SCHOTTKY-BARRIER HEIGHTS OF CONTACT METALS TO P-TYPE ZNSE

Schottky barrier heights (SBHs) of a variety of metals (fn, Cd, Nb, Ti , W, Cu, Ag, Au, Ni, Pt, and Se) contacting to p-ZnSe grown by a molec ular beam epitaxy method were determined by analyzing capacitance-volt age (C-V) and/or current density-voltage (J-V) curves. The SBH values of the Au and Ni contacts were determined from intersections of straig ht lines of the C-2-V curves to be 1.23 and 1.13 eV, respectively. The J-V calculations provided a large SBH value of 1.2 +/- 0.1 eV fora va riety of metals, indicating that the Fermi-level could be pinned at th e contact interface. Reduction of the SBH values to a level lower than 0.4 eV and/or increase of doping concentrations to a level higher tha n 10(20) cm(-3) are essential to obtain an ohmic contact with contact resistivity of around 10(-3) Ohm.cm(2).