Photoconductive gain in solar-blind ultraviolet photodetector based on Mg0.52Zn0.48O thin film

An ultraviolet photodetector was fabricated on MgZnO thin film grown by metal-organic chemical vapor deposition. The peak response of the device centers at 238 nm and cutoff wavelength is 253 nm. The peak responsivity is 129 mA/W at 15V bias, and the UV/visible reject ratio is 4 orders of magnitude. Internal gain is due to the hole trapping at interface that brings low response speed. Native defects at the Au/MgZnO interface degrade the barrier effect, which caused large dark current and high visible response. (C) 2011 American Institute of Physics. [doi:10.1063/1.3670334]