Electrical Characterization of Be-Doped InAs/InAsSb Superlattices

The InAs/InAsSb type-II superlattice materials studied to date for infrared detector applications have been residually n-type, but p-type absorber regions with minority carrier electrons can result in increased photodiode quantum efficiency, R$_{\mathrm{o}}$A, and detectivity. Therefore, Be-doped InAs/InAsSb superlattices were investigated to determine the p-type InAs/InAsSb superlattice material transport properties essential to developing high quality photodiode absorber materials. Hall measurements performed at 10K revealed that the superlattice converted to p-type with Be-doping of 3 x10$^{\mathrm{16}}$ cm$^{\mathrm{-3}}$ and the hole mobility reached 24 400 cm$^{\mathrm{2}}$/Vs. Photoresponse measurements at 10K confirmed the 175 meV bandgap and material optical quality.