Homojunction photodiodes based on Sb - doped p -type ZnO for ultraviolet detection

ZnO -based p - n homojunctions were grown using molecular-beam epitaxy. Sb and Ga were used as dopants to achieve the p -type and n -type ZnO , respectively. The mesa devices were fabricated by employing wet etching and standard photolithography techniques. Al ∕ Ti metal was deposited by electron-beam evaporation and annealed to form Ohmic contacts. Current-voltage measurements of the device showed good rectifying behavior, from which a turn-on voltage of about 2 V was obtained. Very good response to ultraviolet light illumination was observed from photocurrent measurements.