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Carrier reduction studies of type-II superlattice materials for very long wavelength infrared sensing
摘要: There are continuing efforts to develop type-II superlattice (SL) materials for very long wavelength infrared (VLWIR) detector applications. However, the SLs have high residual electron background doping densities that depend on SL growth conditions, which lead to shorter minority carrier lifetime and lower performance parameters than theoretically predicted. In this study, the authors compare the technical advantages of using InAs/GaInSb over InAs/GaSb SL with respect to reducing the electron doping levels. Our temperature-dependent electrical transport measurements show that the InAs/GaInSb SL design has a lower electron density than the InAs/GaSb SL with the same bandgap and have electron densities (mobilities) on the order of the mid 1011 cm?2 (25 000 cm2/V s). Since small period InAs/GaInSb SLs also produce greater Auger recombination suppression for a given VLWIR gap than the large period InAs/GaSb SL, the InAs/GaInSb SL appears to be a better candidate for long lifetime IR materials for future very long wavelength infrared devices.
关键词: very long wavelength infrared,mobility,InAs/GaSb,Auger recombination,InAs/GaInSb,type-II superlattice,carrier reduction,electron doping
更新于2025-09-19 17:15:36
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Microwave photocurrent from the edge states of InAs/GaInSb bilayers
摘要: We measure microwave photocurrent in devices made from InAs/GaInSb bilayers where both the insulating bulk state and conducting edge state were observed in the inverted-band regime, consistent with the theoretical prediction for a quantum spin Hall (QSH) insulator. It has been theoretically proposed that microwave photocurrent could be a unique probe in studying the properties of QSH edge states. To distinguish a possible photoresponse between a bulk state and helical edge state, we prepare a Hall bar and Corbino disk from the same wafer. Results show that the Corbino-disk samples have a negligible photocurrent in the bulk gap, while clear photocurrent signals from the Hall-bar samples are observed. This finding suggests that the photocurrent may carry information concerning the electronic properties of the edge states.
关键词: quantum spin Hall insulator,microwave photocurrent,helical edge states,InAs/GaInSb bilayers
更新于2025-09-04 15:30:14