Electroluminescence of type II broken-gap p-Ga0.84In0.16As0.22Sb0.78∕p-InAs heterostructures with a high-mobility electron channel at the interface

Abstract

Ga 0.84 In 0.16 As 0.22 Sb 0.78 quaternary solid solutions, lattice matched to InAs, were grown by liquid phase epitaxy on (100)-oriented p-InAs substrates from In-rich melt. The p-type Ga0.84In0.16As0.22Sb0.78 layers were intentionally undoped or slightly doped with Sn to the hole concentration about p∼5×1016cm−3. This allowed us to obtain a high-mobility∼(3.5−5.0)×104cm2V−1s−1 electron channel at the type II broken-gap p-Ga0.84In0.16As0.22Sb0.78∕p-InAs heterointerface. Low-temperature (T=5K) electroluminescence spectra exhibited two pronounced emission bands hν1=0.372eV and hν2=0.400eV under forward bias. The emission band hν2 was split into two lines and was attributed to interband transitions through acceptor and valence-band states in the bulk InAs, whereas emission band hν1 was ascribed to interface-related radiative transitions of electrons from the two-dimensional electron channel to the interface states at the p-Ga0.84In0.16As0.22Sb0.78∕p-InAs heteroboundary.