Interface States in p-Type GaAs/GaAs_1-xBi_xHeterostructure

Abstract

The characteristics of interface states in a GaAs/GaAs1-xBix heterointerface have been evaluated by capacitance–frequency measurements, thermal admittance spectroscopy, and isothermal capacitance transient spectroscopy. The interface states density Dit is evaluated to be approximately 9 ×1011 cm-2 eV-1 for the first time. The large density is probably caused by the fact that the surface of GaAs and GaAs1-xBix are shown to be nonmetallic and metallic, respectively. The interface states density is reduced by half by insertion of a Bi graded layer into the GaAs/p-GaAs1-xBix heterointerface, which is on the same order as other III–V heterointerfaces such as GaAs/GaAs0.97N0.03 and In0.5Ga0.5P/Al0.25Ga0.75As.