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Study on Optical Properties and Waveguide Structure Optimization of Semiconductor Lasers with InGaAs Quantum Well
摘要： InGaAs quantum wells (QWs) are grown on GaAs substrates by metal-organic chemieal vapor deposition (MOCVD). Sample grown on substrates (100) oriented 2° off towards <111> exhibits relatively high photoluminescence (PL) intensity and narrow full-width at half-maximum (FWHM). Increasing growth rate leads to the enhancement of PL intensity and decrease of FWHM. Asymmetric waveguide layers are applied to reduce the confinement factor of base mode and increase the loss of higher-order mode.
关键词： MOCVD,waveguide structure,photoluminescence,InGaAs quantum wells,semiconductor lasers
更新于2025-09-23 15:19:57
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High-Efficiency Multiple Quantum Well Triple-Junction Tandem Solar Cell
摘要： This work shows the design of a high-efficiency solar cell in an indium-gallium-arsenide/–gallium-arsenide multiple quantum well (MQW) structure. The main concerns regarding the solar cell are its fabrication complexity, design complexity, and efficiency. Tandem solar cells are designed to absorb the maximum amount of solar energy. In a tandem structure, different positive-negative junctions are responsible for absorbing different portions of the solar spectrum. Besides this, the embedded MQW structure also helps to increase the efficiency of the solar cell. The maximum efficiency of the tandem solar cell in the different material structures is reported to be around 45%–46%. Proper matching of different material parameters such as the lattice-matched semiconductor and thickness of the tandem solar cell can increase the efficiency of the solar cell. This paper introduces a tandem solar cell having an efficiency of around 50%. This comparative study shows the improved performance of the proposed solar cell. A graphical user interface is also developed for solar cell simulation.
关键词： tandem solar cell,multi-quantum well,InGaAs-GaAs,quantum well,Solar cell
更新于2025-09-23 15:19:57
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Gate Bias and Length Dependences of Total-Ionizing-Dose Effects in InGaAs FinFETs on Bulk Si
摘要： We evaluate the total-ionizing-dose (TID) responses of InGaAs nMOS FinFETs with different gate lengths irradiated with 10-keV X-rays under different gate biases. The largest degradation after irradiation occurs at VG = -1 V. Radiation-induced trapped positive charge dominates the TID response of InGaAs FinFET transistors, consistent with previous results for InGaAs multi-fin capacitors. Shorter gate-length devices show larger radiation-induced charge trapping than longer gate-length devices, most likely due to the electrostatic effects of trapped charge in the surrounding SiO2 isolation and SiO2/Si3N4 spacer oxides. 1/f noise measurements indicate a high trap density and a non-uniform defect-energy distribution, consistent with a strong variation of effective border-trap density with surface potential.
关键词： 1/f noise,FinFETs,InGaAs,Total-Ionizing-Dose,Bulk Si,border-trap,Gate length dependence,III-V
更新于2025-09-19 17:15:36
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Temperature dependence of inter-dot electron-spin transfer among laterally coupled excited states in high-density InGaAs quantum dots
摘要： The temperature dependence of interdot spin-transfer dynamics at laterally coupled excited states (ESs) in high-density InGaAs quantum dots (QDs) was studied using spin- and time-resolved photoluminescence spectroscopy. At low temperatures below 100 K, temporary suppression of electron-spin polarization decay due to selective relaxation of minority spins from emissive ESs to lower-energy states in neighboring QDs was observed. In the temperature range from 20 K to 140 K, thermal activation of electron spins from lower-energy QD states to higher-energy states via interdot transfer prevents the aforementioned selective relaxation of minority spins, leading to a faster decay of electron-spin polarization during light emission. At high temperatures above 140 K, reinjection of depolarized electron spins from barriers after thermal escape from QD ESs accelerates the further decay of the electron-spin polarization, wherein the electron spins can be activated via ladderlike interdot transfer. These findings indicate that the suppression of reinjection of electron spins from barriers in a high-density QD system is crucial for maintaining high electron-spin polarization during light emission at high temperatures.
