- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
AIP Conference Proceedings [AIP Publishing SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 - Erode, India (21–22 November 2019)] SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 - Modeling of optical characteristics of near-infrared photodetectors on the basis of InAs/GaAs heterointerfaces
摘要： A mathematical model for simulation of optical and functional characteristics of InAs/GaAs heterointerfaces with one layer of InAs quantum dots has been developed. The presence of the peak of the main optical transitions in quantum dots of 1.2 eV (modeling) and 1.12 eV (experimental) is demonstrated. The experimental photoluminescence peak has a greater width (0.13 eV) at half the maximum radiation of the main transitions in quantum dots compared to the simulated one (0.06 eV). A red shift of the experimental peak by approximately 65 meV is observed, which indicates the presence of a size variance of quantum dots in the real heterointerface. The modeled distribution of the dark current-voltage characteristic at 90 K and zero shift reveals the value of the dark current density of 10-7 A/cm2, which is an order of magnitude less than the measurement results (10-6 A/cm2). The difference in the pattern of dependence distribution at negative and positive bias associated with the presence of quantum dots of larger size is observed.
关键词： quantum dots,InAs/GaAs heterointerfaces,photoluminescence,dark current-voltage characteristics
更新于2025-09-12 10:27:22
-
Effect of Evanescent Waves on the Dark Current of Thermophotovoltaic Cells
摘要： The output power of thermophotovoltaic (TPV) cells may be greatly increased when the gap between the emitter and cell is reduced to sub-micron distances (near-field regime), at which photon tunneling due to evanescent waves becomes important. Accurate modeling of TPV cells in these conditions is crucial for the design and optimization of near-field TPV systems. The conventional or standard modeling method uses the summation of the dark current and the short-circuit current, while the direct method applies the photon chemical potential. It has been shown that the two methods are linked through a modification of the direct method using Wien’s approximation. By contrasting different modeling approaches, we quantitatively analyze the effects of evanescent waves on the TPV cell performance parameters, especially the dark current, for different emitter and cell materials in the near-field regime. Our results show that the saturation current by radiative recombination is strongly affected by evanescent waves and the bandgap energy. The current-voltage characteristics calculated by different modeling methods are displayed to demonstrate that a constant saturation current typically used in the standard method could cause substantial error in the near-field regime. For a TPV system with an emitter operating at relatively low temperatures, we show that it is necessary to include the photon chemical potential in the computation of the net radiative heat transfer between the emitter and receiver.
关键词： evanescent waves,Dark current,near-field thermophotovoltaic,diode
更新于2025-09-11 14:15:04
-
Ultra-Robust Deep-UV Photovoltaic Detector Based on Graphene/(AlGa) <sub/>2</sub> O <sub/>3</sub> /GaN with High-Performance in Temperature Fluctuations
摘要： A strategy of adopting Ga2O3 alloyed with Al element to reduce the oxygen vacancy defect density and to enhance the interface barrier height of Ga2O3 heterojunction is proposed to fabricate deep-UV photovoltaic detectors with high thermal stability, high photoresponsivity and fast response speed. Here, a graphene/(AlGa)2O3/GaN device with a photoresponsivity of ~20 mA/W, a rise time of ~2 μs and a decay time of ~10 ms is presented at 0 V bias. At the working temperature of 453 K, the device still exhibits a photo-to-dark current ratio (PDCR) of ~1.8×103, which is 1-2 orders of magnitude higher than that of reported high temperature deep-UV film detectors. By comparing the formation energy of oxygen vacancy defects and the interface barrier height of heterojunction at different temperatures in graphene/Ga2O3/GaN and graphene/(AlGa)2O3/GaN systems respectively, the strategy of synthesizing (AlGa)2O3 ternary composite alloy is proved reliable for fabricating high performance deep-UV photovoltaic detectors. The method proposed in this paper can provide reference for the preparation of deep-UV photovoltaic detectors with high photoresponsivity and thermal stability in the future.
关键词： deep-UV,high temperature,photovoltaic,(AlGa)2O3,high photo-to-dark current ratio
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - Al <sub/>x</sub> In <sub/>1-x</sub> As <sub/>y</sub> Sb <sub/>1-y</sub> Separate Absorption, Charge, and Multiplication Avalanche Photodiodes for 2-μm Detection
摘要： We report separate absorption, charge, and multiplication (SACM) avalanche photodiodes (APDs) in the AlxIn1-xAsySb1-y material system for 2-μm detection. Gain, dark current, and low excess noise are demonstrated.
