Heteroepitaxial growth of high Mg-content single-phased W-MgZnO on ZnO matrixes in various nucleation states for solar-blind and visible-blind dual-band UV photodetectors

High Mg-content single-phase wurtzite Mg0.51Zn0.49O (W-Mg0.51Zn0.49O) films were realized by radio frequency (RF) magnetron sputtering technique on quartz (SiO2) substrates. The metal-semiconductor-metal (MSM) solarblind (SB) and visible-blind (VB) dual-band ultraviolet (DB-UV) photodetectors (PDs) were also fabricated based on heteroepitaxial growth of W-Mg0.51Zn0.49O films on ZnO buffer layer (BL) at different nucleation states. Under 270 nm of irradiation, the Au/Mg0.51Zn0.49O/ZnO (30 min) PD exhibited an optimal external quantum efficiency (EQE, 304.4%) and specific detectivity (1012), which indicated that the ZnO BL obtained with a 30 min treatment time was most efficient to improve the detection of SB-UV wavelength. The origin of these results was attributed to the contact area and adhesion strength between MgZnO and ZnO matrices. The results showed a feasible way to obtain high Mg-content wurtzite MgZnO alloys and performance improvement through ZnO BL, which is favorable to the applicability in SB/VB DB-UV PDs.