Study of Schottky barrier of Ni on p-GaN

The Schottky barrier characteristics of Ni on p-GaN have been investigated using current-voltage-temperature (I-V-T) and capacitance-voltage characteristics (C-V) measurements. Barrier height values ranging from 2.68 to 2.87 eV were obtained from C-V measurements. The temperature dependence of I-V characteristics clearly indicated the dominance of tunneling current in the transport mechanism of the diodes, therefore, barrier height determination using I-V measurements can lead to erroneous results, as indicated by the wide range of barrier heights reported in the literature. Acceptor concentration, deduced from C-V measurements, was found to be of 10(19)/cm(3) within 200 A of the sample surface, and tapered off to be similar to 10(18)/cm(3). These values are 10-100 times higher than the hole concentration of similar to 10(17)/cm(3) obtained from Hall measurements. (C) 2001 American Institute of Physics.