Performance analysis of W-, N-, and M-Structures for T2SL Detectors

Type-II superlattices (T2SLs) are promising for infrared photodetection due to their tunable band gaps and potentially reduced Auger recombination. In this work, we investigate three device configurations based on the M, N, and W structures that integrate an AlSb barrier within GaSb/InAs T2SL periods to enhance electron–hole overlap for increased absorption. We carry out k·p simulations encompassing 400 GaSb/InAs thickness combinations each with six AlSb layer thicknesses (1–6 monolayers). From each set of 400 simulations, a single mid-wave high-performance structure is identified using a figure of merit derived from the computed band parameters. This results in six selected T2SLs for M, N, and W configurations that exhibit optimum performance. Subsequently, we employ a quantum transport approach, the non-equilibrium Green’s function (NEGF), to evaluate the transport properties of these selected designs under varying device lengths and temperatures. Comparisons with standard T2SL photodetectors will clarify the performance gains afforded by these barrier-enhanced configurations.