-aperture eyes) in terms of compactness, robustness, wider field of view, higher sensitivity of light intensity and being cheap vision systems. All these desired properties are accompanied by an important drawback: lower spatial resolution. The first step to investigate the feasibility of bio-inspired optics in photodetectors is to perform light interaction with the optical system that gather light and detect it. The most common method used in natural vision systems is the ray analysis. Light wave characteristics are not taken into consideration in such analyses, such as the amount of energy at the focal point or photoreceptor site, the losses caused by reflection at the interfaces and absorption cannot be investigated. In this study, we present a bio-inspired optical detection system investigated by wave analysis. We numerically model the wave analysis based on Maxwell equations from the viewpoint of efficient light detection and revealing the light propagation after intercepting the first interface of the eye towards the photoreceptor site.

ZnO quantum dot-doped graphene/h-BN/GaN-heterostructure ultraviolet photodetector with extremely high responsivity.

Science.gov (United States)

Lu, Yanghua; Wu, Zhiqian; Xu, Wenli; Lin, Shisheng

2016-12-02

A ZnO quantum dot  photo-doped graphene/h-BN/GaN-heterostructure ultraviolet photodetector with extremely high responsivity of more than 1915 A W -1 and detectivity of more than 1.02 × 10 13 Jones (Jones = cm Hz 1/2 W -1 ) has been demonstrated. The interfaced h-BN layer increases the barrier height at the graphene/GaN heterojunction, which decreases the dark current and improves the on/off current ratio of the device. The photo-doping effect increases the barrier height and carrier concentration at the graphene/h-BN/GaN heterojunction, thus the responsivity is improved from 1473 A W -1 to 1915 A W -1 and the detectivity is improved from 5.8 × 10 12 to 1.0 × 10 13 Jones. Moreover, all of the responsivity and detectivity values are the highest values among all the graphene-based ultraviolet photodetectors.

High-performance broadband photodetector using solution-processible PbSe-TiO(2)-graphene hybrids.

Science.gov (United States)

Manga, Kiran Kumar; Wang, Junzhong; Lin, Ming; Zhang, Jie; Nesladek, Milos; Nalla, Venkatram; Ji, Wei; Loh, Kian Ping

2012-04-03

Highly sensitive, multicomponent broadband photodetector devices are made from PbSe/graphene/TiO(2). TiO(2) and PbSe nanoparticles act as light harvesting photoactive materials from the UV to IR regions of the electromagnetic spectrum, while the graphene acts as a charge collector for both photogenerated holes and electrons under an applied electric field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphene photodetectors with a bandwidth  >76 GHz fabricated in a 6″ wafer process line

International Nuclear Information System (INIS)

Schall, Daniel; Porschatis, Caroline; Otto, Martin; Neumaier, Daniel

2017-01-01

In recent years, the data traffic has grown exponentially and the forecasts indicate a huge market that could be addressed by communication infrastructure and service providers. However, the processing capacity, space, and energy consumption of the available technology is a serious bottleneck for the exploitation of these markets. Chip-integrated optical communication systems hold the promise of significantly improving these issues related to the current technology. At the moment, the answer to the question which material is best suited for ultrafast chip integrated communication systems is still open. In this manuscript we report on ultrafast graphene photodetectors with a bandwidth of more than 76 GHz well suitable for communication links faster than 100 GBit s −1 per channel. We extract an upper value of 7.2 ps for the timescale in which the bolometric photoresponse in graphene is generated. The photodetectors were fabricated on 6″ silicon-on-insulator wafers in a semiconductor pilot line, demonstrating the scalable fabrication of high-performance graphene based devices. (paper)

Maximum Likelihood Time-of-Arrival Estimation of Optical Pulses via Photon-Counting Photodetectors

Science.gov (United States)

Erkmen, Baris I.; Moision, Bruce E.

2010-01-01

Many optical imaging, ranging, and communications systems rely on the estimation of the arrival time of an optical pulse. Recently, such systems have been increasingly employing photon-counting photodetector technology, which changes the statistics of the observed photocurrent. This requires time-of-arrival estimators to be developed and their performances characterized. The statistics of the output of an ideal photodetector, which are well modeled as a Poisson point process, were considered. An analytical model was developed for the mean-square error of the maximum likelihood (ML) estimator, demonstrating two phenomena that cause deviations from the minimum achievable error at low signal power. An approximation was derived to the threshold at which the ML estimator essentially fails to provide better than a random guess of the pulse arrival time. Comparing the analytic model performance predictions to those obtained via simulations, it was verified that the model accurately predicts the ML performance over all regimes considered. There is little prior art that attempts to understand the fundamental limitations to time-of-arrival estimation from Poisson statistics. This work establishes both a simple mathematical description of the error behavior, and the associated physical processes that yield this behavior. Previous work on mean-square error characterization for ML estimators has predominantly focused on additive Gaussian noise. This work demonstrates that the discrete nature of the Poisson noise process leads to a distinctly different error behavior.

Immunodetection of salivary biomarkers by an optical microfluidic biosensor with polyethylenimine-modified polythiophene-C70 organic photodetectors.

Science.gov (United States)

Dong, Tao; Pires, Nuno Miguel Matos

2017-08-15

This work reports a novel optical microfluidic biosensor with highly sensitive organic photodetectors (OPDs) for absorbance-based detection of salivary protein biomarkers at the point of care. The compact and miniaturized biosensor has comprised OPDs made of polythiophene-C 70 bulk heterojunction for the photoactive layer; whilst a calcium-free cathode interfacial layer, made of linear polyethylenimine, was incorporated to the photodetectors to enhance the low cost. The OPDs realized onto a glass chip were aligned to antibody-functionalized chambers of a poly(methyl methacrylate) microfluidic chip, in where immunogold-silver assays were conducted. The biosensor has detected IL-8, IL-1β and MMP-8 protein in spiked saliva with high detection specificity and short analysis time exhibiting detection limits between 80pgmL -1 and 120pgmL -1 . The result for IL-8 was below the clinical established cut-off of 600pgmL -1 , which revealed the potential of the biosensor to early detection of oral cancer. The detection limit was also comparable to other previously reported immunosensors performed with bulky instrumentation or using inorganic photodetectors. The optical detection sensitivity of the polythiophene-C 70 OPD was enhanced by optimizing the thickness of the photoactive layer and anode interfacial layer prior to the saliva immunoassays. Further, the biosensor was tested with unspiked human saliva samples, and the results of measuring IL-8 and IL-1β were in statistical agreement with those provided by two commercial assays of ELISA. The optical microfluidic biosensor reported hereby offers an attractive and cost-effective tool to diagnostics or screening purposes at the point of care. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimizing performance of silicon-based p-n junction photodetectors by the piezo-phototronic effect.

Science.gov (United States)

Wang, Zhaona; Yu, Ruomeng; Wen, Xiaonan; Liu, Ying; Pan, Caofeng; Wu, Wenzhuo; Wang, Zhong Lin

2014-12-23

Silicon-based p-n junction photodetectors (PDs) play an essential role in optoelectronic applications for photosensing due to their outstanding compatibility with well-developed integrated circuit technology. The piezo-phototronic effect, a three-way coupling effect among semiconductor properties, piezoelectric polarizations, and photon excitation, has been demonstrated as an effective approach to tune/modulate the generation, separation, and recombination of photogenerated electron-hole pairs during optoelectronic processes in piezoelectric-semiconductor materials. Here, we utilize the strain-induced piezo-polarization charges in a piezoelectric n-ZnO layer to modulate the optoelectronic process initiated in a p-Si layer and thus optimize the performances of p-Si/ZnO NWs hybridized photodetectors for visible sensing via tuning the transport property of charge carriers across the Si/ZnO heterojunction interface. The maximum photoresponsivity R of 7.1 A/W and fastest rising time of 101 ms were obtained from these PDs when applying an external compressive strain of -0.10‰ on the ZnO NWs, corresponding to relative enhancement of 177% in R and shortening to 87% in response time, respectively. These results indicate a promising method to enhance/optimize the performances of non-piezoelectric semiconductor material (e.g., Si) based optoelectronic devices by the piezo-phototronic effect.

Monolithic integration of SOI waveguide photodetectors and transimpedance amplifiers

Science.gov (United States)

Li, Shuxia; Tarr, N. Garry; Ye, Winnie N.

2018-02-01

In the absence of commercial foundry technologies offering silicon-on-insulator (SOI) photonics combined with Complementary Metal Oxide Semiconductor (CMOS) transistors, monolithic integration of conventional electronics with SOI photonics is difficult. Here we explore the implementation of lateral bipolar junction transistors (LBJTs) and Junction Field Effect Transistors (JFETs) in a commercial SOI photonics technology lacking MOS devices but offering a variety of n- and p-type ion implants intended to provide waveguide modulators and photodetectors. The fabrication makes use of the commercial Institute of Microelectronics (IME) SOI photonics technology. Based on knowledge of device doping and geometry, simple compact LBJT and JFET device models are developed. These models are then used to design basic transimpedance amplifiers integrated with optical waveguides. The devices' experimental current-voltage characteristics results are reported.

Two-Dimensional Halide Perovskites for Emerging New- Generation Photodetectors

DEFF Research Database (Denmark)

Tang, Yingying; Cao, Xianyi; Chi, Qijin

2018-01-01

Compared to their conventional three-dimensional (3D) counterparts, two-dimensional (2D) halide perovskites have attracted more interests recently in a variety of areas related to optoelectronics because of their unique structural characteristics and enhanced performances. In general, there are two...... distinct types of 2D halide perovskites. One represents those perovskites with an intrinsic layered crystal structure (i.e. MX6 layers, M = metal and X = Cl, Br, I), the other defines the perovskites with a 2D nanostructured morphology such as nanoplatelets and nanosheets. Recent studies have shown that 2D...... halide perovskites hold promising potential for the development of new-generation photodetectors, mainly arising from their highly efficient photoluminescence and absorbance, color tunability in the visible-light range and relatively high stability. In this chapter, we present the summary and highlights...

A cost-effective LED and photodetector based fast direct 3D diffuse optical imaging system

Science.gov (United States)

Saikia, Manob Jyoti; Manjappa, Rakesh; Kanhirodan, Rajan

2017-07-01

A cost-effective and high-speed 3D diffuse optical tomography system using high power LED light sources and silicon photodetectors has been designed and built, that can continuously scan and reconstruct spectroscopic images at a frame rate of 2 fps. The system is experimentally validated with tissue mimicking cylindrical resin phantom having light absorbing inhomogeneities of different size, shape and contrast, and at different locations.

Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

International Nuclear Information System (INIS)

Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H.; Kinge, Sachin

2015-01-01

Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO 2 layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10 −2  A W −1 and a shot-derived specific detectivity of 3 × 10 9  Jones at 1530 nm wavelength

Two-colour mid-infrared absorption in an InAs/GaSb-based type II and broken-gap quantum well

International Nuclear Information System (INIS)

Wei, X F; Xu, W; Zeng, Z

2007-01-01

We examine contributions from different transition channels to optical absorption in an InAs/GaSb-based type II and broken-gap quantum well (QW). In such a structure, because both electron and hole subbands are occupied by the conducting carriers, new channels open up for electronic transition via intra- and inter-layer scattering mechanisms. We find that two absorption peaks can be observed through inter-subband transitions within the same material layer. The absorption induced by the inter-layer transition is rather weak due to a small overlap of electron and hole wavefunctions. The results suggest that InAs/GaSb-based type II and broken-gap QWs can be employed as two-colour photodetectors working at mid-infrared bandwidth at relatively high temperatures up to room-temperature

Silicon photonics fiber-to-the-home transceiver array based on transfer-printing-based integration of III-V photodetectors.

Science.gov (United States)

Zhang, Jing; De Groote, Andreas; Abbasi, Amin; Loi, Ruggero; O'Callaghan, James; Corbett, Brian; Trindade, António José; Bower, Christopher A; Roelkens, Gunther

2017-06-26

A 4-channel silicon photonics transceiver array for Point-to-Point (P2P) fiber-to-the-home (FTTH) optical networks at the central office (CO) side is demonstrated. A III-V O-band photodetector array was integrated onto the silicon photonic transmitter through transfer printing technology, showing a polarization-independent responsivity of 0.39 - 0.49 A/W in the O-band. The integrated PDs (30 × 40 μm 2 mesa) have a 3 dB bandwidth of 11.5 GHz at -3 V bias. Together with high-speed C-band silicon ring modulators whose bandwidth is up to 15 GHz, operation of the transceiver array at 10 Gbit/s is demonstrated. The use of transfer printing for the integration of the III-V photodetectors allows for an efficient use of III-V material and enables the scalable integration of III-V devices on silicon photonics wafers, thereby reducing their cost.

Improved Photoresponse Performance of Self-Powered ZnO/Spiro-MeOTAD Heterojunction Ultraviolet Photodetector by Piezo-Phototronic Effect.

Science.gov (United States)

Shen, Yanwei; Yan, Xiaoqin; Si, Haonan; Lin, Pei; Liu, Yichong; Sun, Yihui; Zhang, Yue

2016-03-09

Strain-induced piezoelectric potential (piezopotential) within wurtzite-structured ZnO can engineer the energy-band structure at a contact or a junction and, thus, enhance the performance of corresponding optoelectronic devices by effectively tuning the charge carriers' separation and transport. Here, we report the fabrication of a flexible self-powered ZnO/Spiro-MeOTAD hybrid heterojunction ultraviolet photodetector (UV PD). The obtained device has a fast and stable response to the UV light illumination at zero bias. Together with responsivity and detectivity, the photocurrent can be increased about 1-fold upon applying a 0.753% tensile strain. The enhanced performance can be attributed to more efficient separation and transport of photogenerated electron-hole pairs, which is favored by the positive piezopotential modulated energy-band structure at the ZnO-Spiro-MeOTAD interface. This study demonstrates a promising approach to optimize the performance of a photodetector made of piezoelectric semiconductor materials through straining.

Thermal regulation of tightly packed solid-state photodetectors in a 1 mm{sup 3} resolution clinical PET system

Energy Technology Data Exchange (ETDEWEB)

Freese, D. L.; Vandenbroucke, A.; Innes, D.; Lau, F. W. Y.; Hsu, D. F. C.; Reynolds, P. D.; Levin, Craig S., E-mail: cslevin@stanford.edu [Departments of Electrical Engineering, Radiology, Physics, and BioEngineering, Stanford University, Stanford, California 94305-5128 (United States)

2015-01-15

Purpose: Silicon photodetectors are of significant interest for use in positron emission tomography (PET) systems due to their compact size, insensitivity to magnetic fields, and high quantum efficiency. However, one of their main disadvantages is fluctuations in temperature cause strong shifts in gain of the devices. PET system designs with high photodetector density suffer both increased thermal density and constrained options for thermally regulating the devices. This paper proposes a method of thermally regulating densely packed silicon photodetectors in the context of a 1 mm{sup 3} resolution, high-sensitivity PET camera dedicated to breast imaging. Methods: The PET camera under construction consists of 2304 units, each containing two 8 × 8 arrays of 1 mm{sup 3} LYSO crystals coupled to two position sensitive avalanche photodiodes (PSAPD). A subsection of the proposed camera with 512 PSAPDs has been constructed. The proposed thermal regulation design uses water-cooled heat sinks, thermoelectric elements, and thermistors to measure and regulate the temperature of the PSAPDs in a novel manner. Active cooling elements, placed at the edge of the detector stack due to limited access, are controlled based on collective leakage current and temperature measurements in order to keep all the PSAPDs at a consistent temperature. This thermal regulation design is characterized for the temperature profile across the camera and for the time required for cooling changes to propagate across the camera. These properties guide the implementation of a software-based, cascaded proportional-integral-derivative control loop that controls the current through the Peltier elements by monitoring thermistor temperature and leakage current. The stability of leakage current, temperature within the system using this control loop is tested over a period of 14 h. The energy resolution is then measured over a period of 8.66 h. Finally, the consistency of PSAPD gain between independent

Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting.

Science.gov (United States)

Kim, Soo Jin; Kang, Ju-Hyung; Mutlu, Mehmet; Park, Joonsuk; Park, Woosung; Goodson, Kenneth E; Sinclair, Robert; Fan, Shanhui; Kik, Pieter G; Brongersma, Mark L

2018-01-22

The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons.

Effects of structure and oxygen flow rate on the photo-response of amorphous IGZO-based photodetector devices

Science.gov (United States)

Jang, Jun Tae; Ko, Daehyun; Choi, Sungju; Kang, Hara; Kim, Jae-Young; Yu, Hye Ri; Ahn, Geumho; Jung, Haesun; Rhee, Jihyun; Lee, Heesung; Choi, Sung-Jin; Kim, Dong Myong; Kim, Dae Hwan

2018-02-01

In this study, we investigated how the structure and oxygen flow rate (OFR) during the sputter-deposition affects the photo-responses of amorphous indium-gallium-zinc-oxide (a-IGZO)-based photodetector devices. As the result of comparing three types of device structures with one another, which are a global Schottky diode, local Schottky diode, and thin-film transistor (TFT), the IGZO TFT with the gate pulse technique suppressing the persistent photoconductivity (PPC) is the most promising photodetector in terms of a high photo-sensitivity and uniform sensing characteristic. In order to analyze the IGZO TFT-based photodetectors more quantitatively, the time-evolution of sub-gap density-of-states (DOS) was directly observed under photo-illumination and consecutively during the PPC-compensating period with applying the gate pulse. It shows that the increased ionized oxygen vacancy (VO2+) defects under photo-illumination was fully recovered by the positive gate pulse and even overcompensated by additional electron trapping. Based on experimentally extracted sub-gap DOS, the origin on PPC was successfully decomposed into the hole trapping and the VO ionization. Although the VO ionization is enhanced in lower OFR (O-poor) device, the PPC becomes more severe in high OFR (O-rich) device because the hole trapping dominates the PPC in IGZO TFT under photo-illumination rather than the VO ionization and more abundant holes are trapped into gate insulator and/or interface in O-rich TFTs. Similarly, the electron trapping during the PPC-compensating period with applying the positive gate pulse becomes more prominent in O-rich TFTs. It is attributed to more hole/electron traps in the gate insulator and/or interface, which is associated with oxygen interstitials, or originates from the ion bombardment-related lower quality gate oxide in O-rich devices.

Long-wavelength III-V/silicon photonic integrated circuits

NARCIS (Netherlands)

Roelkens, G.C.; Kuyken, B.; Leo, F.; Hattasan, N.; Ryckeboer, E.M.P.; Muneeb, M.; Hu, C.L.; Malik, A.; Hens, Z.; Baets, R.G.F.; Shimura, Y.; Gencarelli, F.; Vincent, B.; Loo, van de R.; Verheyen, P.A.; Lepage, G.; Campenhout, van J.; Cerutti, L.; Rodriquez, J.B.; Tournie, E.; Chen, X; Nedeljkovic, G.; Mashanovich, G.; Liu, X.; Green, W.S.

2013-01-01

We review our work in the field of short-wave infrared and mid-infrared photonic integrated circuits for applications in spectroscopic sensing systems. Passive silicon waveguide circuits, GeSn photodetectors, the integration of III-V and IV-VI semiconductors on these circuits, and silicon nonlinear

High operating temperature interband cascade focal plane arrays

Energy Technology Data Exchange (ETDEWEB)

Tian, Z.-B.; Godoy, S. E.; Kim, H. S.; Schuler-Sandy, T.; Montoya, J. A.; Krishna, S. [Center for High Technology Materials, Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87106 (United States)

2014-08-04

In this paper, we report the initial demonstration of mid-infrared interband cascade (IC) photodetector focal plane arrays with multiple-stage/junction design. The merits of IC photodetectors include low noise and efficient photocarrier extraction, even for zero-bias operation. By adopting enhanced electron barrier design and a total absorber thickness of 0.7 μm, the 5-stage IC detectors show very low dark current (1.10 × 10{sup −7} A/cm{sup 2} at −5 mV and 150 K). Even with un-optimized fabrication and standard commercial (mis-matched) read-out circuit technology, infrared images are obtained by the 320 × 256 IC focal plane array up to 180 K with f/2.3 optics. The minimum noise equivalent temperature difference of 28 mK is obtained at 120 K. These initial results indicate great potential of IC photodetectors, particularly for high operating temperature applications.

High operating temperature interband cascade focal plane arrays

International Nuclear Information System (INIS)

Tian, Z.-B.; Godoy, S. E.; Kim, H. S.; Schuler-Sandy, T.; Montoya, J. A.; Krishna, S.

