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Microscopic FCA System for Depth-Resolved Carrier Lifetime Measurement in SiC
摘要： For high voltage SiC bipolar devices, carrier lifetime is an important parameter, and for optimization of device performance, we need to control the distribution of the carrier lifetime in a wafer. So far, there have been limited systems for depth-resolved carrier lifetime measurements without the necessity of making a cross sectional cut. In this study, we adopted a free carrier absorption technique and made local overlapping of the probe laser light with excitation laser light to develop depth-resolved carrier lifetime measurements. We named the developed system a microscopic FCA system and demonstrated measurement results for samples with and without intentional carrier lifetime distribution.
关键词： free carrier absorption,4H-SiC,carrier lifetime
更新于2025-09-23 15:22:29
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Upgraded CdZnTe Based on the Infrared Attenuation Spectrum
摘要： According to the infrared attenuation spectrum, we can know the conduction type and major point defect of CdZnTe crystals. Based on point defect modelling, an appropriate modus of atmosphere annealing was described in this paper. In this paper, annealing with Cd pressure control technology was used to upgrade p-CdZnTe and n-CdZnTe, respectively. Characterizations reveal that the optical and electrical performance of the CZT crystals is patently improved after annealing. Employment of the infrared attenuation spectrum as the annealing guideline has been veri?ed to be feasible and effectual in this paper.
关键词： CdZnTe,atmosphere annealing,infrared attenuation spectrum,free carrier absorption
更新于2025-09-19 17:15:36
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Efficiency Roadmap for Evolutionary Upgrades of PERC Solar Cells by TOPCon: Impact of Parasitic Absorption
摘要： Passivating contacts created via a thin interfacial oxide and a highly doped polysilicon layer, e.g., the TOPCon technology, are on the verge of being implemented in solar cell mass production. Investment decisions rely on R&D to identify the most promising implementation option, meaning a trustworthy roadmap based on predicted performance gains. This article shows how to thoroughly quantify the performance potential via numerical simulation, focusing on an evolutionary upgrade of a busbarless p-type bifacial passivated emitter rear cell (PERC) technology. We specifically highlight the need to consider not only the electrical gains of passivating contacts, but also the associated optical losses due to parasitic absorption in the polysilicon layers for front and rear illumination. The influence of free-carrier absorption in polysilicon on the solar cell optics is characterized on experimental test structures in order to verify our optical simulation model. Introducing TOPCon fully at the rear and also locally aligned to the front fingers can boost the PERC efficiency by approximately 1%abs. The final device is strongly limited by losses in the p-type c-Si bulk and phosphorus-doped front emitter. Consequently, the presented evolutionary TOPCon upgrades may well be of increased relevance for future improved p-PERC cells, as an alternative to the current focus on n-type TOPCon cells with boron emitter.
关键词： parasitic absorption,sentaurus TCAD,TOPCon,simulation,passivating contacts,Free-carrier absorption,roadmap,Quokka3
更新于2025-09-16 10:30:52
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Measurements of internal optical loss inside an operating laser diode
摘要： An experimental technique for measuring internal optical loss in high-power edge-emitting semiconductor lasers is demonstrated. The technique is based on coupling a probe beam into the waveguide of a pulse-pumped laser diode. It allows measuring free-carrier absorption (FCA) in a laser heterostructure at di?erent temperatures and at pump current levels up to 30 kA/cm2. Measurement results are presented for two laser heterostructure designs, which vary in the waveguide doping level and material. For both heterostructures, the pump current increase induces a signi?cant rise in FCA and a corresponding increase in internal optical loss, from 0.4–0.7 cm?1 at the threshold current to 2–2.5 cm?1 (65 °C, 27 kA/cm2). The gradient of the FCA current dependence is lower for the laser heterostructure with a doped GaAs waveguide, while the heterostructure with an undoped AlGaAs waveguide displays a larger increase in FCA but better internal quantum e?ciency at high currents. These results show that the proposed experimental method has signi?cant potential.
关键词： internal optical loss,heterostructure,free-carrier absorption,laser diode,high-power lasers
更新于2025-09-11 14:15:04