关键词： noise figure,optoelectronic devices,photodetectors,Avalanche photodiodes,dark current
更新于2025-09-11 14:15:04
-
Analysis of dark current generated by long-wave infrared HgCdTe photodiodes with different implantation shapes
摘要： Resistance-voltage curves of B+-implanted n-on-p Hg1-xCdxTe long-wavelength infrared photodiodes with different implantation unit shapes were measured for temperatures in the 20–140 K range. The response spectrum of the device was measured, and the response cutoff wavelength was 11.45 μm. By fitting the experimental data, R0A at different temperatures and the dark current at different bias voltages of the two long-wavelength diodes were calculated theoretically. The results demonstrate that the response spectrum of the device is affected by the implantation shape. The temperature transformation point of the dominant dark current was 40 K, and correlations between some parameters were also demonstrated.
关键词： dark current,long-wave infrared,HgCdTe,photosensors
更新于2025-09-11 14:15:04
-
[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Model Calibration of InGaAs/InP p-I-n Test Structures
摘要： Numerical calibration of InGaAs/InP double-heterostructure p-I-n junctions is performed at room temperature using guarded test structures of various areas and investigating the contributions from minority carrier diffusion, depletion region generation and finally perimeter (shunt) leakage. The perimeter leakage is determined to be 0.5 pA/cm, whereas the depletion region contributes 2.2 nA/cm2; the bulk diffusion contribution is excluded via the guard ring but can be computed analytically to be 2.0 nA/cm2. Reproducing the experimental test structures within the numerical modeling environment accurately reproduces the data based on calibrating the diffusion length and SRH lifetime.
关键词： dark current,III-V semiconductors,diffusion length,perimeter leakage,recombination
更新于2025-09-11 14:15:04
-
Graphene interdigital electrodes for improving sensitivity in Ga2O3:Zn deep-ultraviolet photoconductive detector
摘要： Graphene (Gr) has been widely used as a transparent electrode material for photodetectors due to its high conductivity and high transmittance, in recent years. However, the currently low-efficiency manipulation of Gr has hindered the arraying and practical use of such detectors. We invented a multi-step method of accurately tailoring graphene into interdigital electrodes, for fabricating a sensitive, stable deep-ultraviolet photodetector based on Zn-doped Ga2O3 films. The fabricated photodetector exhibits a series of excellent performance, including extremely low dark current (~10-11 A), ultra-high photo-to-dark ratio (>105), satisfactory responsivity (1.05 A/W) and excellent selectivity for DUV band, compared to those with ordinary metal electrodes. The raising of photocurrent and responsivity is attributed to the increase of incident photons through Gr, and separated carriers caused by the built-in electric field formed at the interface of Gr and Ga2O3:Zn films. The proposed ideas and methods of tailoring Gr can not only improve the performance of devices, but more importantly, it contributes to the practical development of graphene.
关键词： gallium oxide,photodetector,deep ultraviolet,graphene interdigital electrodes,ultralow dark current
更新于2025-09-09 09:28:46
-
Modelling dark current and hot pixels in imaging sensors
摘要： A Gaussian mixture model with a structured covariance matrix was used to analyse image data recorded by a digital sensor under darkness to model the effects of temperature and duration of exposure on the expected value and on the variance of the sensor dark current, separately for ordinary and possibly defective pixels. The model accounts for two components of variance within each latent type: random noise in each image and lack of uniformity within the sensor; both components are allowed to depend on experimental conditions. The results seem to indicate that the dependence of the expected value of dark current on duration of exposure and temperature cannot be represented by a simple parametric model. The latent class model detects the presence of at least two types of hot pixels. If we order the latent classes in decreasing order of the class weights, the corresponding expected values and variances increase. The covariance structure that emerges from our analysis has an important implication: the sign and the relative size of pixels deviations from uniformity are invariant to experimental conditions.
关键词： components of variance,dark current,hot pixels,latent class models,dark frames,Gaussian mixtures
更新于2025-09-04 15:30:14