Solar-Blind Photoresistors Based on $hbox{Mg}_{0.48} hbox{Zn}_{0.52}hbox{O}$ Thin Films Grown on $rhbox{-Al}_{2} hbox{O}_{3}$ Substrates by Radio-Frequency Plasma-Assisted Molecular Beam Epitaxy

摘要

Solar-blind photoresistors based on $hbox{Mg}_{0.48}hbox{Zn}_{0.52} hbox{O}$ thin films were fabricated on $r$-plane sapphire substrates by radio-frequency plasma-assisted molecular beam epitaxy. High-quality $a$-plane-orientation single-phase wurtzite $hbox{Mg}_{0.48}hbox{Zn}_{0.52}hbox{O}$ thin films are demonstrated by X-ray diffraction and absorption spectra. The MgZnO photoresistors exhibit a large dark/photoresistance ratio up to $hbox{1.7} times hbox{10}^{4}$ with the light intensity of 0.61 $hbox{mW/cm}^{2}$ at 260 nm. The spectral response shows a sharp response peak only in the solar-blind region with maximum responsivity of $hbox{1.5} times hbox{10}^{-3} Omega^{-1}cdothbox{W}^{-1}$ .