High-Sensitivity Mid-Ultraviolet Pt/Mg0.59Zn0.41O Schottky Photodiode on a ZnO Single Crystal Substrate

A Pt/Mg 0.59 Zn 0.41 O Schottky photodiode on a ZnO single crystal is reported. The Mg 0.59 Zn 0.41 O film was deposited on a ZnO single crystal substrate by an RF magnetron sputtering method. The optical bandgap of the Mg 0.59 Zn 0.41 O film obtained from the spectral transmittance and reflectance, was 4.6 eV. The fabricated photodiode consisted of an anti-reflection SiO 2 film, semitransparent Schottky Pt electrode, Mg 0.59 Zn 0.41 O film, n + -ZnO single crystal substrate and Pt/Ti ohmic electrode. The ideality factor of the photodiode, obtained from the current–voltage characteristics, was 1.3. The maximum responsivity was 0.015 A/W at the wavelength of 220 nm.