- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Precise Potential Observation of a Biased GaAs p-n Junction by <i>in situ</i> Phase-shifting Electron Holography; é????§??°??????GaAs p-n??￥??????é???2??o|é???-??·??????-??°????????￡???????????′è|3?ˉ?;
摘要： 昨今，半導体デバイスの研究開発において，動作中の電位温度 120 K の低温下でバルク試料の一部を薄膜化することにより作製した．この試料を電圧印加用 TEM 試料ホルダーにセットし，外部電源と電気的に接続することで TEM 内試料への電圧印加を可能とした．観察はホログラフィー電子顕微鏡(HF3300EH)を用いて加速電圧 300 kV で実施した．位相シフト法による位相再生には，入射電子線の初期位相をシフトして撮影した50枚のホログラムを用いた．
关键词： pn junction,cooling focused ion beam,electron beam holography
更新于2025-09-19 17:13:59
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Investigation of InGaAs subcell to InGaP subcell in InGaP/InGaAs/Ge multijunction solar cells with Analytical framework
摘要： Solar radiation consists of different electromagnetic spectrum. Single junction solar cell restricts complete absorption of incident radiations. This limits the efficiency of the solar cells. The way to overcome this calamity is to segregate and classify the entire spectrum into several spectral tiny regions according respective band gaps inherently. This process gives birth to multi-junction solar cell. This paper describes the mathematical model for multi-junction metamorphic inverted solar cell. Starting from their primitive need, present work includes the photovoltaic effect to electroluminescence extinction. MATLAB simulation has been used to demonstrate the photo-voltage and electroluminescence intensity. It is observed from the obtained results that generated photo-voltage increases with the illumination power while the electroluminescence intensity decreases.
关键词： Analytical solution of multi-junction cell,Single-walled nanotube solar cell,Metamorphic inverted solar cell characteristics,Inverted structure,Multi-junction solar cell
更新于2025-09-16 10:30:52
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Hollow Porous Gold Nanoshells with Controlled Nanojunctions for Highly Tunable Plasmon Resonances and Intense Field Enhancements for Surface-Enhanced Raman Scattering
摘要： Plasmonic metal nanostructures with nanogaps have attracted great interest owing to their controllable optical properties and intense electromagnetic fields that can be useful for a variety of applications, but precise and reliable control of nanogaps in three-dimensional nanostructures remains a great challenge. Here, we report the control of nanojunctions of hollow porous gold nanoshell (HPAuNS) structures by a facile oxygen plasma-etching process and the influence of changes in nanocrevices of the interparticle junction on the optical and sensing characteristics of HPAuNSs. We demonstrate a high tunability of the localized surface plasmon resonance (LSPR) peaks and surface-enhanced Raman scattering (SERS) detection of rhodamine 6G (R6G) using HPAuNS structures with different nanojunctions by varying the degree of gold sintering. As the neck region of the nanojunction is further sintered, the main LSPR peak shifts from 785 to 1350 nm with broadening because the charge transfer plasmon mode becomes more dominant than the dipolar plasmon mode, resulting from the increase of conductance at the interparticle junctions. In addition, it is demonstrated that an increase in the sharpness of the nanojunction neck can enhance the SERS enhancement factor of the HPAuNS by up to 4.8-fold. This enhancement can be ascribed to the more intense local electromagnetic fields at the sharper nanocrevices of interparticle junctions. The delicate change of nanojunction structures in HPAuNSs can significantly affect their optical spectrum and electromagnetic field intensity, which are critical for their practical use in a SERS-based analytical sensor as well as multiple-wavelength compatible applications.
关键词： sintering,plasma etching,nanoporous gold,nanocrevice junction,surface-enhanced Raman scattering,plasmonic nanostructure
更新于2025-09-16 10:30:52
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Development and Analysis of Wafer-Bonded Four-Junction Solar Cells Based on Antimonides With 42% Efficiency Under Concentration
摘要： The highest solar cell efficiencies today are reached with four-junction devices under concentrated illumination. The optimal bandgap combination for realistic four-junction cells is modelled to be 1.89/1.42/1.05/0.68 eV and indeed promises for efficiencies >50%. We present the development and analysis of a wafer-bonded four-junction solar cell based on GaInP/GaAs/GaInAs//GaInAsSb. This concept allows for the implementation of these ideal bandgaps and exhibits at present an efficiency of 42.0±2.5% at a concentration of 599x AM1.5d. The present loss mechanisms in this device are analyzed, which are dominated by current losses due to mismatched subcell currents and absorbing passive layers. Under the assumption of proper current matching, this device would achieve an efficiency above 44%.
关键词： metal-organic vapour phase epitaxy (MOVPE),multijunction solar cells,wafer bonding,Antimonides,four-junction solar cells
更新于2025-09-16 10:30:52
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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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A new metal transfer process for van der Waals contacts to vertical Schottky-junction transition metal dichalcogenide photovoltaics
摘要： Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin optoelectronic devices due to their high absorption coefficients and intrinsically passivated surfaces. To maintain these near-perfect surfaces, recent research has focused on fabricating contacts that limit Fermi-level pinning at the metal-semiconductor interface. Here, we develop a new, simple procedure for transferring metal contacts that does not require aligned lithography. Using this technique, we fabricate vertical Schottky-junction WS2 solar cells, with Ag and Au as asymmetric work function contacts. Under laser illumination, we observe rectifying behavior and open-circuit voltage above 500 mV in devices with transferred contacts, in contrast to resistive behavior and open-circuit voltage below 15 mV in devices with evaporated contacts. One-sun measurements and device simulation results indicate that this metal transfer process could enable high specific power vertical Schottky-junction transition metal dichalcogenide photovoltaics, and we anticipate that this technique will lead to advances for two-dimensional devices more broadly.
