Photoelectrochemical reaction and H2 generation at zero bias optimized by carrier concentration of n-type GaN.

The authors studied the photoelectrochemical properties dependent on carrier concentration of n-type GaN. The photocurrent at zero bias became the maximum value at the carrier concentration of 1.7x10(17) cm-3. Using the sample optimized carrier concentration, the authors achieved H2 gas generation at a Pt counterelectrode without extra bias for the first time. The authors also discussed the mechanism of the dependence of photocurrent on the carrier concentration of GaN.