2014-01-01

In this paper, we report the initial demonstration of mid-infrared interband cascade (IC) photodetector focal plane arrays with multiple-stage/junction design. The merits of IC photodetectors include low noise and efficient photocarrier extraction, even for zero-bias operation. By adopting enhanced electron barrier design and a total absorber thickness of 0.7 μm, the 5-stage IC detectors show very low dark current (1.10 × 10 −7 A/cm 2 at −5 mV and 150 K). Even with un-optimized fabrication and standard commercial (mis-matched) read-out circuit technology, infrared images are obtained by the 320 × 256 IC focal plane array up to 180 K with f/2.3 optics. The minimum noise equivalent temperature difference of 28 mK is obtained at 120 K. These initial results indicate great potential of IC photodetectors, particularly for high operating temperature applications

Fabrication of cerium-doped β-Ga2O3 epitaxial thin films and deep ultraviolet photodetectors.

Science.gov (United States)

Li, Wenhao; Zhao, Xiaolong; Zhi, Yusong; Zhang, Xuhui; Chen, Zhengwei; Chu, Xulong; Yang, Hujiang; Wu, Zhenping; Tang, Weihua

2018-01-20

High-quality cerium-doped β-Ga 2 O 3 (Ga 2 O 3 :Ce) thin films could be achieved on (0001)α-Al 2 O 3 substrates using a pulsed-laser deposition method. The impact of dopant contents concentration on crystal structure, optical absorption, photoluminescence, and photoelectric properties has been intensively studied. X-ray diffraction analysis results have shown that Ga 2 O 3 :Ce films are highly (2¯01) oriented, and the lattice spacing of the (4¯02) planes is sensitive to the Ce doping level. The prepared Ga 2 O 3 :Ce films show a sharp absorption edge at about 250 nm, meaning a high transparency to deep ultraviolet (DUV) light. The photoluminescence results revealed that the emissions were in the violet-blue-green region, which are associated with the donor-acceptor transitions with the Ce 3+ and oxygen vacancies related defects. A simple DUV photodetector device with a metal-semiconductor-metal structure has also been fabricated based on Ga 2 O 3 :Ce thin film. A distinct DUV photoresponse was obtained, suggesting a potential application in DUV photodetector devices.

Single-layer graphene-TiO{sub 2} nanotubes array heterojunction for ultraviolet photodetector application

Energy Technology Data Exchange (ETDEWEB)

Zhang, Deng-Yue [School of Material Sciences and Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China); Ge, Cai-Wang [School of Electronic Science and Applied Physics, Hefei University of Technology, Hefei, Anhui 230009 (China); Wang, Jiu-Zhen [School of Material Sciences and Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China); Zhang, Teng-Fei [School of Electronic Science and Applied Physics, Hefei University of Technology, Hefei, Anhui 230009 (China); Wu, Yu-Cheng, E-mail: ycwu@hfut.edu.cn [School of Material Sciences and Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China); Liang, Feng-Xia, E-mail: fxliang@hfut.edu.cn [School of Material Sciences and Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China)

2016-11-30

Highlights: • Heterostructures comprised of a single-layer graphene and TiO{sub 2} nanotube arrays were constructed for ultraviolet detection. • The electrical properties of the fabricated heterostructures were dependent on the annealing atmospheres. • The effect of anodic TiO{sub 2} nanotube length on the performance of the photodetector were investigated. - Abstract: In this work, we reported on the fabrication of a single-layer graphene (SLG)-TiO{sub 2} nanotube arrays (NTs) heterostructures ultraviolet photodetector (UVPD) by transferring chemical vapor deposition derived MLG on the surface of anodic TiO{sub 2}NTs array. Through varying the annealing atmosphere and anodization time in the TiO{sub 2} synthesis procedure, the electronic and optoelectronic properties of the as-fabricated Schottky junction UVPD were studied. It was revealed that the anodic TiO{sub 2}NTs annealed in air showed a better rectifying behavior and was highly sensitive to UV light irradiation. Further investigation found that the device performance of the UVPD can be readily modulated by the anodization time, and the anodic TiO{sub 2}NTs with a medium tube length of 9.6 μm exhibits the highest device performance. These results demonstrated that the present SLG-TiO{sub 2}NTs array hetero-junction UVPD will be highly promising for fabricating high-performance optoelectronic device and system in the future.

Fabrications and application of single crystalline GaN for high-performance deep UV photodetectors

Energy Technology Data Exchange (ETDEWEB)

Velazquez, R.; Rivera, M.; Feng, P., E-mail: p.feng@upr.edu [Department of Physics, College of Natural Sciences, University of Puerto Rico, San Juan, 00936-8377, PR/USA (Puerto Rico); Aldalbahi, A. [Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)

2016-08-15

High-quality single crystalline Gallium Nitride (GaN) semiconductor has been synthesized using molecule beam epitaxy (MBE) technique for development of high-performance deep ultraviolet (UV) photodetectors. Thickness of the films was estimated by using surface profile meter and scanning electron microscope. Electronic states and elemental composition of the films were obtained using Raman scattering spectroscopy. The orientation, crystal structure and phase purity of the films were examined using a Siemens x-ray diffractometer radiation. The surface microstructure was studied using high resolution scanning electron microscopy (SEM). Two types of metal pairs: Al-Al, Al-Cu or Cu-Cu were used for interdigital electrodes on GaN film in order to examine the Schottky properties of the GaN based photodetector. The characterizations of the fabricated prototype include the stability, responsivity, response and recovery times. Typical time dependent photoresponsivity by switching different UV light source on and off five times for each 240 seconds at a bias of 2V, respectively, have been obtained. The detector appears to be highly sensitive to various UV wavelengths of light with very stable baseline and repeatability. The obtained photoresponsivity was up to 354 mA/W at the bias 2V. Higher photoresponsivity could be obtained if higher bias was applied but it would unavoidably result in a higher dark current. Thermal effect on the fabricated GaN based prototype was discussed.

Guided Growth of Horizontal ZnSe Nanowires and their Integration into High-Performance Blue-UV Photodetectors.

Science.gov (United States)

Oksenberg, Eitan; Popovitz-Biro, Ronit; Rechav, Katya; Joselevich, Ernesto

2015-07-15

Perfectly aligned horizontal ZnSe nano-wires are obtained by guided growth, and easily integrated into high-performance blue-UV photodetectors. Their crystal phase and crystallographic orientation are controlled by the epitaxial relations with six different sapphire planes. Guided growth paves the way for the large-scale integration of nanowires into optoelectronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solution processed Cu2SnS3 thin films for visible and infrared photodetector applications

Directory of Open Access Journals (Sweden)

Sandra Dias

2016-02-01

Full Text Available The Cu2SnS3 thin films were deposited using an economic, solution processible, spin coating technique. The films were found to possess a tetragonal crystal structure using X-ray diffraction. The film morphology and the particle size were determined using scanning electron microscopy. The various planes in the crystal were observed using transmission electron microscopy. The optimum band gap of 1.23 eV and a high absorption coefficient of 104 cm−1 corroborate its application as a photoactive material. The visible and infrared (IR photo response was studied for various illumination intensities. The current increased by one order from a dark current of 0.31 μA to a current of 1.78 μA at 1.05 suns and 8.7 μA under 477.7 mW/cm2 IR illumination intensity, at 3 V applied bias. The responsivity, sensitivity, external quantum efficiency and specific detectivity were found to be 10.93 mA/W, 5.74, 2.47% and 3.47 × 1010 Jones respectively at 1.05 suns and 16.32 mA/W, 27.16, 2.53% and 5.10 × 1010 Jones respectively at 477.7 mW/cm2 IR illumination. The transient photoresponse was measured both for visible and IR illuminations.

Study of SiPM as a potential photodetector for scintillator readout

International Nuclear Information System (INIS)

Herbert, D.J.; D'Ascenzo, N.; Belcari, N.; Del Guerra, A.; Morsani, F.; Saveliev, V.

2006-01-01

The Silicon PhotoMultiplier (SiPM) APD represents an interesting advance in photodetection and could soon be a rival to traditional PMTs in many applications. The SiPM is effectively a densely packed 2D array of Geiger-mode APD microcells, each having individual resistive quenching and multiplexed outputs. In this way the SiPM acts as a linear, high-gain photodetector for moderate photon flux (N photon cells ). The Metal-Resistor-Silicon (MRS) structure SiPM, produced by CPTA Russia, has been characterised and tested for scintillator light detection in medical applications such as PET. We present a summary of measurements of the device's primary operating characteristics and results of the application to scintillator readout

Piezo-phototronic effect enhanced UV photodetector based on CuI/ZnO double-shell grown on flexible copper microwire.

Science.gov (United States)

Liu, Jingyu; Zhang, Yang; Liu, Caihong; Peng, Mingzeng; Yu, Aifang; Kou, Jinzong; Liu, Wei; Zhai, Junyi; Liu, Juan

2016-12-01

In this work, we present a facile, low-cost, and effective approach to fabricate the UV photodetector with a CuI/ZnO double-shell nanostructure which was grown on common copper microwire. The enhanced performances of Cu/CuI/ZnO core/double-shell microwire photodetector resulted from the formation of heterojunction. Benefiting from the piezo-phototronic effect, the presentation of piezocharges can lower the barrier height and facilitate the charge transport across heterojunction. The photosensing abilities of the Cu/CuI/ZnO core/double-shell microwire detector are investigated under different UV light densities and strain conditions. We demonstrate the I-V characteristic of the as-prepared core/double-shell device; it is quite sensitive to applied strain, which indicates that the piezo-phototronic effect plays an essential role in facilitating charge carrier transport across the CuI/ZnO heterojunction, then the performance of the device is further boosted under external strain.

The new oxide paradigm for solid state ultraviolet photodetectors

Science.gov (United States)

Rogers, D. J.; Bove, P.; Arrateig, X.; Sandana, V. E.; Teherani, F. H.; Razeghi, M.; McClintock, R.; Frisch, E.; Harel, S.

2018-03-01

The bandgap of wurzite ZnO layers grown on 2 inch diameter c-Al2O3 substrates by pulsed laser deposition was engineered from 3.7 to 4.8 eV by alloying with Mg. Above this Mg content the layers transformed from single phase hcp to mixed hcp/fcc phase before becoming single phase fcc above a bandgap of about 5.5 eV. Metal-Semiconductor-Metal (MSM) photodetectors based on gold Inter-Digitated-Transducer structures were fabricated from the single phase hcp layers by single step negative photolithography and then packaged in TO5 cans. The devices gave over 6 orders of magnitude of separation between dark and light signal with solar rejection ratios (I270 : I350) of over 3 × 105 and dark signals of 300 pA (at a bias of -5V). Spectral responsivities were engineered to fit the "Deutscher Verein des Gas- und Wasserfaches" industry standard form and gave over two decade higher responsivities (14 A/W, peaked at 270 nm) than commercial SiC based devices. Homogeneous Ga2O3 layers were also grown on 2 inch diameter c-Al2O3 substrates by PLD. Optical transmission spectra were coherent with a bandgap that increased from 4.9 to 5.4 eV when film thickness was decreased from 825 to 145 nm. X-ray diffraction revealed that the films were of the β-Ga2O3 (monoclinic) polytype with strong (-201) orientation. β-Ga2O3 MSM photodetectors gave over 4 orders of magnitude of separation between dark and light signal (at -5V bias) with dark currents of 250 pA and spectral responsivities of up to 40 A/W (at -0.75V bias). It was found that the spectral responsivity peak position could be decreased from 250 to 230 nm by reducing film thickness from 825 to 145 nm. This shift in peak responsivity wavelength with film thickness (a) was coherent with the apparent bandgap shift that was observed in transmission spectroscopy for the same layers and (b) conveniently provides a coverage of the spectral region in which MgZnO layers show fcc/hcp phase mixing.

Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

Energy Technology Data Exchange (ETDEWEB)

Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H., E-mail: ted.sargent@utoronto.ca [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Kinge, Sachin [Advanced Technology, Materials and Research, Research and Development, Hoge Wei 33- Toyota Technical Centre, B-1930 Zaventem (Belgium)

2015-10-12

Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

Progress on the development of a silicon–carbon nanotube photodetector

Energy Technology Data Exchange (ETDEWEB)

Aramo, C., E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, A. [CNR-SPIN, U.O.S. di Napoli (Italy); Dipartimento di Scienze Fisiche, Universitá degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Battiston, R. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universitá degli Studi di Perugia, Piazza Universitá 1, 06100 Perugia (Italy); Castrucci, P. [Dipartimento di Fisica, Universitá degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Cilmo, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); De Crescenzi, M. [Dipartimento di Fisica, Universitá degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Fiandrini, E. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universitá degli Studi di Perugia, Piazza Universitá 1, 06100 Perugia (Italy); Guarino, F. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Universitá degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Grossi, V. [Dipartimento di Fisica, Universitá degli Studi dell Aquila, Via Vetoio 10, 67100 Coppito, LAquila (Italy); Maddalena, P. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Universitá degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Nappi, E. [INFN, Sezione di Bari e Dipartimento di Fisica, Universitá degli Studi di Bari, Via Amendola 173, 70126 Bari (Italy); and others

2013-08-01

The properties of carbon nanotubes (CNTs), the new allotropic status of carbon discovered in 1991, have been widely investigated in all possible application field. This new material in fact can be easily obtained chemically by CVD (Chemical Vapour Deposition) as a layer of nanotubes growth on a wide variety of materials. When growth on a silicon surface, CNTs create a semiconductor heterojunction with peculiar photoresponsivity properties. We studied this heterojunction with the purpose to realize a large photocathode with high quantum efficiency in a large wavelength range from UV to IR. Results obtained up to day allowed us to build a new kind of photodetector very cheap, stable and easy to manage. Recently this new device has been proposed as one of candidates for the beam monitor system of SuperB.

Monolithic optoelectronic integrated broadband optical receiver with graphene photodetectors

Directory of Open Access Journals (Sweden)

Cheng Chuantong

2017-07-01

Full Text Available Optical receivers with potentially high operation bandwidth and low cost have received considerable interest due to rapidly growing data traffic and potential Tb/s optical interconnect requirements. Experimental realization of 65 GHz optical signal detection and 262 GHz intrinsic operation speed reveals the significance role of graphene photodetectors (PDs in optical interconnect domains. In this work, a novel complementary metal oxide semiconductor post-backend process has been developed for integrating graphene PDs onto silicon integrated circuit chips. A prototype monolithic optoelectronic integrated optical receiver has been successfully demonstrated for the first time. Moreover, this is a firstly reported broadband optical receiver benefiting from natural broadband light absorption features of graphene material. This work is a perfect exhibition of the concept of monolithic optoelectronic integration and will pave way to monolithically integrated graphene optoelectronic devices with silicon ICs for three-dimensional optoelectronic integrated circuit chips.

Monolithic optoelectronic integrated broadband optical receiver with graphene photodetectors

Science.gov (United States)

Cheng, Chuantong; Huang, Beiju; Mao, Xurui; Zhang, Zanyun; Zhang, Zan; Geng, Zhaoxin; Xue, Ping; Chen, Hongda

2017-07-01

Optical receivers with potentially high operation bandwidth and low cost have received considerable interest due to rapidly growing data traffic and potential Tb/s optical interconnect requirements. Experimental realization of 65 GHz optical signal detection and 262 GHz intrinsic operation speed reveals the significance role of graphene photodetectors (PDs) in optical interconnect domains. In this work, a novel complementary metal oxide semiconductor post-backend process has been developed for integrating graphene PDs onto silicon integrated circuit chips. A prototype monolithic optoelectronic integrated optical receiver has been successfully demonstrated for the first time. Moreover, this is a firstly reported broadband optical receiver benefiting from natural broadband light absorption features of graphene material. This work is a perfect exhibition of the concept of monolithic optoelectronic integration and will pave way to monolithically integrated graphene optoelectronic devices with silicon ICs for three-dimensional optoelectronic integrated circuit chips.

Sub-Band Gap Turn-On Near-Infrared-to-Visible Up-Conversion Device Enabled by an Organic-Inorganic Hybrid Perovskite Photovoltaic Absorber.

Science.gov (United States)

Yu, By Hyeonggeun; Cheng, Yuanhang; Li, Menglin; Tsang, Sai-Wing; So, Franky

2018-05-09

Direct integration of an infrared (IR) photodetector with an organic light-emitting diode (OLED) enables low-cost, pixel-free IR imaging. However, the operation voltage of the resulting IR-to-visible up-conversion is large because of the series device architecture. Here, we report a low-voltage near-IR (NIR)-to-visible up-conversion device using formamidinium lead iodide as a NIR absorber integrated with a phosphorescent OLED. Because of the efficient photocarrier injection from the hybrid perovskite layer to the OLED, we observed a sub-band gap turn-on of the OLED under NIR illumination. The device showed a NIR-to-visible up-conversion efficiency of 3% and a luminance on/off ratio of 10 3 at only 5 V. Finally, we demonstrate pixel-free NIR imaging using the up-conversion device.

Silicon-based visible and near-infrared optoelectric devices

Energy Technology Data Exchange (ETDEWEB)

Mazur, Eric; Carey, James Edward

2017-10-17

In one aspect, the present invention provides a silicon photodetector having a surface layer that is doped with sulfur inclusions with an average concentration in a range of about 0.5 atom percent to about 1.5 atom percent. The surface layer forms a diode junction with an underlying portion of the substrate. A plurality of electrical contacts allow application of a reverse bias voltage to the junction in order to facilitate generation of an electrical signal, e.g., a photocurrent, in response to irradiation of the surface layer. The photodetector exhibits a responsivity greater than about 1 A/W for incident wavelengths in a range of about 250 nm to about 1050 nm, and a responsivity greater than about 0.1 A/W for longer wavelengths, e.g., up to about 3.5 microns.

2D Organic-Inorganic Hybrid Thin Films for Flexible UV-Visible Photodetectors

KAUST Repository

Velusamy, Dhinesh Babu

2017-02-13

Flexible 2D inorganic MoS and organic g-CN hybrid thin film photodetectors with tunable composition and photodetection properties are developed using simple solution processing. The hybrid films fabricated on paper substrate show broadband photodetection suitable for both UV and visible light with good responsivity, detectivity, and reliable and rapid photoswitching characteristics comparable to monolayer devices. This excellent performance is retained even after the films are severely deformed at a bending radius of ≈2 mm for hundreds of cycles. The detailed charge transfer and separation processes at the interface between the 2D materials in the hybrid films are confirmed by femtosecond transient absorption spectroscopy with broadband capability.

On the vulnerability of basic quantum key distribution protocols and three protocols stable to attack with 'blinding' of avalanche photodetectors

Energy Technology Data Exchange (ETDEWEB)

Molotkov, S. N., E-mail: sergei.molotkov@gmail.com [Russian Federation Academy of Cryptography (Russian Federation)

2012-05-15

The fundamental quantum mechanics prohibitions on the measurability of quantum states allow secure key distribution between spatially remote users to be performed. Experimental and commercial implementations of quantum cryptography systems, however, use components that exist at the current technology level, in particular, one-photon avalanche photodetectors. These detectors are subject to the blinding effect. It was shown that all the known basic quantum key distribution protocols and systems based on them are vulnerable to attacks with blinding of photodetectors. In such attacks, an eavesdropper knows all the key transferred, does not produce errors at the reception side, and remains undetected. Three protocols of quantum key distribution stable toward such attacks are suggested. The security of keys and detection of eavesdropping attempts are guaranteed by the internal structure of protocols themselves rather than additional technical improvements.

Defect-based graphene nanoribbon photodetectors: A numerical study

Energy Technology Data Exchange (ETDEWEB)

Zarei, M. H.; Sharifi, M. J., E-mail: m-j-sharifi@sbu.ac.ir [Department of Electrical Engineering, Shahid Beheshti University, Tehran 1983963113 (Iran, Islamic Republic of)

2016-06-07

Recently, some photodetectors based on graphene have been proposed. In all of these works, current generation was carried out by separation of photo-excited carriers using an electric field, either internal or external. In this work, a new method of producing current which is based on different transmission coefficients for electrons and holes when they travel toward any of the two contacts is proposed. To this end, a single Stone–Wales defect close to one of the two contacts was used to break the channel symmetry. In order to confirm the idea, the non-equilibrium Green's function formalism in real space in conjunction with the tight binding method was used in simulations. In addition, to clarify the results, we present a classical model in which different diffusion constants are assumed for the left going and the right going carriers. Additional simulations for different positions of the defect, different lengths of the ribbon, and different bias voltages were performed, and the results are included in this study.

