Transport properties in InAs/InAsSb type-II superlattices: From MWIR to VLWIR

In recent years, InAs/InAsSb type-II superlattices have emerged as promising candidates to rival state-of-the-art mercury cadmium telluride systems for mid-wavelength infrared (MWIR) imaging applications. However, extending their performance to longer wavelengths remains a challenge, as the carrier transport properties tend to degrade with the increasing superlattices period required to achieve such wavelengths. Consequently, a detailed investigation of the temperature dependence of carrier transport properties as a function of cutoff wavelength is critical for addressing the forthcoming challenges. In this study, we investigated the carrier transport properties of a large set of InAs/InAsSb type-II superlattices samples, with cutoff wavelength spanning from MWIR to very-long wave infrared (VLWIR). The temperature dependence of the minority carrier lifetime was examined and compared across samples. We also analyzed the temperature dependence of hole diffusion length and mobility using a quantum efficiency model. The mobility of the MWIR samples (≈ 1.6 cm2/V s) was approximately one order of magnitude lower than that of the samples with longer cutoff wavelengths. Further, we extended our analysis by extracting minority transport properties from simulations of dark current density. Our results show that mobility increases with cutoff wavelength, ranging from ≈1.6 cm2/V s for MWIR samples, to ≈ 27 cm2/V s for LWIR, and up to ≈ 200 cm2/V s for VLWIR.