Investigation of Bandgap Engineering of Gallium Zinc Oxide-Based Ultraviolet Photodetector by Mist Atmospheric Pressure Chemical Vapor Deposition

This paper presents the Ga
_x
Zn
_1-x
O (x = 0, 0.1, and 0.3)-based photodetectors (PDs) by using mist atmospheric pressure chemical vapor deposition. X-ray diffraction and X-ray photoelectron spectroscopy are used to characterize crystal orientation, chemical qualitative, and quantitative characteristics of the Ga
_x
Zn
_1-x
(x = 0, 0.1, and 0.3) thin films. The photoluminescence is used to observe the near-band-edge emission and trap energy level. Among these three PDs, the Ga
_0.3
Zn
_0.7
O-based PD shows the lowest dark current, smallest noise current, and shortest response time. Furthermore, the Ga
_0.3
Zn
_0.7
O-based PD exhibits higher UV-B to UV-A rejection ratio and higher UV-B to visible rejection ratio. It is found that the cutoff wavelength is tunable by changing Ga contents in Ga
_x
Zn
_1-x
thin films.