Fine--Mesh Photodetectors for CMS Endcap Electromagnetic Calorimeter

CERN Document Server

Bajanov, N A; Golubev, Nikolai; Gusev, Yuri; Kachanov, Vassili; Klechneva, T Y; Kovalev, A I; Levtchenko, L A; Lukyanov, Valery; Mamaeva, Galina; Moroz, Feodor; Prilutskaya, D M; Seliverstov, Dmitry; Blinnikov, Yuri

1998-01-01

The behaviour of fine-mesh vacuum phototetrodes and phototriodes ( VPTs) in an axial magnetic field of ( 0 -- 4)T has been investigated. The measured VPT parameters are: fine-mesh cell dimensions, the photocathode sensitivity and its homogenity, the gain in zero and 4T magnetic field at tilt angles corresponding to the rapidity range of CMS ECAL Endcap 1.479 -- 3.0 and excess noise factor. Measurements have been performed on 21 and 30 mm diameter photodetectors with different fine-mesh structures: 30, 60 and 100 lines per mm under different types of photocathode illumination by green LED. Phototriodes with 30 or 60 lines per mm and an external diameter of 21 mm are found to be the best candidates for the CMS environment with the initial size of PWO crystals proposed to be used in the Endcap, by comparison with phototetrodes. They provide a gain of the order of 6 -- 8 in 4T magnetic field and an excess noise factor of 2 under full photocathode illumination.

Electrostatics and quantum efficiency simulations of asymmetrically contacted carbon nanotube photodetector

Directory of Open Access Journals (Sweden)

Xiao Guo

2017-10-01

Full Text Available Electrostatic properties of asymmetrically contacted carbon nanotube barrier-free bipolar diode photodetector are studied by solving the Poisson equation self-consistently with equilibrium carrier statistics. For electric field parallel to tube’s axis, the maximum electric field occurs near contact but decays rapidly in a few nanometers, followed by a slowly increasing trend when it extends to the center of channel. By considering the field ionization and the diffusion effect of exciton, a model of estimation on quantum efficiency for the device is made. We find that the quantum efficiency increases with increasing exciton lifetime, decreasing diffusion constant and channel length. For devices with a channel length shorter than 50 nm, the contribution of field ionization to the quantum efficiency can reach 60%.

Silver nanowires-templated metal oxide for broadband Schottky photodetector

Energy Technology Data Exchange (ETDEWEB)

Patel, Malkeshkumar; Kim, Hong-Sik; Kim, Joondong, E-mail: joonkim@inu.ac.kr [Photoelectric and Energy Device Application Lab (PEDAL) and Department of Electrical Engineering, Incheon National University, 119 Academy Rd. Yeonsu, Incheon 406772 (Korea, Republic of); Park, Hyeong-Ho [Applied Device and Material Lab., Device Technology Division, Korea Advanced Nano Fab Center (KANC), Suwon 443270 (Korea, Republic of)

2016-04-04

Silver nanowires (AgNWs)-templated transparent metal oxide layer was applied for Si Schottky junction device, which remarked the record fastest photoresponse of 3.4 μs. Self-operating AgNWs-templated Schottky photodetector showed broad wavelength photodetection with high responsivity (42.4 A W{sup −1}) and detectivity (2.75 × 10{sup 15} Jones). AgNWs-templated indium-tin-oxide (ITO) showed band-to-band excitation due to the internal photoemission, resulting in significant carrier collection performances. Functional metal oxide layer was formed by AgNWs-templated from ITO structure. The grown ITO above AgNWs has a cylindrical shape and acts as a thermal protector of AgNWs for high temperature environment without any deformation. We developed thermal stable AgNWs-templated transparent oxide devices and demonstrated the working mechanism of AgNWs-templated Schottky devices. We may propose the high potential of hybrid transparent layer design for various photoelectric applications, including solar cells.

SNR characteristics of 850-nm OEIC receiver with a silicon avalanche photodetector.

Science.gov (United States)

Youn, Jin-Sung; Lee, Myung-Jae; Park, Kang-Yeob; Rücker, Holger; Choi, Woo-Young

2014-01-13

We investigate signal-to-noise ratio (SNR) characteristics of an 850-nm optoelectronic integrated circuit (OEIC) receiver fabricated with standard 0.25-µm SiGe bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The OEIC receiver is composed of a Si avalanche photodetector (APD) and BiCMOS analog circuits including a transimpedance amplifier with DC-balanced buffer, a tunable equalizer, a limiting amplifier, and an output buffer with 50-Ω loads. We measure APD SNR characteristics dependence on the reverse bias voltage as well as BiCMOS circuit noise characteristics. From these, we determine the SNR characteristics of the entire OEIC receiver, and finally, the results are verified with bit-error rate measurement.

Multicolor (UV-IR) Photodetectors Based on Lattice-Matched 6.1 A II/VI and III/V Semiconductors

Science.gov (United States)

2015-08-27

copyright information. 13. SUPPLEMENTARY NOTES. Enter information not included elsewhere such as: prepared in cooperation with; translation of; report...II-VI heterojunctions such as multi-color photodetectors and solar cells [2]. Mixing lattice-matched II-VI and III-V semiconductors could be an...at 77 K, further silicon oxide surface passivation can be done to suppress the surface leakage [10] in the future work. Figure 10 The dark I-V

Hybrid photodetector based on CsPbBr3 perovskite nanocrystals and PC71BM fullerene derivative

Science.gov (United States)

Li, Tengteng; Liu, Meihong; Li, Qingyan; Chen, Run; Liu, Xin

2018-05-01

Here, a hybrid perovskite-organic photodetector was fabricated by integrating CsPbBr3 nanocrystals (NCs) with [6,6]-phenyl C71 butyric acid methyl ester (PC71BM), exhibiting remarkable optoelectronic properties in terms of photoresponsivity (1.72 A/W), detectivity (1.76 × 107 Jones), external quantum efficiency (EQE) (530%) under the illumination of 405 nm laser, and photoresponse time is shorter than 0.1 ms due to the assistance of heterojunction on the separation of photoexcitons.

Effect of the nanowire diameter on the linearity of the response of GaN-based heterostructured nanowire photodetectors

Science.gov (United States)

Spies, Maria; Polaczyński, Jakub; Ajay, Akhil; Kalita, Dipankar; Luong, Minh Anh; Lähnemann, Jonas; Gayral, Bruno; den Hertog, Martien I.; Monroy, Eva

2018-06-01

Nanowire photodetectors are investigated because of their compatibility with flexible electronics, or for the implementation of on-chip optical interconnects. Such devices are characterized by ultrahigh photocurrent gain, but their photoresponse scales sublinearly with the optical power. Here, we present a study of single-nanowire photodetectors displaying a linear response to ultraviolet illumination. Their structure consists of a GaN nanowire incorporating an AlN/GaN/AlN heterostructure, which generates an internal electric field. The activity of the heterostructure is confirmed by the rectifying behavior of the current–voltage characteristics in the dark, as well as by the asymmetry of the photoresponse in magnitude and linearity. Under reverse bias (negative bias on the GaN cap segment), the detectors behave linearly with the impinging optical power when the nanowire diameter is below a certain threshold (≈80 nm), which corresponds to the total depletion of the nanowire stem due to the Fermi level pinning at the sidewalls. In the case of nanowires that are only partially depleted, their nonlinearity is explained by a nonlinear variation of the diameter of their central conducting channel under illumination.

Postannealing Effect at Various Gas Ambients on Ohmic Contacts of Pt/ZnO Nanobilayers toward Ultraviolet Photodetectors

Directory of Open Access Journals (Sweden)

Chung-Hua Chao

2013-01-01

Full Text Available This paper describes a fabrication and characterization of ultraviolet (UV photodetectors based on Ohmic contacts using Pt electrode onto the epitaxial ZnO (0002 thin film. Plasma enhanced chemical vapor deposition (PECVD system was employed to deposit ZnO (0002 thin films onto silicon substrates, and radio-frequency (RF magnetron sputtering was used to deposit Pt top electrode onto the ZnO thin films. The as-deposited Pt/ZnO nanobilayer samples were then annealed at 450∘C in two different ambients (argon and nitrogen to obtain optimal Ohmic contacts. The crystal structure, surface morphology, optical properties, and wettability of ZnO thin films were analyzed by X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, atomic force microscopy (AFM, photoluminescence (PL, UV-Vis-NIR spectrophotometer, and contact angle meter, respectively. Moreover, the photoconductivity of the Pt/ZnO nanobilayers was also investigated for UV photodetector application. The above results showed that the optimum ZnO sample was synthesized with gas flow rate ratio of 1 : 3 diethylzinc [DEZn, Zn(C2H52] to carbon dioxide (CO2 and then combined with Pt electrode annealed at 450∘C in argon ambient, exhibiting good crystallinity as well as UV photo responsibility.

Visible-Blind UV Photodetector Based on Single-Walled Carbon Nanotube Thin Film/ZnO Vertical Heterostructures.

Science.gov (United States)

Li, Guanghui; Suja, Mohammad; Chen, Mingguang; Bekyarova, Elena; Haddon, Robert C; Liu, Jianlin; Itkis, Mikhail E

2017-10-25

Ultraviolet (UV) photodetectors based on heterojunctions of conventional (Ge, Si, and GaAs) and wide bandgap semiconductors have been recently demonstrated, but achieving high UV sensitivity and visible-blind photodetection still remains a challenge. Here, we utilized a semitransparent film of p-type semiconducting single-walled carbon nanotubes (SC-SWNTs) with an energy gap of 0.68 ± 0.07 eV in combination with a molecular beam epitaxy grown n-ZnO layer to build a vertical p-SC-SWNT/n-ZnO heterojunction-based UV photodetector. The resulting device shows a current rectification ratio of 10 3 , a current photoresponsivity up to 400 A/W in the UV spectral range from 370 to 230 nm, and a low dark current. The detector is practically visible-blind with the UV-to-visible photoresponsivity ratio of 10 5 due to extremely short photocarrier lifetimes in the one-dimensional SWNTs because of strong electron-phonon interactions leading to exciton formation. In this vertical configuration, UV radiation penetrates the top semitransparent SC-SWNT layer with low losses (10-20%) and excites photocarriers within the n-ZnO layer in close proximity to the p-SC-SWNT/n-ZnO interface, where electron-hole pairs are efficiently separated by a high built-in electric field associated with the heterojunction.

THE IMPACT OF EVOLVING INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF GALAXIES ON STAR FORMATION RATE ESTIMATES

Energy Technology Data Exchange (ETDEWEB)

Nordon, R.; Lutz, D.; Genzel, R.; Berta, S.; Wuyts, S.; Magnelli, B.; Foerster Schreiber, N. M.; Poglitsch, A.; Popesso, P. [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany); Altieri, B. [Herschel Science Centre, European Space Astronomy Centre, ESA, Villanueva de al Canada, 28691 Madrid (Spain); Andreani, P. [ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Aussel, H.; Daddi, E. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d' Astrophysique, Bat.709, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France); Bongiovanni, A.; Cepa, J.; Perez Garcia, A. M. [Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife (Spain); Cimatti, A. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy); Fadda, D. [IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Lagache, G. [Institut d' Astrophysique Spatiale (IAS), Bat 121, Universite de Paris XI, 91450 Orsay Cedex (France); Maiolino, R., E-mail: nordon@mpe.mpg.de [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone (Italy); and others

2012-02-01

We combine Herschel-Photodetector Array Camera and Spectrometer (PACS) data from the PACS Evolutionary Probe (PEP) program with Spitzer 24 {mu}m and 16 {mu}m photometry and ultra deep Infrared Spectrograph (IRS) mid-infrared spectra to measure the mid- to far-infrared spectral energy distribution (SED) of 0.7 < z < 2.5 normal star-forming galaxies (SFGs) around the main sequence (the redshift-dependent relation of star formation rate (SFR) and stellar mass). Our very deep data confirm from individual far-infrared detections that z {approx} 2 SFRs are overestimated if based on 24 {mu}m fluxes and SED templates that are calibrated via local trends with luminosity. Galaxies with similar ratios of rest-frame {nu}L{sub {nu}}(8) to 8-1000 {mu}m infrared luminosity (LIR) tend to lie along lines of constant offset from the main sequence. We explore the relation between SED shape and offset in specific star formation rate (SSFR) from the redshift-dependent main sequence. Main-sequence galaxies tend to have a similar {nu}L{sub {nu}}(8)/LIR regardless of LIR and redshift, up to z {approx} 2.5, and {nu}L{sub {nu}}(8)/LIR decreases with increasing offset above the main sequence in a consistent way at the studied redshifts. We provide a redshift-independent calibration of SED templates in the range of 8-60 {mu}m as a function of {Delta}log(SSFR) offset from the main sequence. Redshift dependency enters only through the evolution of the main sequence with time. Ultra deep IRS spectra match these SED trends well and verify that they are mostly due to a change in ratio of polycyclic aromatic hydrocarbon (PAH) to LIR rather than continua of hidden active galactic nuclei (AGNs). Alternatively, we discuss the dependence of {nu}L{sub {nu}}(8)/LIR on LIR. The same {nu}L{sub {nu}}(8)/LIR is reached at increasingly higher LIR at higher redshift, with shifts relative to local by 0.5 and 0.8 dex in log(LIR) at redshifts z {approx} 1 and z {approx} 2. Corresponding SED template calibrations

Development of a 13-in. Hybrid Avalanche Photo-Detector (HAPD) for a next generation water Cherenkov detector

International Nuclear Information System (INIS)

Nakayama, H.; Kusaka, A.; Kakuno, H.; Abe, T.; Iwasaki, M.; Aihara, H.; Shiozawa, M.; Tanaka, M.; Kyushima, H.; Suyama, M.; Kawai, Y.

2006-01-01

We have developed a 13-in. Hybrid Avalanche Photo-Detector (HAPD) for photosensors in next generation water Cherenkov type detectors. We study the performance of the HAPD and the results show good time resolution better than σ=1ns, good sensitivity for single photon detection, wide dynamic range, and good uniformity on the photocathode. The HAPD is also expected to be less expensive than large PMTs because of its simpler structure without dynodes

Multiple resonant absorber with prism-incorporated graphene and one-dimensional photonic crystals in the visible and near-infrared spectral range

Science.gov (United States)

Zou, X. J.; Zheng, G. G.; Chen, Y. Y.; Xu, L. H.; Lai, M.

2018-04-01

A multi-band absorber constructed from prism-incorporated one-dimensional photonic crystal (1D-PhC) containing graphene defects is achieved theoretically in the visible and near-infrared (vis-NIR) spectral range. By means of the transfer matrix method (TMM), the effect of structural parameters on the optical response of the structure has been investigated. It is possible to achieve multi-peak and complete optical absorption. The simulations reveal that the light intensity is enhanced at the graphene plane, and the resonant wavelength and the absorption intensity can also be tuned by tilting the incidence angle of the impinging light. In particular, multiple graphene sheets are embedded in the arrays, without any demand of manufacture process to cut them into periodic patterns. The proposed concept can be extended to other two-dimensional (2D) materials and engineered for promising applications, including selective or multiplex filters, multiple channel sensors, and photodetectors.

Fabrication of a novel gigabit/second free-space optical interconnect - photodetector characterization and testing and system development

Science.gov (United States)

Savich, Gregory R.

2004-01-01

The time when computing power is limited by the copper wire inherent in the computer system and not the speed of the microprocessor is rapidly approaching. With constant advances in computer technology, many researchers believe that in only a few years, optical interconnects will begin to replace copper wires in your Central Processing Unit (CPU). On a more macroscopic scale, the telecommunications industry has already made the switch to optical data transmission as, to date, fiber optic technology is the only reasonable method of reliable, long range data transmission. Within the span of a decade, we will see optical technologies move from the macroscopic world of the telecommunications industry to the microscopic world of the computer chip. Already, the communications industry is marketing commercially available optical links to connect two personal computers, thereby eliminating the need for standard and comparatively slow wired and wireless Ethernet transfers and greatly increasing the distance the computers can be separated. As processing demands continue to increase, the realm of optical communications will continue to move closer to the microprocessor and quite possibly onto the microprocessor itself. A day may come when copper connections are used only to supply power, not transfer data. This summer s work marks some of the beginning stages of a 5 to 10 year, long-term research project to create and study a free-space, 1 Gigabit/sec optical interconnect. The research will result in a novel fabricated, chip-to-chip interconnect consisting of a Vertical Cavity Surface Emitting Laser (VCSEL) Diode linked through free space to a Metal- Semiconductor-Metal (MSM) Photodetector with the possible integration of microlenses for signal focusing and Micro-Electromechanical Systems (MEMS) devices for optical signal steering. The advantages, disadvantages, and practicality of incorporating flip-chip mounting technologies will also be addressed. My work began with the

Far infrared supplement: Catalog of infrared observations, second edition

International Nuclear Information System (INIS)

Gezari, D.Y.; Schmitz, M.; Mead, J.M.

1988-08-01

The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed

Structural and optical properties of germanium nanostructures on Si(100 and embedded in high-k oxides

Directory of Open Access Journals (Sweden)

Ray Samit

2011-01-01

Full Text Available Abstract The structural and optical properties of Ge quantum dots (QDs grown on Si(001 for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented. The infrared photoluminescence (PL signal from Ge islands has been studied at a low temperature. The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001 QDs infrared photodetector device are presented. The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied. Transmission electron micrographs have revealed the formation of isolated spherical Ge nanocrystals in high-k oxide matrix of sizes ranging from 4 to 18 nm. Embedded nanocrystals in high band gap oxides have been found to act as discrete trapping sites for exchanging charge carriers with the conduction channel by direct tunneling that is desired for applications in floating gate memory devices.

Development of TiBr semiconductor crystal for applications as radiation detector and photodetector

International Nuclear Information System (INIS)

Oliveira, Icimone Braga de

2006-01-01

In this work, Tlbr crystals were grown by the Bridgman method from zone melted materials. The influence of the purification efficiency and the crystalline surface quality on the crystal were studied, evaluating its performance as a radiation detector. Due to significant improvement in the purification and crystals growth, good results have been obtained for the developed detectors. The spectrometric performance of the Tlbr detector was evaluated by 241 Am (59 keV), 133 Ba (80 e 355 keV), 57 Co (122 keV), 22 Na (511 keV) and 137 Cs (662 keV) at room temperature. The best energy resolution results were obtained from purer detectors. Energy resolutions of 10 keV (16%), 12 keV (15%), 12 keV (10%), 28 keV (8%), 31 keV (6%) and 36 keV (5%) to 59, 80, 122, 355, 511 and 662 keV energies, respectively, were obtained. A study on the detection response at -20 deg C was also carried out, as well as the detector stability in function of the time. No significant difference was observed in the energy resolution between measurements at both temperatures. It was observed that the detector instability causes degradation of the spectroscopic characteristics during measurements at room temperature and the instability varies for each detector. This behavior was also verified by other authors. The viability to use the developed Tlbr crystal as a photodetector coupled to scintillators crystals was also studied in this work. Due to its quantum efficiency in the region from 350 to 500 nm, Tlbr shows to be a promising material to be used as a photodetector. As a possible application of this work, the development of a surgical probe has been initiated using the developed Tlbr crystal as the radiation detector of the probe. (author)

64 x 64 thresholding photodetector array for optical pattern recognition

Science.gov (United States)

Langenbacher, Harry; Chao, Tien-Hsin; Shaw, Timothy; Yu, Jeffrey W.

1993-10-01

A high performance 32 X 32 peak detector array is introduced. This detector consists of a 32 X 32 array of thresholding photo-transistor cells, manufactured with a standard MOSIS digital 2-micron CMOS process. A built-in thresholding function that is able to perform 1024 thresholding operations in parallel strongly distinguishes this chip from available CCD detectors. This high speed detector offers responses from one to 10 milliseconds that is much higher than the commercially available CCD detectors operating at a TV frame rate. The parallel multiple peaks thresholding detection capability makes it particularly suitable for optical correlator and optoelectronically implemented neural networks. The principle of operation, circuit design and the performance characteristics are described. Experimental demonstration of correlation peak detection is also provided. Recently, we have also designed and built an advanced version of a 64 X 64 thresholding photodetector array chip. Experimental investigation of using this chip for pattern recognition is ongoing.

Optical and electrical properties of Cu-based all oxide semi-transparent photodetector

Energy Technology Data Exchange (ETDEWEB)

Kim, Hong-Sik; Patel, Malkeshkumar; Yadav, Pankaj; Kim, Joondong, E-mail: joonkim@inu.ac.kr, E-mail: dwkim@ewha.ac.kr [Photoelectric and Energy Device Application Lab (PEDAL) and Department of Electrical Engineering, Incheon National University, 119 Academy Rd., Yeonsu, Incheon 406772 (Korea, Republic of); Sohn, Ahrum; Kim, Dong-Wook, E-mail: joonkim@inu.ac.kr, E-mail: dwkim@ewha.ac.kr [Department of Physics, Ewha Womans University, Seoul 120750 (Korea, Republic of)

2016-09-05

Zero-bias operating Cu oxide-based photodetector was achieved by using large-scale available sputtering method. Cu oxide (Cu{sub 2}O or CuO) was used as p-type transparent layer to form a heterojunction by contacting n-type ZnO layer. All metal-oxide materials were employed to realize transparent device at room temperature and showed a high transparency (>75% at 600 nm) with excellent photoresponses. The structural, morphological, optical, and electrical properties of Cu oxides of CuO and Cu{sub 2}O are evaluated in depth by UV-visible spectrometer, X-ray diffraction, scanning electron microscopy, atomic force microscopy, Kelvin probe force microscopy, and Hall measurements. We may suggest a route of high-functional Cu oxide-based photoelectric devices for the applications in flexible and transparent electronics.

