Transport studies of patterned Au/ZnSSe(001) contacts fabricated by molecular beam epitaxy reveal substantial lateral inhomogeneities in the Schottky barrier height. The x-ray photoemission results provide evidence of chemical reactions at a number of preferential, surface sites. Incorporation of ultrathin Zn interlayers between the ZnSe substrate and the Au overlayer decreases the value of the n-type Schottky barrier height from 1.62 to 1.05 eV and eliminates all evidence of lateral inhomogeneities in the barrier height. The interlayer-induced Schottky barrier tunability is found to be primarily limited by Zn-Au alloying within the overlayer. (c) 2006 American Vacuum Society.