A HIGH-RESOLUTION ELECTRON-MICROSCOPY STUDY OF VANADIUM DEPOSITED ON THE BASAL-PLANE OF SAPPHIRE

The interface between vanadium and the basal plane of sapphire was studied by conventional and cross sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface. A 50 nm thick vanadium film was deposited on the (0001) basal plane of sapphire by molecular beam epitaxy (MBE). The TEM observations of the interface were made from three directions: two cross-sectional views (parallel to [$($) over bar$$ 1210](Al2O3) and [$($) over bar$$ 1010](Al2O3)) and plan view (parallel to [0001](Al2O3)). From the SADP, the following orientation relationship was obtained: (111)(V) parallel to(0001)(Al2O3); [$$($) over bar 101](V) parallel to[$($) over bar$$ 1210](Al2O3). Cross-sectional HREM observations showed the atomic configuration at the interface, and the existence of periodic arrays of geometrical misfit dislocations. Computer simulations show that sapphire is aluminum-terminated at the interface with vanadium.