Radiation Effects in Nanostructures: Comparison of Proton Irradiation Induced Changes on Quantum Dots and Quantum Wells

Science.gov (United States)

Leon, R.; Swift, G.; Magness, B.; Taylor, W.; Tang, Y.; Wang, K.; Dowd, P.; Zhang, Y.

2000-01-01

Successful implementation of technology using self-forming semiconductor Quantum Dots (QDs) has already demonstrated that temperature independent Dirac-delta density of states can be exploited in low current threshold QD lasers and QD infrared photodetectors.

Optimization of surface passivation for InGaAs/InP pin photodetectors using ammonium sulfide

International Nuclear Information System (INIS)

Sheela, D; Das Gupta, Nandita

2008-01-01

In this work, the effect of the process parameters during chemical and electrochemical passivation of InGaAs/InP PIN photodetectors using (NH 4 ) 2 S x (x >1) has been studied in detail. It has been observed that the time of passivation, temperature of the sulfide solution and illumination during electrochemical treatment play significant roles in the efficacy of the passivation process. These parameters therefore have to be carefully optimized in order to reduce the dark current of the detectors to a minimum value. The yield of the process is also found to improve with sulfur passivation

GeSn Based Near and Mid Infrared Heterostructure Detectors

Science.gov (United States)

2018-02-07

prestigious journals. 15.  SUBJECT TERMS Plasmonic Enhancement, Metal Nanostructures, CMOS, Photodetectors, Germanium-Tin Diode, IR Focal Plane Array...following features: (1) ease of manufacture in a foundry via a simple epitaxial structure, (2) end- fire coupling into on-chip transparent Ge or Si

Piezo-phototronic Effect Enhanced UV/Visible Photodetector Based on Fully Wide Band Gap Type-II ZnO/ZnS Core/Shell Nanowire Array.

Science.gov (United States)

Rai, Satish C; Wang, Kai; Ding, Yong; Marmon, Jason K; Bhatt, Manish; Zhang, Yong; Zhou, Weilie; Wang, Zhong Lin

2015-06-23

A high-performance broad band UV/visible photodetector has been successfully fabricated on a fully wide bandgap ZnO/ZnS type-II heterojunction core/shell nanowire array. The device can detect photons with energies significantly smaller (2.2 eV) than the band gap of ZnO (3.2 eV) and ZnS (3.7 eV), which is mainly attributed to spatially indirect type-II transition facilitated by the abrupt interface between the ZnO core and ZnS shell. The performance of the device was further enhanced through the piezo-phototronic effect induced lowering of the barrier height to allow charge carrier transport across the ZnO/ZnS interface, resulting in three orders of relative responsivity change measured at three different excitation wavelengths (385, 465, and 520 nm). This work demonstrates a prototype UV/visible photodetector based on the truly wide band gap semiconducting 3D core/shell nanowire array with enhanced performance through the piezo-phototronic effect.

Development of a new photo-detector readout technique for PET and CT imaging

CERN Document Server

Powolny, François; Auffray, Etiennette; Dosanjh, Manjit; Jarron, Pierre; Kaplon, Jan; Lecoq, Paul; Meyer, T C; Trummer, Julia; Velitchko, Sandra

2007-01-01

In the framework of the European FP6's BioCare project, we develop a novel photo-detector readout technique to increase sensitivity and timing precision for molecular imaging in Positron Emission Tomography (PET) and Computer Tomography (CT). Within the Project's work packages, the CERN-BioCare group focuses on the development of a PET detection head suitable to process data from both PET and CT operation in one unit. The detector module consists of a LSO matrix coupled to an APD array. The signal is processed by a fast and low noise readout electronics recently developed for experiments at the Large Hadron Collider (LHC) at CERN. The functioning of the individual system components and the performance of the entire readout channel are presented.

Sensitive, Fast, and Stable Perovskite Photodetectors Exploiting Interface Engineering

KAUST Repository

Sutherland, Brandon R.

2015-08-19

© 2015 American Chemical Society. Organometallic halide perovskites are a class of solution-processed semiconductors exhibiting remarkable optoelectronic properties. They have seen rapid strides toward enabling efficient third-generation solar cell technologies. Here, we report the first material-tailoring of TiO2/perovskite/spiro-OMeTAD junction-based photodiodes toward applications in photodetection, a field in need of fast, sensitive, low-cost, spectrally tunable materials that offer facile integration across a broad range of substrates. We report photodetection that exhibits 1 μs temporal response, and we showcase stable operation in the detection of over 7 billion transient light pulses through a continuous pulsed-illumination period. The perovskite diode photodetector has a peak responsivity approaching 0.4 A W^-1 at 600 nm wavelength, which is superior to red light detection in crystalline silicon photodiodes used in commercial image sensors. Only by developing a composite Al2O3/PCBM front contact interface layer were we able to stabilize device operation in air, reduce dark current, and enhance the responsivity in the low-bias regime to achieve an experimentally measured specific detectivity of 10¹² Jones.

Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction

International Nuclear Information System (INIS)

Seyedi, M. A.; Yao, M.; O'Brien, J.; Dapkus, P. D.; Wang, S. Y.

2013-01-01

We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7 dB for 2 V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields 2 , which shows a strong possibility for high-speed applications with a broad area device

Ultra low-noise differential ac-coupled photodetector for sensitive pulse detection applications

International Nuclear Information System (INIS)

Windpassinger, Patrick J; Boisen, Axel; Kjærgaard, Niels; Polzik, Eugene S; Müller, Jörg Helge; Kubasik, Marcin; Koschorreck, Marco

2009-01-01

We report on the performance of ultra low-noise differential photodetectors especially designed for probing of atomic ensembles with weak light pulses. The working principle of the detectors is described together with the analysis procedures employed to extract the photon shot noise of light pulses with ∼1 μs duration. As opposed to frequency response peaked detectors, our approach allows for broadband quantum noise measurements. The equivalent noise charge (ENC) for two different hardware approaches is evaluated to 280 and 340 electrons per pulse, respectively, which corresponds to a dark noise equivalent photon number of n 3dB = 0.8 × 10 5 and n 3dB = 1.2 × 10 5 in the two approaches. Finally, we discuss the possibility of removing classical correlations in the output signal caused by detector imperfection by using double-correlated sampling methods

Studies on fabrication and characterization of a high-performance Al-doped ZnO/n-Si (1 1 1) heterojunction photodetector

International Nuclear Information System (INIS)

Ismail, Raid A; Al-Naimi, Ala; Al-Ani, Alaa A

2008-01-01

ZnO:Al/c-Si (1 1 1) isotype heterojunction photodetectors were fabricated by a chemical spray pyrolysis technique. High responsivity and good junction characteristics were obtained after post-deposition rapid thermal annealing (RTA). Dark and illuminated I–V characteristics were measured and analyzed. The ideality factor was deduced from I–V characteristics and found to be 1.3 after RTA. C–V measurements revealed that the junction was abrupt type. The energyband diagram, based on the Anderson model, was constructed from the electrical properties of the junction. Good photoresponses in UV and visible regions with responsivity were around 0.1 A W −1 and 0.47 A W −1 , respectively. The rise time of the detector was improved after RTA and found to be 50 ns. These results suggest that the Al dopant could be a good choice to fabricate the doped ZnO/Si devices for photodetection and other optoelectronic applications. We describe here the fabrication process and optoelectronic characteristics of the photodetector

The Silicon:Colloidal Quantum Dot Heterojunction

KAUST Repository

Masala, Silvia; Adinolfi, Valerio; Sun, Jon Paul; Del Gobbo, Silvano; Voznyy, Oleksandr; Kramer, Illan J.; Hill, Ian G.; Sargent, Edward H.

2015-01-01

A heterojunction between crystalline silicon and colloidal quantum dots (CQDs) is realized. A special interface modification is developed to overcome an inherent energetic band mismatch between the two semiconductors, and realize the efficient collection of infrared photocarriers generated in the CQD film. This junction is used to produce a sensitive near infrared photodetector. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Silicon:Colloidal Quantum Dot Heterojunction

KAUST Repository

Masala, Silvia

2015-10-13

A heterojunction between crystalline silicon and colloidal quantum dots (CQDs) is realized. A special interface modification is developed to overcome an inherent energetic band mismatch between the two semiconductors, and realize the efficient collection of infrared photocarriers generated in the CQD film. This junction is used to produce a sensitive near infrared photodetector. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoelectrochemical-type sunlight photodetector based on MoS2/graphene heterostructure

International Nuclear Information System (INIS)

Huang, Zongyu; Han, Weijia; Chander, D Sathish; Qi, Xiang; Zhang, Han; Tang, Hongli; Ren, Long

2015-01-01

We have fabricated a novel sunlight photo-detector based on a MoS 2 /graphene heterostructure. The MoS 2 /graphene heterostructure was prepared by a facile hydrothermal method along with a subsequent annealing process followed by a substrate-induced high selective nucleation and growth mechanism. The microstructures and morphologies of the two-dimensional MoS 2 /graphene heterostructure can be experimentally confirmed by x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and a UV–vis absorption spectrometer. Photoresponse investigations performed by a photoelectrochemical (PEC) measurement system indicate that the synthesized MoS 2 /graphene heterostructure shows superior photoresponse activities under the illumination of sunlight in contrast with bare MoS 2 and graphene. The improved photoresponsivity can be attributed to the enhanced light absorption, strong light–matter interaction and the extremely efficient charge separation of the heterostructure. The structure and performances of the MoS 2 /graphene heterostructure suggest promising applications in the field of photonics and optoelectronics. (paper)

Visible Photodetectors Based on Organic-Inorganic Hybrids Using Electrostatic Spraying Technology

Directory of Open Access Journals (Sweden)

Liang-Wen Ji

2013-12-01

Full Text Available This paper discusses an organic-inorganic hybrid white photodetector with the structure of ITO /AZO/ZnO NWs:P3HT: PCBM/PEDOT: PSS/Al produced with an electrostatic spraying method. The method of production was as follows: First, different spraying methods (continuous spraying, discontinuous spraying and different spraying times were tested before the final electrostatic spraying. Then, different annealing times (10 min and 20 min were tested to anneal the coated film. Lastly, we investigated the photoelectric properties, including transparency analysis of the film surface topography through XRD, OM, FE-SEM, AFM and UV-VIS. The results showed that the detector with discontinuous spraying and 20 mins annealing had a photocurrent of approx. 22.1×10-4A, dark current (drain current of approx. 1.94×10-7A, and a ratio of photocurrent to dark current of approximately 1.14×104, which produced optimal photoelectric characteristics.

Effects of thermal annealing on the performance of Al/ZnO nanorods/Pt structure ultraviolet photodetector

International Nuclear Information System (INIS)

Zhou Hai; Fang Guojia; Liu Nishuang; Zhao Xingzhong

2011-01-01

Highlights: → Schottky barrier ultraviolet photodetectors were obtained by sputtering Pt electrode and evaporating Al electrode on the top of ZnO nanorod arrays with thermal treatment. When annealing temperature was up to 300 deg. C, the performance of the PDs was improved with the great decrease of response and recovery times. → For annealing temperature at 300 deg. C and above, the responsivity decreases with increasing annealing temperature. → The ratio of detectivity (D254* to D546*) was calculated as high as 103 for all PDs annealed at 300 deg. C and above. - Abstract: ZnO nanorod arrays were fabricated on ZnO coated glass substrate by hydrothermal method. Schottky barrier ultraviolet photodetectors (PDs) were obtained by sputtering Pt electrode and evaporating Al electrode on the top of ZnO nanorod arrays with thermal treatment. It is illustrated that Schottky contacts at the electrode/ZnO NRs interface were formed at the annealing temperature of 300 deg. C and above. When annealing temperature was up to 300 o C, the performance of the PDs was improved with the great decrease of response and recovery times. At the forward bias of 2 V, the Schottky contact PDs showed the biggest responsivity and the best detectivity at the annealing temperature of 300 deg. C. For annealing temperature at 300 deg. C and above, the responsivity decreases with increasing annealing temperature and the ratio of detectivity (D 254 * to D 546 *) was calculated as high as 10 3 for all PDs annealed at 300 deg. C and above.

Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

Directory of Open Access Journals (Sweden)

Md Rezaul Hasan

2015-10-01

Full Text Available A self-powered ultraviolet (UV photodetector (PD based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO coated plastic polyethylene terephthalate (PET substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

Energy Technology Data Exchange (ETDEWEB)

Hasan, Md Rezaul [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Xie, Ting; Liu, Guannan [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Barron, Sara C. [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Nguyen, Nhan V. [Semiconductor and Dimensional Metrology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Motayed, Abhishek [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Rao, Mulpuri V. [Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Debnath, Ratan, E-mail: ratan.debnath@nist.gov [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2015-10-01

A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

GaN membrane MSM ultraviolet photodetectors

Science.gov (United States)

Muller, A.; Konstantinidis, G.; Kostopoulos, A.; Dragoman, M.; Neculoiu, D.; Androulidaki, M.; Kayambaki, M.; Vasilache, D.; Buiculescu, C.; Petrini, I.

2006-12-01

GaN exhibits unique physical properties, which make this material very attractive for wide range of applications and among them ultraviolet detection. For the first time a MSM type UV photodetector structure was manufactured on a 2.2 μm. thick GaN membrane obtained using micromachining techniques. The low unintentionally doped GaN layer structure was grown by MOCVD on high resistivity (ρ>10kΩcm) oriented silicon wafers, 500μm thick. The epitaxially grown layers include a thin AlN layer in order to reduce the stress in the GaN layer and avoid cracking. Conventional contact lithography, e-gun Ni/Au (10nm /200nm) evaporation and lift-off techniques were used to define the interdigitated Schottky metalization on the top of the wafer. Ten digits with a width of 1μm and a length of 100μm were defined for each electrode. The distance between the digits was also 1μm. After the backside lapping of the wafer to a thickness of approximately 150μm, a 400nm thick Al layer was patterned and deposited on the backside, to be used as mask for the selective reactive ion etching of silicon. The backside mask, for the membrane formation, was patterned using double side alignment techniques and silicon was etched down to the 2.2μm thin GaN layer using SF 6 plasma. A very low dark current (30ρA at 3V) was obtained. Optical responsivity measurements were performed at 1.5V. A maximum responsivity of 18mA/W was obtained at a wavelength of 370nm. This value is very good and can be further improved using transparent contacts for the interdigitated structure.

Pseudo 2-transistor active pixel sensor using an n-well/gate-tied p-channel metal oxide semiconductor field eeffect transistor-type photodetector with built-in transfer gate

Science.gov (United States)

Seo, Sang-Ho; Seo, Min-Woong; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

2008-11-01

In this paper, a pseudo 2-transistor active pixel sensor (APS) has been designed and fabricated by using an n-well/gate-tied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector with built-in transfer gate. The proposed sensor has been fabricated using a 0.35 μm 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) logic process. The pseudo 2-transistor APS consists of two NMOSFETs and one photodetector which can amplify the generated photocurrent. The area of the pseudo 2-transistor APS is 7.1 × 6.2 μm2. The sensitivity of the proposed pixel is 49 lux/(V·s). By using this pixel, a smaller pixel area and a higher level of sensitivity can be realized when compared with a conventional 3-transistor APS which uses a pn junction photodiode.

Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction

Energy Technology Data Exchange (ETDEWEB)

Seyedi, M. A., E-mail: seyedi@usc.edu; Yao, M.; O' Brien, J.; Dapkus, P. D. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Wang, S. Y. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, California 95064, USA and NASA Ames Research Center, Moffett Field, California 94035 (United States)

2013-12-16

We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7 dB for 2 V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields <5 nF/cm{sup 2}, which shows a strong possibility for high-speed applications with a broad area device.

R&D of a pioneering system for a high resolution photodetector: The VSiPMT

Science.gov (United States)

Barbato, F. C. T.; Barbarino, G.; Campajola, L.; Di Capua, F.; Mollo, C. M.; Valentini, A.; Vivolo, D.

2017-12-01

The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists in replacing the classical dynode chain with a special SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and the stability are among the most attractive features of the VSiPMT.We now present the progress on the realization of a 1-in. prototype and the preliminary tests we are performing on it.

Enhancement of UV photodetector properties of ZnO nanorods/PEDOT:PSS Schottky junction by NGQD sensitization along with conductivity improvement of PEDOT:PSS by DMSO additive

Science.gov (United States)

Dhar, Saurab; Majumder, Tanmoy; Chakraborty, Pinak; Mondal, Suvra Prakash

2018-04-01

Schottky junction ultraviolet (UV) photodetector was fabricated by spin coating a hole conducting polymer, poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) on hydrothermally grown zinc oxide (ZnO) nanorod arrays. The UV detector performance was significantly improved two step process. Firstly, ZnO nanorods were modified by sensitizing N doped grapheme quantum dots (NGQDs) for better photoresponce behavior. Afterwards, the junction properties as well as photoresponse was enhanced by modifying electrical conductivity of PEDOT:PSS layer with organic solvent (DMSO). Our NGQD decorated ZnO NRs/DMSO-PEDOT:PSS Schottky junction device demonstrated superior external quantum efficiency (EQE ˜ 90063 %) and responsivity (Rλ˜247 A/W) at 340 nm wavelength and -1V external bias. The response and recovery times of the final photodetector device was very fast compared to GQD as well as NGQD modified and pristine ZnO nanorod based detectors.

Fabrication of high responsivity deep UV photo-detector based on Na doped ZnO nanocolumns

Science.gov (United States)

Agrawal, Jitesh; Dixit, Tejendra; Palani, I. A.; Ramachandra Rao, M. S.; Singh, Vipul

2018-05-01

We report a variety of the hydrothermally synthesized ZnO nanostructures with a significant suppression in defect-related emission and huge enhancement in the photo-current to the dark current ratio (approximately six orders of magnitude) upon UV light illumination. Interestingly, the photo-detector shows lower dark current of 1.6 nA with high responsivity of 507 A W‑1 at 254 nm. Here, a systematic analysis of the growth process as well as the physical, chemical and electrical properties of as-grown ZnO nanostructures has been performed. We have utilized the duo effect of both the inorganic (KMnO4) and organic (Na3C6H5O7) additives, which has facilitated the precise tuning of the morphology and intrinsic defects in nanostructures that have made an impact on the photo-responsivity, photoluminescence (PL) and adhesivity of the film on to the underlying substrate. PL analysis of as-grown ZnO nanostructures has suggested 11 times improvement in the near band emission (NBE) to defect level emission (DLE) ratio. Interestingly, thermal annealing of the samples has shown a dramatic change in the morphology with significant improvement in the crystallinity. Notably, the band gap was observed to be modulated from 3.3 eV to 3.1 eV after annealing. In addition to UV photo-detector based applications, the work presented here has provided a subtle solution towards the rectification of various problems pertaining to hydrothermal processes like poor adhesivity, feeble UV emission and problem in precise tuning of the morphology along with the bandgap in one go. Therefore, these investigations assume critical significance towards the development of next-generation optoelectronic devices.

2D Semiconductors for Valley-Polarized LEDs and Photodetectors

Science.gov (United States)

Yu, Ting

The recently discovered two-dimensional (2D) semiconductors, such as transitional-metal-dichalcogenide monolayers, have aroused great interest due to the underlying quantum physics and the appealing optoelectronic applications like atomically thin light-emitting diodes (LEDs) and photodetectors. On the one hand, valley-polarized electroluminescence and photocurrent from such monolayers have not caused enough attention but highly demanded as building blocks for the new generation valleytronic applications. On the other hand, most reports on these devices are based on the mechanically exfoliated small samples. Considering real applications, a strategy which could offer mass-product and high compatibility to the current planar processes is greatly demanded. Large-area samples prepared by chemical vapour deposition (CVD) are perfect candidates towards such a goal. Here, we report electrically tunable valley-polarized electroluminescence and the selective spin-valley-coupled photocurrent in optoelectronic devices based on monolayer WS2 and MoS2 grown by CVD, exhibiting large electroluminescence and photocurrent dichroisms of 81% and 60%, respectively. The controllable valley polarization and emission components of the electroluminescence have been realized by varying electrical injection of carriers. For the observed helicity-dependent photocurrent, the circular photogalvanic effect at resonant excitations has been found to take the dominant responsibility.

