Formation and control of MBE-ZnSe/GaAs heterointerface regrown homointerface

A combination of ex-situ HF-pretreatment and in-situ Se-pretreatment, (HF + Se)-pretreatment, is successfully applied to GaAs surface to control MBE-ZnSe/GaAs (100) heterointerface. C-V analysis of the interface indicates that the minimum state density, N,,i,(E), is considerably reduced to 1 X 10” cm- * eV- ‘, being one order of magnitude smaller than that for the standard chemically etched sample. The excess voltage drop across the n-ZnSe/n+-GaAs interface for current conduction is consistently reduced by the pretreatment, and the behavior of the Z-V characteristics can be theoretically fitted by using a previously proposed model considering interface charge and obtained 1LT,(E)s hapes. The quality of the ZnSe epilayer, which is assessed from X-ray diffraction and Raman scattering measurements, is also improved by the (HF + Se&pretreatment. Air-exposing and regrowth process is found to introduce a relatively high potential barrier at the ZnSe/ZnSe homointerface even when the regrowth is undertaken after a slight etching of the first grown epilayer