ZnO MSM photodetectors with Ru contact electrodes

ZnO epitaxial films were grown on sapphire substrates by molecular beam epitaxy. Schottky diodes and metal-semiconductor-metal (MSM) photodetectors with ruthenium (Ru) electrodes were also fabricated. It was found that Schottky barrier height at the Ru/ZnO interface was 0.76 eV. It was also found that we achieved a photocurrent to dark current contrast ratio of 225 from our ZnO MSM photodetectors. Furthermore, it was found that the time constant of our photodetectors was 13 ms with three-order decay exponential function.