Performance of Metal-Semiconductor-Metal Ultraviolet Photodetectors Based on Sol-Gel Derived MgxZn1-xO Semiconductor Thin Films

In this study, MgxZn1-xO (0≤ x ≤ 0.3) semiconductor thin films and metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors were deposited on alkali-free glass substrates (NEG OA-10) using a sol-gel spin-coating process. The effect of incorporating Mg into ZnO thin films on the structural, electrical, optical, and UV photoresponse properties were investigated and photoconductive UV detectors were realized using ZnO and MgZnO thin films. Experimental results showed that the as-prepared MgZnO thin films had a polycrystalline hexagonal wurtzite phase and exhibited high transparency (≥90.0%) in the visible region. The optical bandgap of MgZnO thin films increased from 3.25 to 3.56 eV and the electrical resistivity of the thin films rose from 6.10×10² to 8.86×10⁴ Ω-cm with increasing Mg content. In addition, We found that the MgZnO photodetectors exhibited better photocurrent generation than the pure ZnO photodetectors and the Mg0.1Zn0.9O device exhibited the highest Ion to Ioff ratio of 2×10³.