关键词： van der Waals contacts,transition metal dichalcogenides,photovoltaics,metal transfer process,Schottky-junction
更新于2025-09-16 10:30:52
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Analysis of Thin-film Direct Band-gap SiGeSn alloy based Heterostructure Solar Cell Featuring SiGe Absorber Layer
摘要： Ternary alloy Si1-x-yGexSny or GexSn1-x made up of group IV elements has been receiving attention from researchers in recent years due to its direct band gap nature. In this work, we investigate the performance of solar cells made with this alloy. We have proposed a n+ Si1-x-yGexSny (emitter)/p- Si1-xGex (absorber)/p- Si1-x-yGexSny (base) /p+ Si1-x-yGexSny (back surface field layer: BSF) based solar cell grown on Si1-x-yGexSny substrate. The calculated values are compared with the values for existing Si1-xGex solar cells and comparatively improved performances are obtained for the proposed structure. The effects of different absorber layer thickness, doping concentrations of the absorber and BSF layers, Ge concentration in Si1-xGex and Sn concentration in Si1-x-yGexSny are also studied for the proposed structure. Conversion efficiency as high as 19.9% for substrate thickness as low as 10 μm has been obtained for the proposed structure. The low value of substrate thickness and high efficiency make the proposed structure attractive as a low-cost device for applications in spacecraft and satellites.
关键词： conversion efficiency,TCAD simulation,single junction solar cell,Si1-x-yGexSny alloys
更新于2025-09-16 10:30:52
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Impact of K+ Doping on Modulating Majority Charge Carrier Type and Quality of Perovskite Thin Films by Two-step Solution Method for Solar Cells
摘要： Traditional hetero-junction perovskite solar cells are composed of light-absorbing layers, charge carrier-transporting layers, and electrodes. Recently, a few papers on homo-junction perovskite solar cells have been studied. Here, we studied the effect of K+ doping on TiO2/PbI2 interface quality, perovskite film morphology, photo-physical properties, and majority carrier type. In particular, the K+ extrinsic doping can modulate the majority carrier type of the perovskite thin film. The study indicated that the interface between the perovskite layer and the TiO2 layer deteriorates with the K+ doping concentration, affecting the electron transport ability from the perovskite film to the TiO2 layer and the photo-physical properties of the perovskite layer by K+ doping. In addition, the majority charge carrier type of perovskite thin films can be changed from n-type to p-type after K+ extrinsic doping, and the corresponding hole concentration increased to 1012 cm?3. This approach of modulating the majority charge carrier type of perovskite thin film will pave the way for the investigation of perovskite homo-junction by extrinsic doping for solar cells.
关键词： p-n junction,perovskite solar cells,K+ doping,photo-physical properties
更新于2025-09-16 10:30:52
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Enhanced metal assisted etching method for high aspect ratio microstructures: Applications in silicon micropillar array solar cells
摘要： A solar cell device, fabricated on high density array cylindrical pillars, enables photogenerated carrier collection in the radial direction, thus shortening the path length of the carriers reaching the junction. It also provides advantages over conventional planar junction solar cells, such as reduced surface re?ectance and enhanced light trapping. In this study, highly ordered Si micropillars were fabricated by photolithography and metal assisted etching (MAE) methods. It is shown that the use of ethanol as a solvent during the etching process and increasing HF concentration in the MAE solution both improve the quality of the surfaces of the pillars. Micropillars with smooth sidewalls and a high aspect ratio were obtained in this way. Solar cells with a radial junction were then fabricated on these micropillars. Standard doping, SiO2/SiNx passivation, and metallisation steps were carried out for the fabrication of solar cells with di?erent micropillar lengths. A signi?cant decrease in re?ectance values was observed as the micropillar length increased, as expected. Solar cell short circuit current density (Jsc) and e?ciency (η) of the solar cells tended to increase with micropillar length up to 11.5 μm and then decrease due to increased surface recombination. The maximum e?ciency achieved in this study is 17.26%.
关键词： Solar cell,Ethanol,Micropillar,Metal assisted etching,High aspect ratio,Radial junction
更新于2025-09-16 10:30:52
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Thermal Analysis of the Factors Influencing Junction Temperature of LED Panel Sources
摘要： Limiting junction temperature Tj and maintaining its low value is crucial for the lifetime and reliability of semi-conductive light sources. Obtaining the lowest possible temperature of Tj is especially important in the case of LED panels, where in a short distance there are many light sources installed, between which there occurs mutual thermal coupling. The article presents results of simulation studies connected with the in?uence of construction and ambient factors that in?uence the value of junction temperature of exemplary LED panel sources. The in?uence of radiator’s construction, printed circuit boards, as well as the in?uence of ambient factors, such as ambient temperature Ta and air ?ow velocity v were subjected to the analysis. Numerical calculations were done in the FloEFD software of the Mentor Graphics company, which is based on computational ?uid dynamics (CFD). For construction of the LED thermal panel model the optical e?ciency ηo and real thermal resistance Rthj-c were determined in a laboratory for the applied light sources.
关键词： CFD,LED,junction temperature,heat sink
更新于2025-09-16 10:30:52