Study of residual background carriers in midinfrared InAs∕GaSb superlattices for uncooled detector operation

Abstract

The midinfrared 7 ML InAs/8 ML GaSb superlattices (SLs) were grown by molecular beam epitaxy at growth temperatures between 370 and 430°C in order to study the intrinsic characteristic of background carriers. Grown SLs were all residual p type with carrier densities in the low 1011cm−2, and a minimum density of 1.8×1011cm−2 was obtained from the SL grown at 400°C. With increasing growth temperature, the in-plane carrier mobility decreased from 8740to1400cm2∕Vs due to increased interfacial roughness, while the photoluminescence intensity increased sixfold due to a decrease in the nonradiative defect densities.