Reversible barrier height changes in hydrogen-sensitive Pd/GaN and Pt/GaN diodes

The forward current of Pd/GaN and Pt/GaN Schottky diodes is found to increase significantly upon introduction of H-2 into a N-2 ambient. Analysis of the current-voltage characteristics as a function of temperature showed that the current increase is due to a decrease in effective barrier height through a decrease in metal work function upon absorption of hydrogen. The introduction of 10% H-2 into a N-2 ambient was found to lower the effective barrier height of Pd on GaN by 50similar to70 meV over the temperature range of 298 to similar to423 K and of Pt on GaN by 30similar to60 meV over the range of 443 to similar to473 K. The magnitude of the changes increased with temperature due to the effective cracking of the H-2. The changes in barrier height were completely reversible upon restoration of N-2 ambient. (C) 2003 American Institute of Physics.