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We have systematically investigated highly mismatched AlInSb photodiodes grown on GaAs substrates operating in the mid-infrared range. A novel characterization method was introduced to analyze the recombination mechanism within an active layer of the devices, which revealed a high conductance stemming from the leaky behavior of dislocations. The introduction of a dislocation filter layer successfully reduced threading dislocations and improved resistance area product of photodiodes, leading to high detectivity at room temperature. [ABSTRACT FROM AUTHOR]

We investigated the electrical and optical properties of a highly mismatched AlInSb/GaAs photodiode sensor working in the mid-infrared range at room temperature. A substantial increase in the device performance was achieved by controlling the strain energy density in the dislocation filter layers and barrier layers to reduce the density of threading and interfacial dislocations, respectively. The resulting photodiode showed a high resistance-area product of 0.24 Ω cm2 and a peak detectivity of 2.2 × 109 cm Hz1/2 W–1 at 3.3 μm. [ABSTRACT FROM AUTHOR]

Abstract: We examined the role of localized electrons in the accumulation layer of Sn-doped InSb quantum wells (QWs) with various wellwidths . At liquid He temperatures, the samples with the sheet resistance for exhibit the variable-range hopping (VRH), while those with exhibit weak localization (WL), where is the quantum resistance. In particular, a part of the electrons (with density of ) from Sn donors are trapped at the interface states at low temperatures below 77 K. In the WL regime, we observed the small positive magnetoresistance (MR) peak arising from the weak anti-localization (WAL) in the presence of spin-orbit interaction (SOI). In contrast to the WAL in WL regime, the low-field MR in the VRH regime remains entirely negative surviving the SOI, indicating that the hopping MR due to the quantum interference (QI) is completely negative regardless of the SOI. This result supports the predictions based on the directed-path approach for forward-scattering paths ignoring the back-scattering return loops for the QI in the VRH. [Copyright &y& Elsevier]