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Development and Study of the pa??ia??n GaAs/AlGaAs Tunnel Diodes for Multijunction Converters of High-Power Laser Radiation
摘要： The creation of connecting tunnel diodes with a peak tunneling-current density higher than the density of the short-circuit current of photoactive p–n junctions is an important task in the development of multijunction photoconverters (III–V) of high-power optical radiation. Basing on numerical simulation of the J–U characteristics of tunnel diodes, a method is proposed for increasing the peak tunneling-current density by including a thin undoped i-type layer with a thickness of several nanometers between degenerate layers of the tunnel diode. The p–i–n-GaAs/Al0.2Ga0.8As structures of the connecting tunnel diodes with a peak tunneling-current density of up to 200 A/cm2 are grown by molecular-beam epitaxy.
关键词： quantum tunneling,molecular-beam epitaxy,tunnel diode,multijunction photoconverter,current–voltage characteristic
更新于2025-09-23 15:21:01
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Numerical optimisation and recombination effects on the vertical-tunnel-junction (VTJ) GaAs solar cell up to 10,000 suns
摘要： Ultra-high concentrator photovoltaic systems (UHCPV), usually referred to CPV systems exceeding 1000 suns, are signalled as one of the most promising research avenues to produce a new generation of high-efficiency and low-cost CPV systems. However, the structure of current concentrator solar cells prevents their development due to the unavoidable series resistance losses at such elevated concentration ratios. In this work, we investigate the performance of the so-called vertical-tunnel-junction (VTJ), recently introduced by the authors, by using advance TCAD. In particular, we carry out an optimisation procedure of the key parameters that affect its performance and conduct a deep investigation of the impact of the main recombination mechanisms and of sun concentration up to 10,000 suns. The results indicate that the performance of the novel structure is not significantly affected by these two factors. A record efficiency of 32.2% at 10,000 suns has been found. This represents a promising way to obtain state-of-the-art efficiencies above 30% for single-band-gap cells, and offers a new route towards the development of competitive CPV systems operating at ultra-high concentration fluxes.
关键词： Tunnel diode,Concentrator photovoltaics,Vertical solar cells,Series resistance,Gallium arsenide (GaAs)
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Thin Film Photosensor Integrated on Planar Waveguide for Lab-an-Chip Applications
摘要： We report on high-frequency performance and temperature stability of zero-bias GaAsSb/InAlAs/InGaAs tunnel diodes for millimeter-wave detection in 220–330-GHz band. The average voltage sensitivity of 1400 V/W has been achieved in 0.8 × 0.8 μm2 mesa devices at room temperature. Measured current–voltage characteristics revealed a superior temperature stability of the devices compared with Schottky barrier diodes. The expected sensitivity variations over a temperature range from T = 17–300 K are 1.7 dB.
关键词： tunnel diode,tunneling,Backward diode,millimeter wave and terahertz detectors,semiconductor nanostructures
更新于2025-09-19 17:13:59
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Counteracting the Photovoltaic Effect in the Top Intergenerator Part of GaInP/GaAs/Ge Solar Cells
摘要： The “top” intergenerator part situated between the GaInP and GaAs subcells (electric power generators) is analyzed. The shape of the light current–voltage characteristics and the Voc–Jsc (open-circuit voltage–short-circuit current) dependence are examined. It is found that the p+–n+ tunnel heterojunction situated in the “top” intergenerator part can operate as a photoelectric source counteracting the base p–n junctions. In this case, the Voc–Jsc characteristic has a descending part, and a sharp jump can be observed. This undesirable effect becomes weaker with increasing peak current of the tunnel junction.
关键词： current–voltage characteristics,counteracting electromotive force,tunnel diode,photovoltaic characteristics,multiple-junction solar cells,concentrated solar light
更新于2025-09-16 10:30:52
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Anomalies in Photovoltaic Characteristics of Multijunction Solar Cells at Ultrahigh Solar Light Concentrations
摘要： An anomaly appearing in the photovoltaic characteristics of triple-junction GaInP/GaAs/Ge and of the corresponding double-junction GaInP/GaAs solar cells at ultrahigh concentrations (more than 2000 suns) of incident light has been studied. The light current–voltage characteristics at various concentration ratios of incident light and the dependence of the open-circuit voltage on the photogenerated current were analyzed. It was shown that the anomaly is observed due to the tunnel diode connected back-to-back between the GaInP and GaAs subcells. This diode absorbs photons that pass across the GaInP layers and creates a counter photovoltage.
关键词： tunnel diode,multijunction solar cell,photovoltaic characteristics,concentrated solar light,counter electromotive force,current–voltage characteristics
更新于2025-09-16 10:30:52
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Heterogeneous integration of InAs/GaSb tunnel diode structure on silicon using 200 nm GaAsSb dislocation filtering buffer
摘要： An InAs/GaSb tunnel diode structure was heterogeneously integrated on silicon by solid source molecular beam epitaxy using a 200 nm strained GaAs1-ySby dislocation filtering buffer. X-ray analysis demonstrated near complete strain relaxation of the metamorphic buffer and a quasi-lattice-matched InAs/GaSb heterostructure, while high-resolution transmission electron microscopy revealed sharp, atomically abrupt heterointerfaces between the GaSb and InAs epilayers. In-plane magnetotransport analysis revealed Shubnikov-de Haas oscillations, indicating the presence of a dominant high mobility carrier, thereby testifying to the quality of the heterostructure and interfaces. Temperature-dependent current-voltage characteristics of fabricated InAs/GaSb tunnel diodes demonstrated Shockley-Read-Hall generation-recombination at low bias and band-to-band tunneling transport at high bias. The extracted conductance slope from the fabricated tunnel diodes increased with increasing temperature due to thermal emission (Ea ～ 0.48 eV) and trap-assisted tunneling. Thus, this work illustrates the significance of defect control in the heterointegration of metamorphic InAs/GaSb tunnel diode heterostructures on silicon when using GaAs1-ySby dislocation filtering buffers.
关键词： dislocation filtering buffer,silicon,tunnel diode,InAs/GaSb,heterogeneous integration,molecular beam epitaxy
更新于2025-09-10 09:29:36
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[IEEE 48th European Solid-State Device Research Conference (ESSDERC 2018) - Dresden (2018.9.3-2018.9.6)] 2018 48th European Solid-State Device Research Conference (ESSDERC) - Electric Double Layer Esaki Tunnel Junction in a 40-nm-Length, WSe2 Channel Grown by Molecular Beam Epitaxy on Al203
摘要： An electric-double-layer (EDL) Esaki junction is demonstrated for the first time in a molecular beam epitaxy-grown WSe2 thin-film field-effect transistor (FET). By carefully engineering the strength and spatial extent of the electron-cation and hole-anion EDLs at the WSe2/solid polymer electrolyte polyethylene oxide: cesium perchlorate (PEO:CsClO4) interface, degenerate and abrupt doping profiles are obtained, which are key to enable interband tunneling operations. Gate-tunable negative differential resistance (NDR) is measured at temperatures up to 140 K, with a maximum peak-to-valley current ratio (PVCR) of 3.5 at 110 K, in a 40 nm-long channel device.
关键词： tunnel diode,Esaki tunneling,electric double layer,tungsten diselenide,cesium perchlorate,polyethylene oxide
更新于2025-09-04 15:30:14