ZnO Metal-Semiconductor-Metal Ultraviolet Photodiodes with Au Contacts

epitaxial films were grown on (0001) sapphire substrates by radio-frequency plasma-assisted molecular beam epitaxy. metal-semiconductor-metal ultraviolet photodiodes with various finger widths and pitches ranging from 10 to were also fabricated. It was found that we achieved largest detector responsivity from the photodiodes with finger width and pitch. It was also found that the responsivity increases with the applied bias. With an incident wavelength of and applied bias, it was found that the responsivity for the photodiode was , which corresponds to a quantum efficiency of 44.9%. Furthermore, it was found that noise equivalent power and corresponding detectivity of the photodiodes were and , respectively.