Measurement of the dynamic response of low-gain solid-state photodetector under weak pulse illumination

CERN Document Server

Clément, D; Morel, Christian

2000-01-01

This paper presents the development of a Tunable Light Pulse Generator built to measure the quantum efficiency of photodetectors under continuous or pulsed (20 ns FWHM) illumination as a function of wavelength in the Visible-UV region. For this purpose, a miniature Hamamatsu R5600U-04 PMT with low cathode resistivity can be used as reference detector. Dedicated electronics was developed in order to measure simultaneously the cathode and anode currents. This should allow to determine precisely the gain as a function of the high voltage applied to the PMT. Preliminary measurements using the TLPG do not demonstrate significant differences between the dynamic (approx 10 000 photons) and DC responses of PIN photodiodes down to 300 nm.

Semipolar III–nitride quantum well waveguide photodetector integrated with laser diode for on-chip photonic system

KAUST Repository

Shen, Chao

2017-02-28

A high-performance waveguide photodetector (WPD) integrated with a laser diode (LD) sharing the single InGaN/GaN quantum well active region is demonstrated on a semipolar GaN substrate. The photocurrent of the integrated WPD is effectively tuned by the emitted optical power from the LD. The responsivity ranges from 0.018 to 0.051 A/W with increasing reverse bias from 0 to 10 V. The WPD shows a large 3 dB modulation bandwidth of 230 MHz. The integrated device, being used for power monitoring and on-chip communication, paves the way towards the eventual realization of a III–nitride on-chip photonic system.

High sensitivity, fast speed and self-powered ultraviolet photodetectors based on ZnO micro/nanowire networks

Directory of Open Access Journals (Sweden)

Zhiming Bai

2014-02-01

Full Text Available Ultraviolet (UV photodetectors (PDs based on ZnO micro/nanowire (MNW networks with Pt contacts have been fabricated on glass substrates. The PDs exhibited a high photosensitivity (5×103 for 365 nm UV light with a fast recovery time (0.2 s at a reverse bias voltage of 2 V. The light induced modulation of Schottky barrier and MNW–MNW junction barrier was employed to account for the results. It was also observed that the PD had a high on–off ratio of 800 without external bias. The photovoltaic effect was proposed to explain the self-powered phenomenon.

Semipolar III–nitride quantum well waveguide photodetector integrated with laser diode for on-chip photonic system

KAUST Repository

Shen, Chao; Lee, Changmin; Stegenburgs, Edgars; Lerma, Jorge Holguin; Ng, Tien Khee; Nakamura, Shuji; DenBaars, Steven P.; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

2017-01-01

A high-performance waveguide photodetector (WPD) integrated with a laser diode (LD) sharing the single InGaN/GaN quantum well active region is demonstrated on a semipolar GaN substrate. The photocurrent of the integrated WPD is effectively tuned by the emitted optical power from the LD. The responsivity ranges from 0.018 to 0.051 A/W with increasing reverse bias from 0 to 10 V. The WPD shows a large 3 dB modulation bandwidth of 230 MHz. The integrated device, being used for power monitoring and on-chip communication, paves the way towards the eventual realization of a III–nitride on-chip photonic system.

Nanoscale resonant-cavity-enhanced germanium photodetectors with lithographically defined spectral response for improved performance at telecommunications wavelengths.

Science.gov (United States)

Balram, Krishna C; Audet, Ross M; Miller, David A B

2013-04-22

We demonstrate the use of a subwavelength planar metal-dielectric resonant cavity to enhance the absorption of germanium photodetectors at wavelengths beyond the material's direct absorption edge, enabling high responsivity across the entire telecommunications C and L bands. The resonant wavelength of the detectors can be tuned linearly by varying the width of the Ge fin, allowing multiple detectors, each resonant at a different wavelength, to be fabricated in a single-step process. This approach is promising for the development of CMOS-compatible devices suitable for integrated, high-speed, and energy-efficient photodetection at telecommunications wavelengths.

Persistent photoconductivity due to trapping of induced charges in Sn/ZnO thin film based UV photodetector

Science.gov (United States)

Yadav, Harish Kumar; Sreenivas, K.; Gupta, Vinay

2010-05-01

Photoconductivity relaxation in rf magnetron sputtered ZnO thin films integrated with ultrathin tin metal overlayer is investigated. Charge carriers induced at the ZnO-metal interface by the tin metal overlayer compensates the surface lying trap centers and leads to the enhanced photoresponse. On termination of ultraviolet radiation, recombination of the photoexcited electrons with the valence band holes leaves the excess carriers deeply trapped at the recombination center and holds the dark conductivity level at a higher value. Equilibrium between the recombination centers and valence band, due to trapped charges, eventually stimulates the persistent photoconductivity in the Sn/ZnO photodetectors.

Persistent photoconductivity due to trapping of induced charges in Sn/ZnO thin film based UV photodetector

International Nuclear Information System (INIS)

Yadav, Harish Kumar; Sreenivas, K.; Gupta, Vinay

2010-01-01

Photoconductivity relaxation in rf magnetron sputtered ZnO thin films integrated with ultrathin tin metal overlayer is investigated. Charge carriers induced at the ZnO-metal interface by the tin metal overlayer compensates the surface lying trap centers and leads to the enhanced photoresponse. On termination of ultraviolet radiation, recombination of the photoexcited electrons with the valence band holes leaves the excess carriers deeply trapped at the recombination center and holds the dark conductivity level at a higher value. Equilibrium between the recombination centers and valence band, due to trapped charges, eventually stimulates the persistent photoconductivity in the Sn/ZnO photodetectors.

Towards on-chip integration of brain imaging photodetectors using standard CMOS process.

Science.gov (United States)

Kamrani, Ehsan; Lesage, Frederic; Sawan, Mohamad

2013-01-01

The main effects of on-chip integration on the performance and efficiency of silicon avalanche photodiode (SiAPD) and photodetector front-end is addressed in this paper based on the simulation and fabrication experiments. Two different silicon APDs are fabricated separately and also integrated with a transimpedance amplifier (TIA) front-end using standard CMOS technology. SiAPDs are designed in p+/n-well structure with guard rings realized in different shapes. The TIA front-end has been designed using distributed-gain concept combined with resistive-feedback and common-gate topology to reach low-noise and high gain-bandwidth product (GBW) characteristics. The integrated SiAPDs show higher signal-to-noise ratio (SNR), sensitivity and detection efficiency comparing to the separate SiAPDs. The integration does not show a significant effect on the gain and preserves the low power consumption. Using APDs with p-well guard-ring is preferred due to the higher observed efficiency after integration.

All-Inorganic Perovskite CsPb2Br5 Microsheets for Photodetector Application

Directory of Open Access Journals (Sweden)

Xiaosheng Tang

2018-01-01

Full Text Available Lead-halide perovskites have emerged as one kind of important optoelectronic materials with excellent performance in photovoltaic and light-emitting diode applications. Herein, we reported all-inorganic perovskite CsPb2Br5 microsheets prepared by a facile injection method. Through the X-ray diffraction (XRD and Scanning Electron Microscope (SEM, it could be seen that the CsPb2Br5 microsheets showed single tetragonal crystalline phase and kept uniform square shape. Moreover, the as-synthesized CsPb2Br5 microsheets exhibited photoluminescence emission at 513 nm, and the UV–vis absorption spectrum further indicated the band gap of CsPb2Br5 microsheets was ≈2.50 eV. Additionally, the as-fabricated CsPb2Br5 microsheets based photodetector exhibited faster photoresponse characteristics of short rise time (0.71 s and decay time (0.60 s, which demonstrated its promising application as high performance electronic and optoelectronic devices.

Photoresponse properties of large area MoS2 metal–semiconductor–metal photodetectors

Science.gov (United States)

Ko, Tsung-Shine; Huang, Yu-Jen; Lin, Der-Yuh; Lin, Chia-Feng; Hong, Bo-Syun; Chen, Hone-Zern

2018-04-01

In this study, a large-area molybdenum disulfide (MoS2) thin film was obtained by low pressure thermal sulfurization. Raman scattering spectrum shows that the peaks at 374 and 403 cm‑1 are from the MoS2 thin film. XRD result reveals peaks at 33 and 58.5° indicating MoS2(100) and (110) crystal planes. By using gold (Au), silver (Ag), and aluminum (Al) as contact materials on the MoS2 thin film, photoresponsivity results indicate that Ag is a suitable material for obtaining a high responsivity for a high-performance photodetector (PD). Photocurrent mapping measurements also reveal that Ag contacts have the best carrier transport characteristic with carrier diffusion length of 101 µm among these contacts. Furthermore, we investigated metal–semiconductor–metal MoS2 thin film PDs with interdigitated fingers of 300, 400, 500, and 600 µm contact widths, which showed that the large contact widths could produce a high photoresponse for PD application owing to low resistance.

Highly Transparent, Visible-Light Photodetector Based on Oxide Semiconductors and Quantum Dots.

Science.gov (United States)

Shin, Seung Won; Lee, Kwang-Ho; Park, Jin-Seong; Kang, Seong Jun

2015-09-09

Highly transparent phototransistors that can detect visible light have been fabricated by combining indium-gallium-zinc oxide (IGZO) and quantum dots (QDs). A wide-band-gap IGZO film was used as a transparent semiconducting channel, while small-band-gap QDs were adopted to absorb and convert visible light to an electrical signal. Typical IGZO thin-film transistors (TFTs) did not show a photocurrent with illumination of visible light. However, IGZO TFTs decorated with QDs showed enhanced photocurrent upon exposure to visible light. The device showed a responsivity of 1.35×10(4) A/W and an external quantum efficiency of 2.59×10(4) under illumination by a 635 nm laser. The origin of the increased photocurrent in the visible light was the small band gap of the QDs combined with the transparent IGZO films. Therefore, transparent phototransistors based on IGZO and QDs were fabricated and characterized in detail. The result is relevant for the development of highly transparent photodetectors that can detect visible light.

Enhanced photo-response of porous silicon photo-detectors by embeddingTitanium-dioxide nano-particles

Science.gov (United States)

Ali, Hiba M.; Makki, Sameer A.; Abd, Ahmed N.

2018-05-01

Porous silicon (n-PS) films can be prepared by photoelectochemical etching (PECE) Silicon chips n - types with 15 (mA / cm2), in 15 minutes etching time on the fabrication nano-sized pore arrangement. By using X-ray diffraction measurement and atomic power microscopy characteristics (AFM), PS was investigated. It was also evaluated the crystallites size from (XRD) for the PS nanoscale. The atomic force microscopy confirmed the nano-metric size chemical fictionalization through the electrochemical etching that was shown on the PS surface chemical composition. The atomic power microscopy checks showed the roughness of the silicon surface. It is also notified (TiO2) preparation nano-particles that were prepared by pulse laser eradication in ethanol (PLAL) technique through irradiation with a Nd:YAG laser pulses TiO2 target that is sunk in methanol using 400 mJ of laser energy. It has been studied the structural, optical and morphological of TiO2NPs. It has been detected that through XRD measurement, (TiO2) NPs have been Tetragonal crystal structure. While with AFM measurements, it has been realized that the synthesized TiO2 particles are spherical with an average particle size in the (82 nm) range. It has been determined that the energy band gap of TiO2 NPs from optical properties and set to be in (5eV) range.The transmittance and reflectance spectra have determined the TiO2 NPs optical constants. It was reported the effectiveness of TiO2 NPs expansion on the PS Photodetector properties which exposes the benefits in (Al/PS/Si/Al). The built-in tension values depend on the etching time current density and laser flounce. Al/TiO2/PS/Si/Al photo-detector heterojunction have two response peaks that are situated at 350 nm and (700 -800nm) with max sensitivity ≈ 0.7 A/W. The maximum given detectivity is 9.38at ≈ 780 nm wavelength.

InAs/GaSb type-II superlattice infrared detectors: Future prospect

Science.gov (United States)

Rogalski, A.; Martyniuk, P.; Kopytko, M.

2017-09-01

Investigations of antimonide-based materials began at about the same time as HgCdTe ternary alloys—in the 1950s, and the apparent rapid success of their technology, especially low-dimensional solids, depends on the previous five decades of III-V materials and device research. However, the sophisticated physics associated with the antimonide-based bandgap engineering concept started at the beginning of 1990s gave a new impact and interest in development of infrared detector structures within academic and national laboratories. The development of InAs/GaSb type-II superlattices (T2SLs) results from two primary motivations: the perceived challenges of reproducibly fabricating high-operability HgCdTe focal plane arrays (FPAs) at reasonable cost and the theoretical predictions of lower Auger recombination for type T2SL detectors compared with HgCdTe. Second motivation—lower Auger recombination should be translated into a fundamental advantage for T2SL over HgCdTe in terms of lower dark current and/or higher operating temperature, provided other parameters such as Shockley-Read-Hall (SRH) lifetime are equal. InAs/GaSb T2SL photodetectors offer similar performance to HgCdTe at an equivalent cut-off wavelength, but with a sizeable penalty in operating temperature, due to the inherent difference in SRH lifetimes. It is predicted that since the future infrared (IR) systems will be based on the room temperature operation of depletion-current limited arrays with pixel densities that are fully consistent with background- and diffraction-limited performance due to the system optics, the material system with long SRH lifetime will be required. Since T2SLs are very much resisted in attempts to improve its SRH lifetime, currently the only material that meets this requirement is HgCdTe. Due to less ionic chemical bonding, III-V semiconductors are more robust than their II-VI counterparts. As a result, III-V-based FPAs excel in operability, spatial uniformity, temporal stability

Donor and Acceptor Polymers for Bulk Hetero Junction Solar Cell and Photodetector Applications

KAUST Repository

Cruciani, Federico

2018-04-01

Bulk heterojunction (BHJ) devices represent a very versatile family of organic cells for both the fields of solar energy conversion and photodetection. Organic photovoltaics (OPV) are an attractive alternative to their silicon-based counterparts because of their potential for low-cost roll-to-roll printing, and their intended application in light-weight mechanically conformable devices and in window-type semi-transparent PV modules. Of all proposed OPV candidates, polymer donor with different absorption range are especially promising when used in conjunction with complementary absorbing acceptor materials, like fullerene derivatives (PCBM), conjugated molecules or polymers, achieving nowadays power conversion efficiencies (PCEs) in the range of 10-13% and being a step closer to practical applications. Among the photodetectors (PD), low band gap polymer blended with PCBM decked out the attention, given their extraordinary range of detection from UV to IR and high detectivity values reached so far, compared to the inorganic devices. Since the research has been focused on the enhancement of those numbers for an effective commercialization of organic cells, the topic of the following thesis has been centered on the synthesis of different polymer structures with diverse absorption ranges, used as donor or acceptor, with emphasis on performance in various BHJ devices either for solar cells and photodetectors. In the first part, two new wide band gap polymers, used as donor material in BHJ devices blended with fullerene and small molecule acceptors, are presented. The PBDT_2FT and PBDTT_2FT have shown nice efficiencies from 7% to 9.8%. The device results are implemented with a morphology study and a specific application in a semi-transparent tandem device, reaching a record PCE of 5.4% for average level of transparency of 48%. In another section two new low band gap polymers (Eopt~ 1.26 eV) named DTP_2FBT and (Eopt~ 1.1 eV) named BDTT_BTQ are presented. While the DTP

CdHgTe heterostructures for new-generation IR photodetectors operating at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Varavin, V. S.; Vasilyev, V. V.; Guzev, A. A.; Dvoretsky, S. A.; Kovchavtsev, A. P.; Marin, D. V.; Sabinina, I. V.; Sidorov, Yu. G.; Sidorov, G. Yu.; Tsarenko, A. V.; Yakushev, M. V., E-mail: yakushev@isp.nsc.ru [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2016-12-15

The parameters of multilayer Cd{sub x}Hg{sub 1–x}Te heterostructures for photodetectors operating at wavelengths of up to 5 μm, grown by molecular-beam epitaxy (MBE) on silicon substrates, are studied. The passivating properties of thin CdTe layers on the surface of these structures are analyzed by measuring the C–V characteristics. The temperature dependences of the minority carrier lifetime in the photoabsorption layer after growth and thermal annealing are investigated. Samples of p{sup +}–n-type photodiodes are fabricated by the implantation of arsenic ions into n-type layers, doped with In to a concentration of (1–5) × 10{sup 15} cm{sup –3}. The temperature dependences of the reverse currents are measured at several bias voltages; these currents turn out to be almost two orders of magnitude lower than those for n{sup +}–p-type diodes.

Infrared astronomy

International Nuclear Information System (INIS)

Setti, G.; Fazio, G.

1978-01-01

This volume contains lectures describing the important achievements in infrared astronomy. The topics included are galactic infrared sources and their role in star formation, the nature of the interstellar medium and galactic structure, the interpretation of infrared, optical and radio observations of extra-galactic sources and their role in the origin and structure of the universe, instrumental techniques and a review of future space observations. (C.F.)

A self-powered nano-photodetector based on PFH/ZnO nanorods organic/inorganic heterojunction

Science.gov (United States)

Li, Xiaoyun; Liu, Wei; Li, Peigang; Song, Jia; An, Yuehua; Shen, Jingqin; Wang, Shunli; Guo, Daoyou

2018-03-01

PFH/ZnO nanorods heterojunctions were fabricated by spin-coating p-type Poly (9,9-dihexylfluorene) (PFH) on n-type vertically aligned ZnO nanorod arrays grown by a facile hydrothermal method on indium tin oxide (ITO) transparent conductive glass. A typical p-n junction behavior was observed in the fabricated heterojunction. The current of heterojunction increases and decreases dramatically by switching the illumination on and off at zero bias, showing potential self-powered photodetector applications. The heterojunction were capable of generating negative current when illuminated under an appropriate wavelength. The photoresponse properties of the heterojunction can be tuned by the applied bias. In vacuum, the rectifying behavior disappeared, and show only simple semiconductor behavior. Band structure of the heterojunction was schematic drawn and explain the mechanism of the properties of PFH/ZnO nanorods heterojunctions.

A self-powered nano-photodetector based on PFH/ZnO nanorods organic/inorganic heterojunction

Directory of Open Access Journals (Sweden)

Xiaoyun Li

2018-03-01

Full Text Available PFH/ZnO nanorods heterojunctions were fabricated by spin-coating p-type Poly (9,9-dihexylfluorene (PFH on n-type vertically aligned ZnO nanorod arrays grown by a facile hydrothermal method on indium tin oxide (ITO transparent conductive glass. A typical p-n junction behavior was observed in the fabricated heterojunction. The current of heterojunction increases and decreases dramatically by switching the illumination on and off at zero bias, showing potential self-powered photodetector applications. The heterojunction were capable of generating negative current when illuminated under an appropriate wavelength. The photoresponse properties of the heterojunction can be tuned by the applied bias. In vacuum, the rectifying behavior disappeared, and show only simple semiconductor behavior. Band structure of the heterojunction was schematic drawn and explain the mechanism of the properties of PFH/ZnO nanorods heterojunctions.

Studies of a hybrid avalanche photo-detector in magnetic field

Energy Technology Data Exchange (ETDEWEB)

Šantelj, L., E-mail: luka.santelj@kek.jp [High Energy Accelerator Research Organization (KEK) (Japan); Adachi, I. [High Energy Accelerator Research Organization (KEK) (Japan); Sokendai University (Japan); Hataya, K. [Tokyo Metropolitan University (Japan); Iori, S. [Toho University (Japan); Iwata, S.; Kakuno, H. [Tokyo Metropolitan University (Japan); Kataura, R. [Niigata University (Japan); Kawai, H. [Chiba University (Japan); Kindo, H. [Sokendai University (Japan); Korpar, S. [University of Maribor (Slovenia); Jožef Stefan Institute, Ljubljana (Slovenia); Križan, P. [Jožef Stefan Institute, Ljubljana (Slovenia); University of Ljubljana (Slovenia); Mrvar, M. [Jožef Stefan Institute, Ljubljana (Slovenia); Nath, K. [Indian Institute of Technology Guwahati (India); Nishida, S. [High Energy Accelerator Research Organization (KEK) (Japan); Sokendai University (Japan); Ogawa, S. [Niigata University (Japan); Pestotnik, R.; Stanovnik, A.; Seljak, A. [Jožef Stefan Institute, Ljubljana (Slovenia); Sumiyoshi, T. [Tokyo University of Science, Tokyo (Japan); Tabata, M. [Chiba University (Japan); and others

2017-02-11

For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward endcap region of the spectrometer. The main challenge was the development of a reliable multichannel sensor for single photons that operates in the high magnetic field of the spectrometer (1.5 T) and withstands the radiation levels expected at the experiment. A 144-channel Hybrid Avalanche Photo-Detector (HAPD) was developed with Hamamatsu Photonics K.K. and the mass production of ∼480 HAPDs was completed recently. While our first tests of HAPD performance in the magnetic field (before mass production) showed no issues, we lately observed a presence of very large signal pulses (∼5000× single photon signal), generated internally within about 20% of HAPDs, while operating in the magnetic field. The rate of these pulses varies from sample to sample. These pulses impact the HAPD performance in two ways: they introduce periods of dead time and, in some cases, damage to the front-end electronics was observed. Here we present conditions under which such large pulses are generated, their properties and impact on HAPD performance, and discuss possible mechanism of their origin.

