Electrical characteristics of Pt Schottky contacts on sulfide-treated n-type ZnO -: art. no. 022101

We have investigated the effect of sulfide treatment on the electrical characteristics of Pt contacts on (000-1) n-type ZnO (similar to5x10(15)cm(-3)) single crystals. The Pt contact on conventionally cleaned ZnO surface shows an ohmic behavior. However, the contact produces a Schottky behavior, when the ZnO surface is etched in a boiling (NH4)(2)S-x solution. Measurements show that the Schottky barrier height, ideality factor, and leakage current at -5 V of the Pt contact on the sulfide-treated ZnO are 0.79 eV, 1.51, and 3.75x10(-10) A, respectively. Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) examinations indicate the formation of ZnS phase at the Pt/ZnO interface. Based on the capacitance-voltage, AES, and XPS results, a possible mechanism for the formation of good Schottky contacts is given. (C) 2005 American Institute of Physics.