关键词： electron-spin polarization,InGaAs quantum dots,interdot spin-transfer dynamics,spin- and time-resolved photoluminescence spectroscopy,temperature dependence
更新于2025-09-19 17:13:59
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Multicolor Broadband and Fast Photodetector Based on InGaAsa??Insulatora??Graphene Hybrid Heterostructure
摘要： Broadband light detection is crucial for a variety of optoelectronic applications in modern society. As an important-near infrared (NIR) photodetector, InGaAs PIN photodiodes demonstrate high detection performance. However, they have a limited response range because of optical absorption by the window layer or substrate. To exploit the broadband absorption capability of narrow-bandgap InGaAs, a phototransistor based on a hybrid InGaAs-SiO2-graphene heterostructure is presented. In this system, graphene serves as a transparent conducting channel to sense optical absorption in the InGaAs. In contrast to InGaAs PIN photodiodes, the hybrid InGaAs phototransistor demonstrates multicolor photodetection over a broadband wavelength range from the ultraviolet to NIR. Furthermore, it manifests a high photoresponsivity of above 103 A W?1 under weak light irradiation, a large external quantum efficiency, and a fast response speed of 200 kHz. The results pave the way for the development of high-performance broadband photodetectors based on mixed-dimensional heterostructures.
关键词： InGaAs,photodetectors,graphene
更新于2025-09-19 17:13:59
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Comparison of operational performance and analytical model of high concentrator photovoltaic thermal system at 2000 concentration ratio
摘要： This paper presents the development of a model based on efficiency equations to evaluate the performance of an HCPV/T system and compares its outputs with data of an operational case-study system installed in Palermo, Italy. The model is validated with data of the operational system to show real performance. The model can evaluate (a) the electric efficiency of the InGaP/InGaAs/Ge TJ solar cell and (b) electrical and thermal power/energy production potential of one module. The model predictions are compared with experimental electric and thermal data by obtaining linear regression plots of experimental results vs. analytical results; the R2 for experimental electrical and thermal results are 0.91 and 0.87 respectively. Using the model, the evaluated average daily analytical and experimental InGaP/InGaAs/Ge TJ solar cell efficiencies are 33 % and 25 % respectively; with a maximum daily experimental value of 30 %. It was found that the annual analytical and potential (based on derived equations from experimental data) electric energy produced by one module are 158 kWh/m2/year and 144 kWh/m2/year respectively, while the annual analytical and potential thermal energy are 375 kWh/m2/year and 390 kWh/m2/year respectively.
关键词： InGaP/InGaAs/Ge TJ solar cell,HCPV/T system,analytical model,thermal energy,electric efficiency
更新于2025-09-19 17:13:59
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Hydrodynamic simulation of InGaAs terahertz oscillations
摘要： Terahertz (THz) oscillations in n+nn+ In0.53Ga0.47As diodes have been simulated with the use of a time-dependent hydrodynamic model. Under proper biased voltage and doping concentration, THz self-oscillations show up. The current self-oscillations originate from the formation and propagation of electric field domains in In0.53Ga0.47As diodes. The In0.53Ga0.47As device studied here may be presented as an excellent candidate as a solid-state THz source for monolithic integration.