Amorphous indium-gallium-zinc-oxide as electron transport layer in organic photodetectors

International Nuclear Information System (INIS)

Arora, H.; Malinowski, P. E.; Chasin, A.; Cheyns, D.; Steudel, S.; Schols, S.; Heremans, P.

2015-01-01

Amorphous indium-gallium-zinc-oxide (a-IGZO) is demonstrated as an electron transport layer (ETL) in a high-performance organic photodetector (OPD). Dark current in the range of 10 nA/cm 2 at a bias voltage of −2 V and a high photoresponse in the visible spectrum were obtained in inverted OPDs with poly(3-hexylthiophene) and phenyl-C 61 -butyric acid methyl ester active layer. The best results were obtained for the optimum a-IGZO thickness of 7.5 nm with specific detectivity of 3 × 10 12 Jones at the wavelength of 550 nm. The performance of the best OPD devices using a-IGZO was shown to be comparable to state-of-the-art devices based on TiO x as ETL, with higher rectification achieved in reverse bias. Yield and reproducibility were also enhanced with a-IGZO, facilitating fabrication of large area OPDs. Furthermore, easier integration with IGZO-based readout backplanes can be envisioned, where the channel material can be used as photodiode buffer layer after additional treatment

Amorphous indium-gallium-zinc-oxide as electron transport layer in organic photodetectors

Energy Technology Data Exchange (ETDEWEB)

Arora, H. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Phelma–Grenoble INP, 3 Parvis Louis Néel, 38016 Grenoble Cedex 01 (France); Malinowski, P. E., E-mail: pawel.malinowski@imec.be; Chasin, A.; Cheyns, D.; Steudel, S.; Schols, S. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Heremans, P. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); ESAT, Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium)

2015-04-06

Amorphous indium-gallium-zinc-oxide (a-IGZO) is demonstrated as an electron transport layer (ETL) in a high-performance organic photodetector (OPD). Dark current in the range of 10 nA/cm{sup 2} at a bias voltage of −2 V and a high photoresponse in the visible spectrum were obtained in inverted OPDs with poly(3-hexylthiophene) and phenyl-C{sub 61}-butyric acid methyl ester active layer. The best results were obtained for the optimum a-IGZO thickness of 7.5 nm with specific detectivity of 3 × 10{sup 12} Jones at the wavelength of 550 nm. The performance of the best OPD devices using a-IGZO was shown to be comparable to state-of-the-art devices based on TiO{sub x} as ETL, with higher rectification achieved in reverse bias. Yield and reproducibility were also enhanced with a-IGZO, facilitating fabrication of large area OPDs. Furthermore, easier integration with IGZO-based readout backplanes can be envisioned, where the channel material can be used as photodiode buffer layer after additional treatment.

Boosting Two-Dimensional MoS2/CsPbBr3 Photodetectors via Enhanced Light Absorbance and Interfacial Carrier Separation.

Science.gov (United States)

Song, Xiufeng; Liu, Xuhai; Yu, Dejian; Huo, Chengxue; Ji, Jianping; Li, Xiaoming; Zhang, Shengli; Zou, Yousheng; Zhu, Gangyi; Wang, Yongjin; Wu, Mingzai; Xie, An; Zeng, Haibo

2018-01-24

Transition metal dichalcogenides (TMDs) are promising candidates for flexible optoelectronic devices because of their special structures and excellent properties, but the low optical absorption of the ultrathin layers greatly limits the generation of photocarriers and restricts the performance. Here, we integrate all-inorganic perovskite CsPbBr 3 nanosheets with MoS 2 atomic layers and take the advantage of the large absorption coefficient and high quantum efficiency of the perovskites, to achieve excellent performance of the TMD-based photodetectors. Significantly, the interfacial charge transfer from the CsPbBr 3 to the MoS 2 layer has been evidenced by the observed photoluminescence quenching and shortened decay time of the hybrid MoS 2 /CsPbBr 3 . Resultantly, such a hybrid MoS 2 /CsPbBr 3 photodetector exhibits a high photoresponsivity of 4.4 A/W, an external quantum efficiency of 302%, and a detectivity of 2.5 × 10 10 Jones because of the high efficient photoexcited carrier separation at the interface of MoS 2 and CsPbBr 3 . The photoresponsivity of this hybrid device presents an improvement of 3 orders of magnitude compared with that of a MoS 2 device without CsPbBr 3 . The response time of the device is also shortened from 65.2 to 0.72 ms after coupling with MoS 2 layers. The combination of the all-inorganic perovskite layer with high photon absorption and the carrier transport TMD layer may pave the way for novel high-performance optoelectronic devices.

Growth and characterization of β-Ga2O3 thin films by molecular beam epitaxy for deep-UV photodetectors

Science.gov (United States)

Ghose, Susmita; Rahman, Shafiqur; Hong, Liang; Rojas-Ramirez, Juan Salvador; Jin, Hanbyul; Park, Kibog; Klie, Robert; Droopad, Ravi

2017-09-01

The growth of high quality epitaxial beta-gallium oxide (β-Ga2O3) using a compound source by molecular beam epitaxy has been demonstrated on c-plane sapphire (Al2O3) substrates. The compound source provides oxidized gallium molecules in addition to oxygen when heated from an iridium crucible in a high temperature effusion cell enabling a lower heat of formation for the growth of Ga2O3, resulting in a more efficient growth process. This source also enabled the growth of crystalline β-Ga2O3 without the need for additional oxygen. The influence of the substrate temperatures on the crystal structure and quality, chemical bonding, surface morphology, and optical properties has been systematically evaluated by x-ray diffraction, scanning transmission electron microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, spectroscopic ellipsometry, and UV-vis spectroscopy. Under optimized growth conditions, all films exhibited pure (" separators="|2 ¯01 ) oriented β-Ga2O3 thin films with six-fold rotational symmetry when grown on a sapphire substrate. The thin films demonstrated significant absorption in the deep-ultraviolet (UV) region with an optical bandgap around 5.0 eV and a refractive index of 1.9. A deep-UV photodetector fabricated on the high quality β-Ga2O3 thin film exhibits high resistance and small dark current (4.25 nA) with expected photoresponse for 254 nm UV light irradiation suggesting that the material grown using the compound source is a potential candidate for deep-ultraviolet photodetectors.

Photographic infrared spectroscopy and near infrared photometry of Be stars

International Nuclear Information System (INIS)

Swings, J.P.

1976-01-01

Two topics are tackled in this presentation: spectroscopy and photometry. The following definitions are chosen: photographic infrared spectroscopy (wavelengths Hα<=lambda<1.2 μ); near infrared photometry (wavebands: 1.6 μ<=lambda<=20 μ). Near infrared spectroscopy and photometry of classical and peculiar Be stars are discussed and some future developments in the field are outlined. (Auth.)

InGaAs/GaAsSb Type-II superlattice based photodiodes for short wave infrared detection

Science.gov (United States)

Uliel, Y.; Cohen-Elias, D.; Sicron, N.; Grimberg, I.; Snapi, N.; Paltiel, Y.; Katz, M.

2017-08-01

Short Wave Infra-Red (SWIR) photodetectors operating above the response cutoff of InGaAs- based detectors (1.7-2.5 μm) are required for both defense and civil applications. Type II Super-Lattices (T2SL) were recently proposed For near- room temperature SWIR detection as a possible system enabling bandgap adjustment in the required range. The work presented here focuses on a T2SL with alternating nano-layers of InGaAs and GaAsSb lattice-matched to an InP substrate. A near room temperature SWIR cutoff of 2.4 μm was measured. Electrical junctions were realized using Zn diffusion p-doping process. We realized and studied both mesa- and selective diffusion- based p-i-n photodiodes. Dark currents of mesa-based devices were 1.5 mA/cm2 and 32 μA/cm2 at 300 and 230 K respectively. Dark currents were reduced to 1.2 mA/cm2 and 12 μA/cm2 respectively by utilizing the selective diffusion process. The effect of operating voltage is discussed. At 300 K the quantum efficiency was up to 40% at 2.18 μm in mesa devices. D∗ was 1.7 ×1010cm ·√{Hz } /W at 2 μm.

Measures of star formation rates from infrared (Herschel) and UV (GALEX) emissions of galaxies in the HerMES fields

Science.gov (United States)

Buat, V.; Giovannoli, E.; Burgarella, D.; Altieri, B.; Amblard, A.; Arumugam, V.; Aussel, H.; Babbedge, T.; Blain, A.; Bock, J.; Boselli, A.; Castro-Rodríguez, N.; Cava, A.; Chanial, P.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dwek, E.; Eales, S.; Elbaz, D.; Fox, M.; Franceschini, A.; Gear, W.; Glenn, J.; Griffin, M.; Halpern, M.; Hatziminaoglou, E.; Heinis, S.; Ibar, E.; Isaak, K.; Ivison, R. J.; Lagache, G.; Levenson, L.; Lonsdale, C. J.; Lu, N.; Madden, S.; Maffei, B.; Magdis, G.; Mainetti, G.; Marchetti, L.; Morrison, G. E.; Nguyen, H. T.; O'Halloran, B.; Oliver, S. J.; Omont, A.; Owen, F. N.; Page, M. J.; Pannella, M.; Panuzzo, P.; Papageorgiou, A.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rigopoulou, D.; Rizzo, D.; Roseboom, I. G.; Rowan-Robinson, M.; Sánchez Portal, M.; Schulz, B.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Strazzullo, V.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vaccari, M.; Valiante, E.; Valtchanov, I.; Vigroux, L.; Wang, L.; Ward, R.; Wright, G.; Xu, C. K.; Zemcov, M.

2010-11-01

The reliability of infrared (IR) and ultraviolet (UV) emissions to measure star formation rates (SFRs) in galaxies is investigated for a large sample of galaxies observed with the Spectral and Photometric Imaging Receiver (SPIRE) and the Photodetector Array Camera and Spectrometer (PACS) instruments on Herschel as part of the Herschel Multi-Tiered Extragalactic Survey (HerMES) project. We build flux-limited 250-μm samples of sources at redshift z 500 μm. Dust attenuation is discussed on the basis of commonly used diagnostics: the LIR/LUV ratio and the slope, β, of the UV continuum. A mean dust attenuation AUV of mag is measured in the samples. LIR/LUV is found to correlate with LIR. Galaxies with and 0.5 recipe commonly applied to local starbursts is found to overestimate the dust attenuation correction in our galaxy sample by a factor of ~2-3. The SFRs deduced from LIR are found to account for about 90 per cent of the total SFR; this percentage drops to 71 per cent for galaxies with (or ). For these faint objects, one needs to combine UV and IR emissions to obtain an accurate measure of the SFR.

Heterogenous integration of a thin-film GaAs photodetector and a microfluidic device on a silicon substrate

International Nuclear Information System (INIS)

Song, Fuchuan; Xiao, Jing; Udawala, Fidaali; Seo, Sang-Woo

2011-01-01

In this paper, heterogeneous integration of a III–V semiconductor thin-film photodetector (PD) with a microfluidic device is demonstrated on a SiO 2 –Si substrate. Thin-film format of optical devices provides an intimate integration of optical functions with microfluidic devices. As a demonstration of a multi-material and functional system, the biphasic flow structure in the polymeric microfluidic channels was co-integrated with a III–V semiconductor thin-film PD. The fluorescent drops formed in the microfluidic device are successfully detected with an integrated thin-film PD on a silicon substrate. The proposed three-dimensional integration structure is an alternative approach to combine optical functions with microfluidic functions on silicon-based electronic functions.

Engineering the temporal response of photoconductive photodetectors via selective introduction of surface trap states.

Science.gov (United States)

Konstantatos, Gerasimos; Levina, Larissa; Fischer, Armin; Sargent, Edward H

2008-05-01

Photoconductive photodetectors fabricated using simple solution-processing have recently been shown to exhibit high gains (>1000) and outstanding sensitivities ( D* > 10(13) Jones). One ostensible disadvantage of exploiting photoconductive gain is that the temporal response is limited by the release of carriers from trap states. Here we show that it is possible to introduce specific chemical species onto the surfaces of colloidal quantum dots to produce only a single, desired trap state having a carefully selected lifetime. In this way we demonstrate a device that exhibits an attractive photoconductive gain (>10) combined with a response time ( approximately 25 ms) useful in imaging. We achieve this by preserving a single surface species, lead sulfite, while eliminating lead sulfate and lead carboxylate. In doing so we preserve the outstanding sensitivity of these devices, achieving a specific detectivity of 10(12) Jones in the visible, while generating a temporal response suited to imaging applications.

Improved performance of In0.83Ga0.17As/InP photodetectors through modifying the position of In0.66Ga0.34As/InAs superlattice electron barrier

Science.gov (United States)

Shi, Yan-hui; Zhang, Yong-gang; Ma, Ying-jie; Gu, Yi; Chen, Xing-you; Gong, Qian; Du, Ben; Zhang, Jian; Zhu, Yi

2018-03-01

The performance of wavelength extended In0.83Ga0.17As/InP photodetectors has been improved notably through modifying the position of electron barriers in absorption layer. In order to fully utilize the diffusion component of the photocurrent, the In0.66Ga0.34As/InAs superlattice electron barrier is moved to the edge of the depletion region. Enhanced peak photo responsivity up to 0.84 A/W is realized, which raises 24% compared to that of a reference detector with the superlattice barrier in the middle of the absorber. The dark current slightly increases by 25% at room temperature while decreases by more than an order of magnitude at 150 K, resulting in about 10% or more than twofold improvements for the detectivity, respectively. The results suggest that optimized barrier position is a necessity for barrier-type photodetectors to achieve better performances.

100-Gb/s 80-km transmission of PIM-SSB-OFDM at C-band using a single-end photodetector

Science.gov (United States)

Huo, Jiahao; Zhou, Xian; Zhong, Kangping; Gui, Tao; Tan, Fengze; Tu, Jiajing; Yuan, Jinhui; Zhang, Hongyu; Long, Keping; Yu, Changyuan; Lau, Alan Pak Tao; Lu, Chao

2017-10-01

Polarization-interleave-multiplexed (PIM) with single-sideband orthogonal frequency-division multiplexing (SSB-OFDM) based on direct detection is proposed for short-reach applications transmitted up to 80 km in which the guard band can be shared for the two SSB signals with interleave electrical center frequencies. Based on two dual-drive Mach-Zehnder modulators with one single-end photodetector (PD), 100-Gb/s PIM-SSB-OFDM transmission over a 80-km standard single-mode fiber is successfully demonstrated. After 80-km transmission, the optical signal-to-noise ratio requirement is 29.1 dB with respect to the bit error rate threshold of 7% hard decision-forward error correction overhead.

Extragalactic infrared astronomy

International Nuclear Information System (INIS)

Gondhalekar, P.M.

1985-05-01

The paper concerns the field of Extragalactic Infrared Astronomy, discussed at the Fourth RAL Workshop on Astronomy and Astrophysics. Fifteen papers were presented on infrared emission from extragalactic objects. Both ground-(and aircraft-) based and IRAS infrared data were reviewed. The topics covered star formation in galaxies, active galactic nuclei and cosmology. (U.K.)

Infrared thermography

CERN Document Server

Meola, Carosena

2012-01-01

This e-book conveys information about basic IRT theory, infrared detectors, signal digitalization and applications of infrared thermography in many fields such as medicine, foodstuff conservation, fluid-dynamics, architecture, anthropology, condition monitoring, non destructive testing and evaluation of materials and structures.

Broadband infrared beam splitter for spaceborne interferometric infrared sounder.

Science.gov (United States)

Yu, Tianyan; Liu, Dingquan; Qin, Yang

2014-10-01

A broadband infrared beam splitter (BS) on ZnSe substrate used for the spaceborne interferometric infrared sounder (SIIRS) is studied in the spectral range of 4.44-15 μm. Both broadband antireflection coating and broadband beam-splitter coating in this BS are designed and tested. To optimize the optical properties and the stability of the BS, suitable infrared materials were selected, and improved deposition techniques were applied. The designed structures matched experimental data well, and the properties of the BS met the application specification of SIIRS.

Dual-Phase CsPbBr3 -CsPb2 Br5 Perovskite Thin Films via Vapor Deposition for High-Performance Rigid and Flexible Photodetectors.

Science.gov (United States)

Tong, Guoqing; Li, Huan; Li, Danting; Zhu, Zhifeng; Xu, Enze; Li, Guopeng; Yu, Linwei; Xu, Jun; Jiang, Yang

2018-02-01

Inorganic perovskites with special semiconducting properties and structures have attracted great attention and are regarded as next generation candidates for optoelectronic devices. Herein, using a physical vapor deposition process with a controlled excess of PbBr 2 , dual-phase all-inorganic perovskite composite CsPbBr 3 -CsPb 2 Br 5 thin films are prepared as light-harvesting layers and incorporated in a photodetector (PD). The PD has a high responsivity and detectivity of 0.375 A W -1 and 10 11 Jones, respectively, and a fast response time (from 10% to 90% of the maximum photocurrent) of ≈280 µs/640 µs. The device also shows an excellent stability in air for more than 65 d without encapsulation. Tetragonal CsPb 2 Br 5 provides satisfactory passivation to reduce the recombination of the charge carriers, and with its lower free energy, it enhances the stability of the inorganic perovskite devices. Remarkably, the same inorganic perovskite photodetector is also highly flexible and exhibits an exceptional bending performance (>1000 cycles). These results highlight the great potential of dual-phase inorganic perovskite films in the development of optoelectronic devices, especially for flexible device applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hadron calorimeter (PSD) with new photo-detectors (MPPC) in NA61 experiment at CERN

Science.gov (United States)

Golubeva, M.; Guber, F.; Ivashkin, A.; Izvestnyy, A.; Kurepin, A.; Morozov, S.; Petukhov, O.; Selyuzhenkov, I.; Svintsov, I.; Taranenko, A.

2017-01-01

The Projectile Spectator Detector (PSD) is a segmented hadron calorimeter used in NA61 experiment (CERN) to determine a collision centrality as well as an event plane orientation in nucleus-nucleus collisions. The main goal of the experiment includes studying the onset of de-confinement and searching for the critical point of strongly interacting matter. It is of crucial importance to have a precise characterization of the event class with the PSD for the analysis of event-by-event observables. The PSD has been already used for centrality selection on trigger level in measurements of Be+Be and Ar+Sc reactions at beam energies 13 - 158 AGeV and Pb+Pb reaction at beam energy 30 AGeV. In 2016, the central modules of PSD have been equipped with new Hamamatsu MPPC silicon photo-detectors in order to extend dynamic range for studying Pb+Pb reaction at the full energy range 13 - 158 AGeV. Results of the PSD response on proton and lead beams are presented.

Heterostructured ZnS/InP nanowires for rigid/flexible ultraviolet photodetectors with enhanced performance.

Science.gov (United States)

Zhang, Kai; Ding, Jia; Lou, Zheng; Chai, Ruiqing; Zhong, Mianzeng; Shen, Guozhen

2017-10-19

Heterostructured ZnS/InP nanowires, composed of single-crystalline ZnS nanowires coated with a layer of InP shell, were synthesized via a one-step chemical vapor deposition process. As-grown heterostructured ZnS/InP nanowires exhibited an ultrahigh I on /I off ratio of 4.91 × 10 3 , a high photoconductive gain of 1.10 × 10 3 , a high detectivity of 1.65 × 10 13 Jones and high response speed even in the case of very weak ultraviolet light illumination (1.87 μW cm -2 ). The values are much higher than those of previously reported bare ZnS nanowires owing to the formation of core/shell heterostructures. Flexible ultraviolet photodetectors were also fabricated with the heterostructured ZnS/InP nanowires, which showed excellent mechanical flexibility, electrical stability and folding endurance besides excellent photoresponse properties. The results elucidated that the heterostructured ZnS/InP nanowires could find good applications in next generation flexible optoelectronic devices.

Directional Growth of Ultralong CsPbBr3 Perovskite Nanowires for High-Performance Photodetectors.

