Investigation of the effects of Mg incorporation into solution-processed InZnO semiconductor thin films for UV photodetectors

Abstract

We incorporated Mg into InZnO semiconductor thin films and deposited metal-semiconductor-metal (MSM) ultraviolet photodetectors on alkali-free glasses by sol-gel spin-coating method. In this study, the effect of incorporating Mg into InZnO thin films on the optical, electrical, and UV photoresponse properties were investigated and photoconductive UV detectors were realized using IZO-based thin films. The Mg content ([Mg]/[In +Zn]) was varied from 0 to 20% in the resultant solutions. Each as-coated sol-gel film was preheated at 300 °C for 10 min and then annealed at 450 °C for 2 h. All as-prepared IZO-based thin films were amorphous phase, displayed a flat surface and uniform thickness, and exhibited good visible transmittance (≥ 90.0%). We found that UV illumination increased the photocurrents in all oxide thin films, and that MIZO photodetectors exhibited better photocurrent generation than pure IZO photodetectors. The decrease in oxygen deficiencies and carrier concentration resulted in less electrical trapping in MIZO than in pure IZO photodetectors.