Bandgap Engineering of Al x Zn1-x O Deposited by Mist Chemical Vapor Deposition for Photodetector Applications: From UV-A to UV-C

This study investigates metal–semiconductor–metal ultraviolet (UV) photodetectors (PDs) based on Al0.1Zn0.9O, Al0.3Zn0.7O, and Al0.5Zn0.5O deposited using the mist chemical vapor deposition. The material analyses indicate that the higher Al content degrades the crystallinity, reduces oxygen vacancy, and increases the energy bandgap of the AlxZn1-xO. The cutoff wavelengths of Al0.1Zn0.9O-, Al0.3Zn0.7O-, and Al0.5Zn0.5O-based PDs, respectively, are 358, 309, and 269 nm, and each of their maximum responsivity is 342.22, 12.19, and 0.73 A/W. It is worth mentioning that the cutoff wavelengths of Al0.1Zn0.9O-, Al0.3Zn0.7O-, and Al0.5Zn0.5O-based PDs are located in UV-A, UV-B, and UV-C regions. The UV-to-visible rejection ratios for the Al0.1Zn0.9O-, Al0.3Zn0.7O-, and Al0.5Zn0.5O-based PDs are $1.7\times 10^{{4}}$ , $2.3\times 10^{{4}}$ , and $5.7\times 10^{{4}}$ . These results suggest that the bandgap engineering is available for the present AlxZn1-xO thin films, making them suitable to detect deep-UV irradiation.