Carrier transport in III-V type-II superlattices for MWIR photodetection

InAs and GaSb are typically used to design state-of-the-art photodetectors for various applications across the mid-wavelength infrared spectrum. Several breakthroughs have been made in such infrared detectors. Using the k.p band structure model, we analyze the transport behavior of carriers in 8ML/8ML InAs/GaSb-based type-II superlattices (SLs). Going beyond the commonly employed relaxation time approximation (RTA) via the Rode iterative method [1], we shed light on the carrier’s mobility limiting factors and briefly discuss the sources of different scattering mechanisms that play a key role in such superlattices. In particular, we pay attention on how interface roughness scattering and polar optical phonon scattering mechanisms affect the temperature and carrier density dependence of both the mobility and the conductivity. Our findings demonstrate that, in the case of an inelastic scattering mechanism, the RTA fails to accurately capture the mobility characteristics. Furthermore, we show that the Hall scattering factor is not always one, highlighting the need for caution when utilizing it as a constant in computations involving drift mobility and carrier concentration. Our findings provide a detailed microscopic understanding of the dynamic behavior of carriers in such SLs.

Reference:

[1] Rode, D. L. "Low-field electron transport." In Semiconductors and semimetals, vol. 10, pp. 1-89. Elsevier, 1975.