Demonstration of interface-scattering-limited electron mobilities in InAs/GaSb superlattices

In-plane transport in InAs/GaSb type-II superlattices (SLs) is a sensitive indicator of SL growth quality and of the eventual performance of devices made from these materials. The in-plane mobility of electrons that move predominantly in the InAs layer is affected by a number of intrinsic and extrinsic scattering mechanisms, including interface roughness scattering (IRS). The hallmark of classic IRS-limited transport in SLs and quantum wells is the sixth power dependence of mobility on layer width. While IRS-limited transport was demonstrated in a number of SL and quantum well systems, it has never been demonstrated in the important InAs/GaSb SL material. We performed temperature dependent Hall effect measurements on a series of InAs/GaSb SLs with a fixed GaSb layer width and a variable InAs layer width, $d$. The low temperature (10K) in-plane electron mobilities, $\mu $, as a function $d$ behave as $\mu \propto d^{6.20}$, which follows the classic sixth power dependence expected from theory.