Hydrogen sensing characteristics of semipolar (11(2)over-bar2)GaN Schottky diodes

Abstract

The hydrogen detection characteristics of semipolard (11 (2) over bar2) plane GaN Schottky diodes were investigated and compared to c-plane Ga- and N-polar and nonpolar a-planed (11 (2) over bar2) GaN diodes. The semipolar GaN diodes showed large current response to 4% hydrogen in nitrogen gas with an accompanying Schottky barrier reduction of 0.53 eV at 25 degrees C, and the devices exhibited full recovery to the initial current level upon switching to a nitrogen ambient. The current-voltage characteristics of the semipolar devices remained rectifying after hydrogen exposure, in sharp contrast to the case of c-plane N-polar GaN. These results show that the surface atom configuration and polarity play a strong role in hydrogen sensing with GaN. (C) 2014 AIP Publishing LLC.