Structural and electrical properties of heteroepitaxial (111)Fe3O4/(0001)GaN Schottky junction

We investigated the structural and electrical properties of the half-metallic oxide Fe3O4 film grown on an n-type semiconducting gallium nitride GaN. X-ray diffraction and transmission electron microscopy analyses confirmed the heteroepitaxial growth of the (111) Fe3O4 film on (0001) GaN with a clear interface. The current-voltage measurement for the Fe3O4/GaN heterojunction indicated a strong temperature dependence of the Schottky diode behavior. At room temperature, the Fe3O4/GaN heterojunction exhibited a weak diode-like behavior for the bias-voltage sweep. However, as the temperature decreased from room temperature to 30 K, the current in negative-bias voltages decreased significantly, but its change in the positive bias regions was small. Thus, the rectification ratio increased by similar to 10(4) times, while the barrier height decreased and the ideality factor increased. The barrier height inhomogeneities at the interface could be an origin for such distinctive temperature dependences of barrier height and ideality factor.