Interface States in p-Type GaAs/GaAs_1-xBi_xHeterostructure

Abstract

The characteristics of interface states in a GaAs/GaAs 1- x Bi x heterointerface have been evaluated by capacitance–frequency measurements, thermal admittance spectroscopy, and isothermal capacitance transient spectroscopy. The interface states density D it is evaluated to be approximately 9 ×10 11 cm -2 eV -1 for the first time. The large density is probably caused by the fact that the surface of GaAs and GaAs 1- x Bi x 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-GaAs 1- x Bi x heterointerface, which is on the same order as other III–V heterointerfaces such as GaAs/GaAs 0.97 N 0.03 and In 0.5 Ga 0.5 P/Al 0.25 Ga 0.75 As.