Science.gov (United States)

Shoaib, Muhammad; Zhang, Xuehong; Wang, Xiaoxia; Zhou, Hong; Xu, Tao; Wang, Xiao; Hu, Xuelu; Liu, Huawei; Fan, Xiaopeng; Zheng, Weihao; Yang, Tiefeng; Yang, Shuzhen; Zhang, Qinglin; Zhu, Xiaoli; Sun, Litao; Pan, Anlian

2017-11-08

Directional growth of ultralong nanowires (NWs) is significant for practical application of large-scale optoelectronic integration. Here, we demonstrate the controlled growth of in-plane directional perovskite CsPbBr 3 NWs, induced by graphoepitaxial effect on annealed M-plane sapphire substrates. The wires have a diameter of several hundred nanometers, with lengths up to several millimeters. Microstructure characterization shows that CsPbBr 3 NWs are high-quality single crystals, with smooth surfaces and well-defined cross section. The NWs have very strong band-edge photoluminescence (PL) with a long PL lifetime of ∼25 ns and can realize high-quality optical waveguides. Photodetectors constructed on these individual NWs exhibit excellent photoresponse with an ultrahigh responsivity of 4400 A/W and a very fast response speed of 252 μs. This work presents an important step toward scalable growth of high-quality perovskite NWs, which will provide promising opportunities in constructing integrated nanophotonic and optoelectronic systems.

Performance improvement induced by asymmetric Y2O3-coated device structure to carbon-nanotube-film based photodetectors

Science.gov (United States)

Wang, Fanglin; Xu, Haitao; Huang, Huixin; Ma, Ze; Wang, Sheng; Peng, Lian-Mao

2017-11-01

Film-based semiconducting carbon nanotube (CNT) photodetectors are promising candidates for industrial applications. However, unintentional doping from the environment such as water/oxygen (H2O/O2) redox, polymers, etc. changes the doping level of the CNT film. Here, we evaluate the performance of film-based barrier-free bipolar diodes (BFBDs), which are basically semiconducting CNT films asymmetrically contacted by perfect n-type ohmic contact (scandium, Sc) and p-type ohmic contact (palladium, Pd) at the two ends of the diode. We show that normal BFBD devices have large variances of forward current, reverse current, and photocurrent for different doping levels of the channel. We propose an asymmetric Y2O3-coated BFBD device in which the channel is covered by a layer of an Y2O3 film and an overlap between the Sc electrode and the Y2O3 film is designed. The Y2O3 film provides p-type doping to the channel. The overlap section increases the length of the base of the pn junction, and the diffusion current of holes is suppressed. In this way, the rectifier factors (current ratio when voltages are at +0.5 V and -0.5 V) of the asymmetric Y2O3-coated BFBD devices are around two orders of magnitude larger and the photocurrent generation is more stable compared to that of normal devices. Our results provide a way to conquer the influence of unintentional doping from the environment and suppress reverse current in pn diodes. This is beneficial to applications of CNT-based photodetectors and of importance for inspiring methods to improve the performances of devices based on other low dimensional materials.

Responsivity Dependent Anodization Current Density of Nanoporous Silicon Based MSM Photodetector

Directory of Open Access Journals (Sweden)

Batool Eneaze B. Al-Jumaili

2016-01-01

Full Text Available Achieving a cheap and ultrafast metal-semiconductor-metal (MSM photodetector (PD for very high-speed communications is ever-demanding. We report the influence of anodization current density variation on the response of nanoporous silicon (NPSi based MSM PD with platinum (Pt contact electrodes. Such NPSi samples are grown from n-type Si (100 wafer using photoelectrochemical etching with three different anodization current densities. FESEM images of as-prepared samples revealed the existence of discrete pores with spherical and square-like shapes. XRD pattern displayed the growth of nanocrystals with (311 lattice orientation. The nanocrystallite sizes obtained using Scherrer formula are found to be between 20.8 nm and 28.6 nm. The observed rectifying behavior in the I-V characteristics is ascribed to the Pt/PSi/n-Si Schottky barrier formation, where the barrier height at the Pt/PSi interface is estimated to be 0.69 eV. Furthermore, this Pt/PSi/Pt MSM PD achieved maximum responsivity of 0.17 A/W and quantum efficiency as much as 39.3%. The photoresponse of this NPSi based MSM PD demonstrated excellent repeatability, fast response, and enhanced saturation current with increasing anodization current density.

Topological Insulator Bi2Se3/Si-Nanowire-Based p-n Junction Diode for High-Performance Near-Infrared Photodetector.

Science.gov (United States)

Das, Biswajit; Das, Nirmalya S; Sarkar, Samrat; Chatterjee, Biplab K; Chattopadhyay, Kalyan K

2017-07-12

Chemically derived topological insulator Bi 2 Se 3 nanoflake/Si nanowire (SiNWs) heterojunctions were fabricated employing all eco-friendly cost-effective chemical route for the first time. X-ray diffraction studies confirmed proper phase formation of Bi 2 Se 3 nanoflakes. The morphological features of the individual components and time-evolved hybrid structures were studied using field emission scanning electron microscope. High resolution transmission electron microscopic studies were performed to investigate the actual nature of junction whereas elemental distributions at junction, along with overall stoichiometry of the samples were analyzed using energy dispersive X-ray studies. Temperature dependent current-voltage characteristics and variation of barrier height and ideality factor was studied between 50 and 300 K. An increase in barrier height and decrease in the ideality factor were observed with increasing temperature for the sample. The rectification ratio (I + /I - ) for SiNWs substrate over pristine Si substrate under dark and near-infrared (NIR) irradiation of 890 nm was found to be 3.63 and 10.44, respectively. Furthermore, opto-electrical characterizations were performed for different light power intensities and highest photo responsivity and detectivity were determined to be 934.1 A/W and 2.30 × 10 13 Jones, respectively. Those values are appreciably higher than previous reports for topological insulator based devices. Thus, this work establishes a hybrid system based on topological insulator Bi 2 Se 3 nanoflake and Si nanowire as the newest efficient candidate for advanced optoelectronic materials.

Microtextured Silicon Surfaces for Detectors, Sensors & Photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Carey, JE; Mazur, E

2005-05-19

With support from this award we studied a novel silicon microtexturing process and its application in silicon-based infrared photodetectors. By irradiating the surface of a silicon wafer with intense femtosecond laser pulses in the presence of certain gases or liquids, the originally shiny, flat surface is transformed into a dark array of microstructures. The resulting microtextured surface has near-unity absorption from near-ultraviolet to infrared wavelengths well below the band gap. The high, broad absorption of microtextured silicon could enable the production of silicon-based photodiodes for use as inexpensive, room-temperature multi-spectral photodetectors. Such detectors would find use in numerous applications including environmental sensors, solar energy, and infrared imaging. The goals of this study were to learn about microtextured surfaces and then develop and test prototype silicon detectors for the visible and infrared. We were extremely successful in achieving our goals. During the first two years of this award, we learned a great deal about how microtextured surfaces form and what leads to their remarkable optical properties. We used this knowledge to build prototype detectors with high sensitivity in both the visible and in the near-infrared. We obtained room-temperature responsivities as high as 100 A/W at 1064 nm, two orders of magnitude higher than standard silicon photodiodes. For wavelengths below the band gap, we obtained responsivities as high as 50 mA/W at 1330 nm and 35 mA/W at 1550 nm, close to the responsivity of InGaAs photodiodes and five orders of magnitude higher than silicon devices in this wavelength region.

The Role of Ge Wetting Layer and Ge Islands in Si MSM Photodetectors

International Nuclear Information System (INIS)

Mahmodi, H.; Hashim, M. R.

2010-01-01

In this work, Ge thin films were deposited on silicon substrates by radio frequency magnetron sputtering to form Ge islands from Ge layer on Si substrate during post-growth rapid thermal annealing (RTA). The size of the islands decreases from 0.6 to 0.1 as the rapid thermal annealing time increases from 30 s to 60 s at 900 deg. C. Not only that the annealing produces Ge islands but also wetting layer. Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM) were employed for structural analysis of Ge islands. Metal-Semiconductor-Metal photodetectors (MSM PDs) were fabricated on Ge islands (and wetting layer)/Si. The Ge islands and wetting layer between the contacts of the fabricated devices are etched in order to see their effects on the device. The performance of the Ge islands MSM-PD was evaluated by dark and photo current-voltage (I-V) measurements at room temperature (RT). It was found that the device with island and wetting layer significantly enhance the current gain (ratio of photo current to dark current) of the device.

Effects of thermal treatment on the MgxZn1−xO films and fabrication of visible-blind and solar-blind ultraviolet photodetectors

International Nuclear Information System (INIS)

Tian, Chunguang; Jiang, Dayong; Tan, Zhendong; Duan, Qian; Liu, Rusheng; Sun, Long; Qin, Jieming; Hou, Jianhua; Gao, Shang; Liang, Qingcheng; Zhao, Jianxun

2014-01-01

Highlights: • Single-phase wurtzite/cubic Mg x Zn 1−x O films were grown by RF magnetron sputtering technique. • We focus on the red-shift caused by annealing the Mg x Zn 1−x O films. • MSM-structured visible-blind and solar-blind UV photodetectors were fabricated. - Abstract: A series of single-phase Mg x Zn 1−x O films with different Mg contents were prepared on quartz substrates by RF magnetron sputtering technique using different MgZnO targets, and annealed under the atmospheric environment. The absorption edges of Mg x Zn 1−x O films can cover the whole near ultraviolet and even the whole solar-blind spectra range, and the solar-blind wurtzite/cubic Mg x Zn 1−x O films have been realized successfully by the same method. In addition, the absorption edges of annealed films shift to a long wavelength, which is caused by the diffusion of Zn atoms gathering at the surface during the thermal treatment process. Finally, the truly solar-blind metal-semiconductor-metal structured photodetectors based on wurtzite Mg 0.445 Zn 0.555 O and cubic Mg 0.728 Zn 0.272 O films were fabricated. The corresponding peak responsivities are 17 mA/W at 275 nm and 0.53 mA/W at 250 nm under a 120 V bias, respectively

Indirect X-ray Detectors Based on Inkjet-Printed Photodetectors with a Screen-Printed Scintillator Layer.

Science.gov (United States)

Oliveira, Juliana; Correia, Vitor; Sowade, Enrico; Etxebarria, Ikerne; Rodriguez, Raul D; Mitra, Kalyan Y; Baumann, Reinhard R; Lanceros-Mendez, Senentxu

2018-04-18

Organic photodetectors (PDs) based on printing technologies will allow to expand the current field of PD applications toward large-area and flexible applications in areas such as medical imaging, security, and quality control, among others. Inkjet printing is a powerful digital tool for the deposition of smart and functional materials on various substrates, allowing the development of electronic devices such as PDs on various substrates. In this work, inkjet-printed PD arrays, based on the organic thin-film transistor architecture, have been developed and applied for the indirect detection of X-ray radiation using a scintillator ink as an X-ray absorber. The >90% increase of the photocurrent of the PDs under X-ray radiation, from about 53 nA without the scintillator film to about 102 nA with the scintillator located on top of the PD, proves the suitability of the developed printed device for X-ray detection applications.

Highly Efficient Organic UV Photodetectors Based on Polyfluorene and Naphthalenediimide Blends: Effect of Thermal Annealing

Directory of Open Access Journals (Sweden)

Gorkem Memisoglu

2012-01-01

Full Text Available A solution-processed organic ultraviolet photodetector (UV-PD is introduced. The active layer of the UV-PD consists of poly(9,9-dioctyl fluorenyl-2,7–yleneethynylene (PFE and N,N′-bis-n-butyl-1,4,5,8- naphthalenediimide (BNDI with a weight ratio of 3 : 1 in chloroform. The effect of thermal annealing on the device properties was investigated from room temperature to 80∘C. The full device structure of ITO/PEDOT:PSS/PFE:BNDI (3 : 1/Al gave responsivity of 410 mA/W at −4 V under 1 mW/cm2 UV light at 368 nm when 60∘C of annealing temperature was used during its preparation. The devices that were annealed over the crystallization temperature of PFE showed a charge transfer resistance increase and a mobility decrease.

Advances in near-infrared measurements

CERN Document Server

Patonay, Gabor

1991-01-01

Advances in Near-Infrared Measurements, Volume 1 provides an overview of near-infrared spectroscopy. The book is comprised of six chapters that tackle various areas of near-infrared measurement. Chapter 1 discusses remote monitoring techniques in near-infrared spectroscopy with an emphasis on fiber optics. Chapter 2 covers the applications of fibers using Raman techniques, and Chapter 3 tackles the difficulties associated with near-infrared data analysis. The subsequent chapters present examples of the capabilities of near-infrared spectroscopy from various research groups. The text wi

Infrared

Science.gov (United States)

Vollmer, M.

2013-11-01

'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

Photosensitive graphene transistors.

Science.gov (United States)

Li, Jinhua; Niu, Liyong; Zheng, Zijian; Yan, Feng

2014-08-20

High performance photodetectors play important roles in the development of innovative technologies in many fields, including medicine, display and imaging, military, optical communication, environment monitoring, security check, scientific research and industrial processing control. Graphene, the most fascinating two-dimensional material, has demonstrated promising applications in various types of photodetectors from terahertz to ultraviolet, due to its ultrahigh carrier mobility and light absorption in broad wavelength range. Graphene field effect transistors are recognized as a type of excellent transducers for photodetection thanks to the inherent amplification function of the transistors, the feasibility of miniaturization and the unique properties of graphene. In this review, we will introduce the applications of graphene transistors as photodetectors in different wavelength ranges including terahertz, infrared, visible, and ultraviolet, focusing on the device design, physics and photosensitive performance. Since the device properties are closely related to the quality of graphene, the devices based on graphene prepared with different methods will be addressed separately with a view to demonstrating more clearly their advantages and shortcomings in practical applications. It is expected that highly sensitive photodetectors based on graphene transistors will find important applications in many emerging areas especially flexible, wearable, printable or transparent electronics and high frequency communications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Infrared up-conversion microscope

DEFF Research Database (Denmark)

2014-01-01

There is presented an up-conversion infrared microscope (110) arranged for imaging an associated object (130), wherein the up-conversion infrared microscope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein an objective optical...

Infrared up-conversion telescope

DEFF Research Database (Denmark)

2014-01-01

There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...

A Micromachined Infrared Senor for an Infrared Focal Plane Array

Directory of Open Access Journals (Sweden)

Seong M. Cho

2008-04-01

Full Text Available A micromachined infrared sensor for an infrared focal plane array has been designed and fabricated. Amorphous silicon was used as a sensing material, and silicon nitride was used as a membrane material. To get a good absorption in infrared range, the sensor structure was designed as a l/4 cavity structure. A Ni-Cr film was selected as an electrode material and mixed etching scheme was applied in the patterning process of the Ni-Cr electrode. All the processes were made in 0.5 μm iMEMS fabricated in the Electronics and Telecommunication Research Institute (ETRI. The processed MEMS sensor had a small membrane deflection less than 0.15 μm. This small deflection can be attributed to the rigorous balancing of the stresses of individual layers. The efficiency of infrared absorption was more than 75% in the wavelength range of 8 ~ 14 μm. The processed infrared sensor showed high responsivity of ~230 kV/W at 1.0V bias and 2 Hz operation condition. The time constant of the sensor was 8.6 msec, which means that the sensor is suitable to be operated in 30 Hz frame rate.

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.

Infrared Sky Surveys

Science.gov (United States)

Price, Stephan D.

2009-02-01

A retrospective is given on infrared sky surveys from Thomas Edison’s proposal in the late 1870s to IRAS, the first sensitive mid- to far-infrared all-sky survey, and the mid-1990s experiments that filled in the IRAS deficiencies. The emerging technology for space-based surveys is highlighted, as is the prominent role the US Defense Department, particularly the Air Force, played in developing and applying detector and cryogenic sensor advances to early mid-infrared probe-rocket and satellite-based surveys. This technology was transitioned to the infrared astronomical community in relatively short order and was essential to the success of IRAS, COBE and ISO. Mention is made of several of the little known early observational programs that were superseded by more successful efforts.

MSM optical detector on the basis of II-type ZnSe/ZnTe superlattice

Energy Technology Data Exchange (ETDEWEB)

Kuznetzov, P. I., E-mail: pik218@ire216.msk.su; Averin, S. V., E-mail: sva278@ire216.msk.su; Zhitov, V. A.; Zakharov, L. Yu.; Kotov, V. M. [Russian Academy of Sciences, Kotel’nikov Institute of Radioengineering and Electronics (Fryazino Branch) (Russian Federation)

2017-02-15

On the basis of a type-II ZnSe/ZnTe superlattice, a MSM (metal—semiconductor–metal) photodetector is fabricated and investigated. The detector features low dark currents and a high sensitivity. The spectral characteristic of the detector provides the possibility of the selective detection of three separate spectral portions of visible and near-infrared radiation.

Measuring the photodetector frequency response for ultrasonic applications by a heterodyne system with difference- frequency servo control.

Science.gov (United States)

Koch, Christian

2010-05-01

A technique for the calibration of photodiodes in ultrasonic measurement systems using standard and cost-effective optical and electronic components is presented. A heterodyne system was realized using two commercially available distributed feedback lasers, and the required frequency stability and resolution were ensured by a difference-frequency servo control scheme. The frequency-sensitive element generating the error signal for the servo loop comprised a delay-line discriminator constructed from electronic elements. Measurements were carried out at up to 450 MHz, and the uncertainties of about 5% (k = 2) can be further reduced by improved radio frequency power measurement without losing the feature of using only simple elements. The technique initially dedicated to the determination of the frequency response of photodetectors applied in ultrasonic applications can be transferred to other application fields of optical measurements.

Broadband integrated mid infrared light sources as enabling technology for point of care mid-infrared spectroscopy

Science.gov (United States)

2017-08-20

AFRL-AFOSR-JP-TR-2017-0061 Broadband integrated mid-infrared light sources as enabling technology for point-of-care mid- infrared spectroscopy Alex...mid-infrared light sources as enabling technology for point-of-care mid-infrared spectroscopy 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-16-1-4037...Broadband integrated mid-infrared light sources as enabling technology for point-of-care mid- infrared spectroscopy ” Date: 16th August 2017 Name

Data compressive paradigm for multispectral sensing using tunable DWELL mid-infrared detectors.

Science.gov (United States)

Jang, Woo-Yong; Hayat, Majeed M; Godoy, Sebastián E; Bender, Steven C; Zarkesh-Ha, Payman; Krishna, Sanjay

2011-09-26

While quantum dots-in-a-well (DWELL) infrared photodetectors have the feature that their spectral responses can be shifted continuously by varying the applied bias, the width of the spectral response at any applied bias is not sufficiently narrow for use in multispectral sensing without the aid of spectral filters. To achieve higher spectral resolutions without using physical spectral filters, algorithms have been developed for post-processing the DWELL's bias-dependent photocurrents resulting from probing an object of interest repeatedly over a wide range of applied biases. At the heart of these algorithms is the ability to approximate an arbitrary spectral filter, which we desire the DWELL-algorithm combination to mimic, by forming a weighted superposition of the DWELL's non-orthogonal spectral responses over a range of applied biases. However, these algorithms assume availability of abundant DWELL data over a large number of applied biases (>30), leading to large overall acquisition times in proportion with the number of biases. This paper reports a new multispectral sensing algorithm to substantially compress the number of necessary bias values subject to a prescribed performance level across multiple sensing applications. The algorithm identifies a minimal set of biases to be used in sensing only the relevant spectral information for remote-sensing applications of interest. Experimental results on target spectrometry and classification demonstrate a reduction in the number of required biases by a factor of 7 (e.g., from 30 to 4). The tradeoff between performance and bias compression is thoroughly investigated. © 2011 Optical Society of America

3.2 Gigabit-per-second Visible Light Communication Link with InGaN/GaN MQW Micro-photodetector

KAUST Repository

Ho, Kang Ting

2018-01-29

This paper presents the first demonstration of InGaN multiple quantum well (MQW) based micro-photodetectors (µPD) used as the optical receiver in orthogonal frequency-division multiplexing (OFDM) modulated visible communication system (VLC). The 80-µm diameter µPD exhibits a wavelength-selective responsivity in the near-UV to violet regime (374 nm - 408 nm) under a low reverse bias of −3 V. The modulation scheme of 16-quadrature amplitude modulation (16-QAM) OFDM enables the use of frequency response beyond −3 dB cutoff bandwidth of µPD. A record high data rate of 3.2 Gigabit per second (Gpbs) was achieved as a result, which provides the proof-of-concept verification of a viable high speed VLC link.

