Temperature-dependent current-voltage characteristics in ZnO based Schottky diodes

Using current-voltage (I-V) measurements, the temperature-dependent current transport in Ag/Zn-polar ZnO Schottky diodes was investigated. Both the series and shunt resistances of the diode were altered at the different temperatures, which were related to the amount of free carriers and the formation of a vacuum-activated surface conduction path, respectively. The reverse biased current transport was associated with a thermally assisted tunneling field emission of carriers and the Poole-Frenkel effect, for higher and lower voltages, respectively. The average interface state density decreased with increasing temperature, which was due to a result of molecular restructuring and reordering and/or variation of the ideality factor with temperatures across the Ag/ZnO interface.