Abstract
The photoelectrochemical and electrical properties of nonpolar (11 (2) over bar0)-oriented and semipolar (11 (2) over bar2)-oriented GaN were compared with those of (0001)-oriented GaN. Flatband potentials were obtained in the order of (11 (2) over bar0) < (0001) < (11 (2) over bar2). The highest photocurrent at a zero bias had been expected for the (11 (2) over bar0) sample considering the flatband potential, but the photocurrent of the (11 (2) over bar0) sample was the lowest among the three. This could have been due to the electric properties of the (11 (2) over bar0) sample used. The surface morphology changes indeed by the photoelectrochemical reactions are also discussed.