Evaluating AlGaN/AlN/GaN heterostructure Schottky barrier heights with flat-band voltage from forward current-voltage characteristics

Both circular and rectangular Ni Schottky contacts on AlGaN/AlN/GaN heterostructures have been fabricated. Both of the Schottky barrier heights were measured by internal photoemission. The flat-band voltage ( V 0 ) for the AlGaN/AlN/GaN heterostructure Schottky contacts was analyzed and obtained from the forward current-voltage (I-V) characteristics. Based on the forward I-V characteristics and with the obtained flat-band voltage, the Schottky barrier heights for the circular and rectangular diodes have been analyzed and calculated by self-consistently solving Schrodinger's and Poisson's equations. The evaluated Schottky barrier heights for the prepared circular and rectangular Ni Schottky diodes agree well with the photocurrent measured results.