Application of Metal-Semiconductor-Metal (MSM) Photodetectors for Transverse and Longitudinal Intra-Bunch Beam Diagnostics

CERN Document Server

Steinhagen, R J; Boland, M J; Lucas, T G; Rassool, R P

2013-01-01

The performance reach of modern accelerators is often governed by the ability to reliably measure and control the beam stability. In high-brightness lepton and high-energy hadron accelerators, the use of optical diagnostic techniques is becoming more widespread as the required bandwidth, resolution and high RF beam power level involved limit the use of traditional electro-magnetic RF pick-up based methods. This contribution discusses the use of fibre-coupled ultra-fast Metal-Semiconductor-Metal Photodetectors (MSM-PD) as an alternative, dependablemeans to measure signals derived from electro-optical and synchrotron-light based diagnostics systems. It describes the beam studies performed at CERN’s CLIC Test Facility (CTF3) and the Australian Synchrotron to assess the feasibility of this technology as a robust, wide-band and sensitive technique for measuring transverse intra-bunch and bunch-by-bunch beam oscillations, longitudinal beam profiles, un-bunched beam population and beam-halo profiles. The amplifica...

Exploring the effective photon management by InP nanoparticles: Broadband light absorption enhancement of InP/In0.53Ga0.47As/InP thin-film photodetectors

International Nuclear Information System (INIS)

Fu, Dong; Zhu, Xi; Li, Jian; Xu, Yun; Song, Guofeng; Wei, Xin; Liu, Jietao

2015-01-01

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

Infrared and infrared emission spectroscopic study of typical Chinese kaolinite and halloysite.

Science.gov (United States)

Cheng, Hongfei; Frost, Ray L; Yang, Jing; Liu, Qinfu; He, Junkai

2010-12-01

The structure and thermal stability between typical Chinese kaolinite and halloysite were analysed by X-ray diffraction (XRD), infrared spectroscopy, infrared emission spectroscopy (IES) and Raman spectroscopy. Infrared emission spectroscopy over the temperature range of 300-700°C has been used to characterise the thermal decomposition of both kaolinite and halloysite. Halloysite is characterised by two bands in the water bending region at 1629 and 1648 cm(-1), attributed to structural water and coordinated water in the interlayer. Well defined hydroxyl stretching bands at around 3695, 3679, 3652 and 3625 cm(-1) are observed for both kaolinite and halloysite. The 550°C infrared emission spectrum of halloysite is similar to that of kaolinite in 650-1350 cm(-1) spectral region. The infrared emission spectra of halloysite were found to be considerably different to that of kaolinite at lower temperatures. These differences are attributed to the fundamental difference in the structure of the two minerals. Copyright © 2010 Elsevier B.V. All rights reserved.

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity

KAUST Repository

Leung, Siu

2018-01-10

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3 NH3 PBI3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH3 NH3 PBI3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 1013 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW-1 cm-2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications.

Large bandgap reduced graphene oxide (rGO) based n-p + heterojunction photodetector with improved NIR performance

Science.gov (United States)

Singh, Manjri; Kumar, Gaurav; Prakash, Nisha; Khanna, Suraj P.; Pal, Prabir; Singh, Surinder P.

2018-04-01

Integration of two-dimensional reduced graphene oxide (rGO) with conventional Si semiconductor offers novel strategies for realizing broadband photodiode with enhanced device performance. In this quest, we have synthesized large bandgap rGO and fabricated metal-free broadband (300–1100 nm) back-to-back connected np-pn hybrid photodetector utilizing drop casted n-rGO/p +-Si heterojunctions with high performance in NIR region (830 nm). With controlled illumination, the device exhibited a peak responsivity of 16.7 A W‑1 and peak detectivity of 2.56 × 1012 Jones under 830 nm illumination (11 μW cm‑2) at 1 V applied bias with fast response (∼460 μs) and recovery time (∼446 μs). The fabricated device demonstrated excellent repeatability, durability and photoswitching behavior with high external quantum efficiency (∼2.5 × 103%), along with ultrasensitive behavior at low light conditions.

Infrared Astronomy and Star Formation

International Nuclear Information System (INIS)

Evans, N.J.

1985-01-01

Infrared astronomy is a natural tool to use in studying star formation because infrared light penetrates the surrounding dust and because protostars are expected to emit infrared light. Infrared mapping and photometry have revealed many compact sources, often embedded in more extensive warm dust associated with a molecular cloud core. More detailed study of these objects is now beginning, and traditional interpretations are being questioned. Some compact sources are now thought to be density enhancements which are not self-luminous. Infrared excesses around young stars may not always be caused by circumstellar dust; speckle measurements have shown that at least some of the excess toward T Tauri is caused by an infrared companion. Spectroscopic studies of the dense, star-forming cores and of the compact objects themselves have uncovered a wealth of new phenomena, including the widespread occurence of energetic outflows. New discoveries with IRAS and with other planned infrared telescopes will continue to advance this field. (author)

Infrared microscope inspection apparatus

Science.gov (United States)

Forman, Steven E.; Caunt, James W.

1985-02-26

Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface.

History of infrared detectors

Science.gov (United States)

Rogalski, A.

2012-09-01

This paper overviews the history of infrared detector materials starting with Herschel's experiment with thermometer on February 11th, 1800. Infrared detectors are in general used to detect, image, and measure patterns of the thermal heat radiation which all objects emit. At the beginning, their development was connected with thermal detectors, such as thermocouples and bolometers, which are still used today and which are generally sensitive to all infrared wavelengths and operate at room temperature. The second kind of detectors, called the photon detectors, was mainly developed during the 20th Century to improve sensitivity and response time. These detectors have been extensively developed since the 1940's. Lead sulphide (PbS) was the first practical IR detector with sensitivity to infrared wavelengths up to ˜3 μm. After World War II infrared detector technology development was and continues to be primarily driven by military applications. Discovery of variable band gap HgCdTe ternary alloy by Lawson and co-workers in 1959 opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design. Many of these advances were transferred to IR astronomy from Departments of Defence research. Later on civilian applications of infrared technology are frequently called "dual-use technology applications." One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies, as well as the noticeable price decrease in these high cost technologies. In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays (FPAs). Development in FPA technology has revolutionized infrared imaging. Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.

High Quantum Efficiency Back-Illuminated AlGaN-Based Solar-Blind Ultraviolet p—i—n Photodetectors

International Nuclear Information System (INIS)

Wang Guo-Sheng; Lu Hai; Xie Feng; Chen Dun-Jun; Ren Fang-Fang; Zhang Rong; Zheng You-Dou

2012-01-01

AlGaN-based back-illuminated solar-blind ultraviolet (UV) p—i—n photodetectors (PDs) with high quantum efficiency are fabricated on sapphire substrates. To improve the overall performance of the PD, a series of structural design considerations and growth procedures are implemented in the epitaxy process. A distinct wavelength-selective photo-response peak of the PD is obtained in the solar-blind region. When operating in photovoltaic mode, the PD exhibits a solar-blind/UV rejection ratio of up to 4 orders of magnitude and a peak responsivity of ∼113.5 mA/W at 270 nm, which corresponds to an external quantum efficiency of ∼52%. Under a reverse bias of −5 V, the PD shows a low dark current of ∼1.8 pA and an enhanced peak quantum efficiency of ∼64%. The thermal noise limited detectivity is estimated to be ∼ 3.3 × 10 13 cm·Hz 1/2 W −1

The photonic device for integrated evaluation of collateral circulation of lower extremities in patients with local hypertensive-ischemic pain syndrome

Science.gov (United States)

Pavlov, Volodymyr S.; Bezsmernyi, Yurii O.; Zlepko, Sergey M.; Bezsmertna, Halyna V.

2017-08-01

The given paper analyzes principles of interaction and analysis of the reflected optical radiation from biotissue in the process of assessment of regional hemodynamics state in patients with local hypertensive- ischemic pain syndrome of amputation stumps of lower extremities, applying the method of photoplethysmography. The purpose is the evaluation of Laser photoplethysmography (LPPG) diagnostic value in examination of patients with chronic ischemia of lower extremities. Photonic device is developed to determine the level of the peripheral blood circulation, which determines the basic parameters of peripheral blood circulation and saturation level. Device consists of two sensors: infrared sensor, which contains the infrared laser radiation source and photodetector, and red sensor, which contains the red radiation source and photodetector. LPPG method allows to determined pulsatility of blood flow in different areas of the foot and lower leg, the degree of compensation and conservation perspectives limb. Surgical treatment of local hypertensive -ischemic pain syndrome of amputation stumps of lower extremities by means of semiclosed fasciotomy in combination with revasculating osteotrepanation enabled to improve considerably regional hemodynamics in the tissues of the stump and decrease pain and hypostatic disorders.

Feldspar, Infrared Stimulated Luminescence

DEFF Research Database (Denmark)

Jain, Mayank

2014-01-01

This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

Infrared emission from supernova condensates

International Nuclear Information System (INIS)

Dwek, E.; Werner, M.W.

1981-01-01

We examine the possibility of detecting grains formed in supernovae by observations of their emission in the infrared. The basic processes determining the temperature and infrared radiation of grains in supernovae environments are analyzed, and the results are used to estimate the infrared emission from the highly metal enriched ''fast moving knots'' in Cas A. The predicted fluxes lie within the reach of current ground-based facilities at 10 μm, and their emission should be detectable throughout the infrared band with cryogenic space telescopes

CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector

KAUST Repository

Maculan, Giacomo

2015-09-02

Single crystals of hybrid perovskites have shown remarkably improved physical properties compared to their polycrystalline film counterparts, underscoring their importance in the further development of advanced semiconductor devices. Here we present a new method of sizeable CH3NH3PbCl3 single crystal growth based on retrograde solubility behavior of hybrid perovskites. We show, for the first time, the energy band structure, charge-carrier recombination and transport properties of single crystal CH3NH3PbCl3. The chloride-based perovskite crystals exhibit trap-state density, charge carriers concentration, mobility and diffusion length comparable with the best quality crystals of methylammonium lead iodide or bromide perovskites reported so far. The high quality of the crystal along with its suitable optical bandgap enabled us to design and build an efficient visible-blind UV-photodetector, demonstrating the potential of this material to be employed in optoelectronic applications.

Direct exchange between silicon nanocrystals and tunnel oxide traps under illumination on single electron photodetector

Energy Technology Data Exchange (ETDEWEB)

Chatbouri, S., E-mail: Samir.chatbouri@yahoo.com; Troudi, M.; Sghaier, N.; Kalboussi, A. [Avenue de I’environnement, Université de Monastir, Laboratoire de Micro électronique et Instrumentation (LR13ES12), Faculté des Sciences de Monastir (Tunisia); Aimez, V. [Université de Sherbrooke, Laboratoire Nanotechnologies et Nanosystémes (UMI-LN2 3463), Université de Sherbrooke—CNRS—INSA de Lyon-ECL-UJF-CPE Lyon, Institut Interdisciplinaire d’Innovation Technologique (Canada); Drouin, D. [Avenue de I’environnement, Université de Monastir, Laboratoire de Micro électronique et Instrumentation (LR13ES12), Faculté des Sciences de Monastir (Tunisia); Souifi, A. [Institut des Nanotechnologies de Lyon—site INSA de Lyon, UMR CNRS 5270 (France)

2016-09-15

In this paper we present the trapping of photogenerated charge carriers for 300 s resulted by their direct exchange under illumination between a few silicon nanocrystals (ncs-Si) embedded in an oxide tunnel layer (SiO{sub x} = 1.5) and the tunnel oxide traps levels for a single electron photodetector (photo-SET or nanopixel). At first place, the presence of a photocurrent limited in the inversion zone under illumination in the I–V curves confirms the creation of a pair electron/hole (e–h) at high energy. This photogenerated charge carriers can be trapped in the oxide. Using the capacitance-voltage under illumination (the photo-CV measurements) we show a hysteresis chargement limited in the inversion area, indicating that the photo-generated charge carriers are stored at traps levels at the interface and within ncs-Si. The direct exchange of the photogenerated charge carriers between the interface traps levels and the ncs-Si contributed on the photomemory effect for 300 s for our nanopixel at room temperature.

Infrared emission and extragalactic starbursts

International Nuclear Information System (INIS)

Telesco, C.M.

1985-01-01

The paper examines the belief that recent star formation plays a significant role in determining many of the infrared properties of galaxies. Pertinent types of infrared observations and the infrared properties of starbursts are briefly summarized. Recently developed models which describe the evolution of starbursts are also considered. (U.K.)

Nonlinear optics in germanium mid-infrared fiber material: Detuning oscillations in femtosecond mid-infrared spectroscopy

Directory of Open Access Journals (Sweden)

M. Ordu

2017-09-01

Full Text Available Germanium optical fibers hold great promise in extending semiconductor photonics into the fundamentally important mid-infrared region of the electromagnetic spectrum. The demonstration of nonlinear response in fabricated Ge fiber samples is a key step in the development of mid-infrared fiber materials. Here we report the observation of detuning oscillations in a germanium fiber in the mid-infrared region using femtosecond dispersed pump-probe spectroscopy. Detuning oscillations are observed in the frequency-resolved response when mid-infrared pump and probe pulses are overlapped in a fiber segment. The oscillations arise from the nonlinear frequency resolved nonlinear (χ(3 response in the germanium semiconductor. Our work represents the first observation of coherent oscillations in the emerging field of germanium mid-infrared fiber optics.

A novel high-performance self-powered ultraviolet photodetector: Concept, analytical modeling and analysis

Science.gov (United States)

Ferhati, H.; Djeffal, F.

2017-12-01

In this paper, a new MSM-UV-photodetector (PD) based on dual wide band-gap material (DM) engineering aspect is proposed to achieve high-performance self-powered device. Comprehensive analytical models for the proposed sensor photocurrent and the device properties are developed incorporating the impact of DM aspect on the device photoelectrical behavior. The obtained results are validated with the numerical data using commercial TCAD software. Our investigation demonstrates that the adopted design amendment modulates the electric field in the device, which provides the possibility to drive appropriate photo-generated carriers without an external applied voltage. This phenomenon suggests achieving the dual role of effective carriers' separation and an efficient reduce of the dark current. Moreover, a new hybrid approach based on analytical modeling and Particle Swarm Optimization (PSO) is proposed to achieve improved photoelectric behavior at zero bias that can ensure favorable self-powered MSM-based UV-PD. It is found that the proposed design methodology has succeeded in identifying the optimized design that offers a self-powered device with high-responsivity (98 mA/W) and superior ION/IOFF ratio (480 dB). These results make the optimized MSM-UV-DM-PD suitable for providing low cost self-powered devices for high-performance optical communication and monitoring applications.

A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity.

Science.gov (United States)

Leung, Siu-Fung; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K S; Alshareef, Husam N; Wang, Zhong Lin; He, Jr-Hau

2018-02-01

Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH 3 NH 3 PBI 3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH 3 NH 3 PBI 3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 10 13 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW -1 cm -2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design of an omnidirectional single-point photodetector for large-scale spatial coordinate measurement

Science.gov (United States)

Xie, Hongbo; Mao, Chensheng; Ren, Yongjie; Zhu, Jigui; Wang, Chao; Yang, Lei

2017-10-01

In high precision and large-scale coordinate measurement, one commonly used approach to determine the coordinate of a target point is utilizing the spatial trigonometric relationships between multiple laser transmitter stations and the target point. A light receiving device at the target point is the key element in large-scale coordinate measurement systems. To ensure high-resolution and highly sensitive spatial coordinate measurement, a high-performance and miniaturized omnidirectional single-point photodetector (OSPD) is greatly desired. We report one design of OSPD using an aspheric lens, which achieves an enhanced reception angle of -5 deg to 45 deg in vertical and 360 deg in horizontal. As the heart of our OSPD, the aspheric lens is designed in a geometric model and optimized by LightTools Software, which enables the reflection of a wide-angle incident light beam into the single-point photodiode. The performance of home-made OSPD is characterized with working distances from 1 to 13 m and further analyzed utilizing developed a geometric model. The experimental and analytic results verify that our device is highly suitable for large-scale coordinate metrology. The developed device also holds great potential in various applications such as omnidirectional vision sensor, indoor global positioning system, and optical wireless communication systems.

Infrared emission from protostars

International Nuclear Information System (INIS)

Adams, F.C.; Shu, F.H.

1985-01-01

The emergent spectral energy distribution at infrared to radio wavelengths is calculated for the simplest theoretical construct of a low-mass protostar. It is shown that the emergent spectrum in the infrared is insensitive to the details assumed for the temperature profile as long as allowance is made for a transition from optically thick to optically thin conditions and luminosity conservation isenforced at the inner and outer shells. The radiation in the far infrared and submillimeter wavelengths depends on the exact assumptions made for grain opacities at low frequencies. An atlas of emergent spectral energy distributions is presented for a grid of values of the instantaneous mass of the protostar and the mass infall rate. The attenuated contribution of the accretion shock to the near-infrared radiation is considered. 50 references

Germanium blocked impurity band far infrared detectors

International Nuclear Information System (INIS)

Rossington, C.S.

1988-04-01

The infrared portion of the electromagnetic spectrum has been of interest to scientist since the eighteenth century when Sir William Herschel discovered the infrared as he measured temperatures in the sun's spectrum and found that there was energy beyond the red. In the late nineteenth century, Thomas Edison established himself as the first infrared astronomer to look beyond the solar system when he observed the star Arcturus in the infrared. Significant advances in infrared technology and physics, long since Edison's time, have resulted in many scientific developments, such as the Infrared Astronomy Satellite (IRAS) which was launched in 1983, semiconductor infrared detectors for materials characterization, military equipment such as night-vision goggles and infrared surveillance equipment. It is now planned that cooled semiconductor infrared detectors will play a major role in the ''Star Wars'' nuclear defense scheme proposed by the Reagan administration

Trap assisted charge multiplication enhanced photoresponse of Li-P codoped p-ZnO/n-Si heterojunction ultraviolet photodetectors

Science.gov (United States)

Sharma, Pankaj; Bhardwaj, Ritesh; Kumar, Amitesh; Mukherjee, Shaibal

2018-01-01

In this work, we report a high-performance p-ZnO/n-Si heterojunction-based ultraviolet (UV) photodetector fabricated by dual ion beam sputter deposition. The lithium-phosphorus (Li-P) codoping route was used to realize low resistive and stable p-type ZnO. The current-voltage characteristics of p-ZnO/n-Si heterojunction photodiode showed good rectifying behavior with a rectification ratio of 170 at  ±3 V. The spectral response measurements of the photodiode showed excellent responsivity with a peak observed around ~325 nm and cutoff wavelength around 370 nm. The maximum responsivity achieved was 2.6 A W-1 at an applied reverse bias of  -6 V. The external quantum efficiency determined was of the order of ~1000% which is attributed to the trap assisted multiplication of charge carriers.

Towards the mid-infrared optical biopsy

DEFF Research Database (Denmark)

Seddon, Angela B.; Benson, Trevor M.; Sujecki, Slawomir

2016-01-01

We are establishing a new paradigm in mid-infrared molecular sensing, mapping and imaging to open up the mid-infrared spectral region for in vivo (i.e. in person) medical diagnostics and surgery. Thus, we are working towards the mid-infrared optical biopsy ('opsy' look at, bio the biology) in situ...... in the body for real-time diagnosis. This new paradigm will be enabled through focused development of devices and systems which are robust, functionally designed, safe, compact and cost effective and are based on active and passive mid-infrared optical fibers. In particular, this will enable early diagnosis...... of a bright mid-infrared wideband source in a portable package as a first step for medical fiber-based systems operating in the mid-infrared. Moreover, mid-infrared molecular mapping and imaging is potentially a disruptive technology to give improved monitoring of the environment, energy efficiency, security...

Infrared nanoantenna apparatus and method for the manufacture thereof

Science.gov (United States)

Peters, David W.; Davids, Paul; Leonhardt, Darin; Kim, Jin K.; Wendt, Joel R.; Klem, John F.

2014-06-10

An exemplary embodiment of the present invention is a photodetector comprising a semiconductor body, a periodically patterned metal nanoantenna disposed on a surface of the semiconductor body, and at least one electrode separate from the nanoantenna. The semiconductor body comprises an active layer in sufficient proximity to the nanoantenna for plasmonic coupling thereto. The nanoantenna is dimensioned to absorb electromagnetic radiation in at least some wavelengths not more than 12 .mu.m that are effective for plasmonic coupling into the active layer. The electrode is part of an electrode arrangement for obtaining a photovoltage or photocurrent in operation under appropriate stimulation.

Infrared Fe II lines in Eta Carinae and a possible interpretation of infrared excesses

International Nuclear Information System (INIS)

Thackeray, A.D.

1978-01-01

The identification of very strong emission lines in the near infrared spectrum of Eta Carinae with newly recognised high-level transitions of Fe II raises the possibility that the infrared excesses of hot emission-line stars may be due to dielectronic recombination of Fe II. Johansson's Fe II lines also need to be considered in the interpretation of the infrared spectra of supernovae. (author)