Improvement of Pt Schottky contacts to n-type ZnO by KrF excimer laser irradiation

High quality Pt Schottky contact to n-type ZnO was formed using KrF excimer laser. A pulsed laser irradiation of n-type ZnO in O-2 pressure of 0.1 Mtorr, prior to Pt metal deposition, considerably improved the rectifying characteristics. The Schottky barrier heights of 0.73 and 0.85 eV were obtained from the current-voltage (I-V) and capacitance-voltage (C-V) measurements, respectively. The cathodoluminescence and Auger electron spectroscopy results indicated that the improvement in rectifying characteristics can be attributed to a removal of surface carbon and hydrogen contaminants and a reduction of subsurface donorlike point defects by the KrF excimer laser irradiation.