Influence of GaAs surface stoichiometry on the interface state density of as-grown epitaxial ZnSe/epitaxial GaAs heterostructures

Epitaxial ZnSe/epitaxial GaAs interfaces have been formed by molecular beam expitaxy and evaluated by several techniques including capacitance-voltage measurements. In the study reported here, the GaAs surface stoichiometry was systematically varied prior to the nucleation of ZnSe. A dramatic reduction of interface state density occurred when the GaAs epilayer was made As deficient. The resulting interface state densities of as-grown structures are comparable to values obtained with (Al,Ga)As/GaAs interfaces.