Current conduction mechanism of Pt/GaN and Pt/Al0.35Ga0.65N Schottky diodes

Electrical properties of Pt/AlxGa1-xN Schottky diodes and chemical bonding states of AlxGa1-xN surface were examined simultaneously to investigate the change in the current transport mechanisms of the Pt/AlxGa1-xN diodes with increasing Al mole fraction. The Pt/GaN diodes showed electrical properties given by the thermionic-emission theory, while the Pt/Al0.35Ga0.65N showed a nonideal Schottky behavior. The oxygen donors were predominantly incorporated at the surface of AlxGa1-xN with increasing Al mole fraction, causing the surface to be heavily doped n type. Consequently, the current transport in the Pt/Al0.35Ga0.65N diodes was dominated by the field emission of electrons through the Schottky barrier, leading to the nonideal Schottky behavior. (C) 2003 American Institute of Physics.