关键词： Terahertz oscillations,hydrodynamic model,InGaAs
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Pulsed Power & Plasma Science (PPPS) - Orlando, FL, USA (2019.6.23-2019.6.29)] 2019 IEEE Pulsed Power & Plasma Science (PPPS) - 2D Simulations of the NS-Laser Shock Peening
摘要： We report on the impact of H2 high-pressure annealing (HPA) onto In0.7Ga0.3As MOSCAPs and quantum-well (QW) MOSFETs with Al2O3/HfO2 gate-stack. After HPA with process condition of 300 °C, H2 ambient and pressure of 20 atm, we observed notable improvements of the capacitance–voltage (CV) characteristics in InGaAs MOSCAPs with Al2O3/HfO2 gate-stack, such as reduction of equivalent-oxide-thickness and less frequency dispersion in the accumulation region. There was 20% improvement of the interfacial trap density ( Dit). Then, we incorporated the HPA process into the fabrication of sub-100-nm In0.7Ga0.3As QW MOSFETs, to investigate the impact of HPA process. After HPA process, the device with L g = 50 nm exhibits improved subthreshold-swing (SS) = 105 mV/decade, in comparison with SS = 130 mV/decade for the reference device without HPA process. Finally, we carried out reliability assessment under a constant-voltage-stress (CVS), and it turns out that the HPA process was effective in mitigating a shift of threshold voltage ((cid:2)VT ) during the CVS. These are attributed to the effective passivation of oxide traps in the high-k dielectric layer and interfacial traps, after HPA process in the H2 ambient.
关键词： interfacial trap density (Dit),subthreshold-swing (SS),high-pressure annealing,atomic layer deposition (ALD),InGaAs MOSFET
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Thermal and resistive losses in InGaAs metamorphic laser (λ = 1064?nm) power converters with over 50% efficiency
摘要： The topic of the work is the metamorphic InGaAs heterostructure for laser power converters with λ=1064 nm. The problem of conversion efficiency under various conditions of incident radiation is investigated: with uniform illumination with a Xe-lamp, with a continuous high-power laser, and with a pulsed laser. The thermal coefficient α=?V/?T of overheating is calculated for continuous laser. An increasing contribution of resistive losses, associated with the spreading resistance, for a focused laser beam (when the focus spot is smaller than the photoactive area of a sample) is discussed. It has been demonstrated that with a unfocused laser beam (the mode corresponding to the practical case of wireless energy transmission), the conversion efficiency of laser radiation is compared with the efficiency under a Xe-lamp. For laser power converters with optimal (according to calculated from spectral characteristics MCC diffusion length) thickness, the efficiency of more than 48% (λ=1064 nm) within 1.3–13 W/cm2 incident power was demonstrated with 50.6% maximum at 5.2 W/cm2.
关键词： resistive losses,efficiency,thermal losses,InGaAs,metamorphic laser,power converters
更新于2025-09-19 17:13:59
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InGaAs/graphene infrared photodetectors with enhanced responsivity
摘要： High responsivity is a vital aim of photodetectors research. Based on the photogating effect, ultra-high responsivity can be realized by combining the high mobility of graphene and strong light absorption of other materials. Due to long carrier lifetime and low mobility, quantum dots(QDs) are usually used to form hybrid photodetectors with graphene. However, hybrid photodetectors of graphene with materials possessing higher mobility are rarely studied at present. In this paper, the hybrid photodetector of graphene and InGaAs is studied. We fabricated and measured pure InGaAs photodetectors, hybrid photodetectors of the whole graphene on InGaAs surface and hybrid photodetectors of graphene nanoribbons(GNRs) on InGaAs surface. It is found that, compared to pure InGaAs photodetectors, the responsivity of the whole graphene on InGaAs surface devices increases by 14.7 times, which is 7.66 A W?1, and the response time is twice faster. We also found that the negative back voltage can increase the photocurrent by modulating the Fermi energy of graphene and barrier height of the hybrid photodetectors. The illuminated area effect on various devices area was discussed in this study. In terms of theoretical mechanization, as high mobility materials, both graphene and InGaAs could generate and transport carriers in this hybrid photodetector under optical illumination. The photoexcited holes in InGaAs enter graphene while the photoexcited electrons in graphene enter InGaAs due to the built-in ?eld, which leads to a charge build-up on both sides of the junction and a strong photogating effect on the channel conductance. The results of this study are of novel signi?cance for the development of infrared detectors based on graphene.
关键词： infrared photodetectors,responsivity,graphene,InGaAs
更新于2025-09-19 17:13:59