FORMATION AND CONTROL OF MBE-ZNSE GAAS HETEROINTERFACE AND REGROWN HOMOINTERFACE/

A combination of ex-situ HF-pretreatment and in-situ Se-pretreatment, (HF + Se)-pretreatment, is successfully applied to GaAs surface to con trol MBE-ZnSe/GaAs (100) heterointerface. C-V analysis of the interfac e indicates that the minimum state density, N-ss,N-min(E), is consider ably reduced to 1 x 10(11) cm(-2) eV(-1), being one order of magnitude smaller than that for the standard chemically etched sample. The exce ss voltage drop across the n-ZnSe/n(+)-GaAs interface for current cond uction is consistently reduced by the pretreatment, and the behavior o f the I-V characteristics can be theoretically fitted by using a previ ously proposed model considering interface charge and obtained N-ss(E) shapes. The quality of the ZnSe epilayer, which is assessed from X-ra y diffraction and Raman scattering measurements, is also improved by t he (HF + Se)-pretreatment. Air-exposing and regrowth process is found to introduce a relatively high potential barrier at the ZnSe/ZnSe homo interface even when the regrowth is undertaken after a slight etching of the first grown epilayer.