Pd/GaN Schottky Diode with a Barrier Height of 1.5 eV and a Reasonably Effective Richardson Coefficient

A Schottky diode of high quality Si-doped GaN grown on the c-face of a sapphire substrate by metalorganic chemical vapor deposition was investigated. Using conventional lift-off techniques, Ti/Al and Pd were evaporated as ohmic and Schottky contacts, respectively. The Pd/GaN Schottky diode showed excellent electronic properties. From the temperature dependence of current-voltage characteristics, a barrier height and a measured effective Richardson coefficient were obtained as 1.53 eV and 23.2 A·cm-2·K-2, respectively. The barrier height was much higher than reported values and the measured Richardson coefficient was almost equal to the calculated theoretical value of 26 A·cm-2·K-2.