Solar Blind Photodetectors Enabled by Nanotextured β-Ga2O3 Films Grown via Oxidation of GaAs Substrates

A simple and inexpensive method for growing Ga
₂
O
₃
using GaAs wafers is demonstrated. Si-doped GaAs wafers are heated to 1050 °C in a horizontal tube furnace in both argon and air ambients in order to convert their surfaces to β-Ga
₂
O
₃
. The β-Ga
₂
O
₃
films are characterized using scanning electron micrograph, energy-dispersive X-ray spectroscopy, and X-ray diffraction. They are also used to fabricate solar blind photodetectors. The devices, which had nanotextured surfaces, exhibited a high sensitivity to ultraviolet (UV) illumination due in part to large surface areas. Furthermore, the films have coherent interfaces with the substrate, which leads to a robust device with high resistance to thermo-mechanical stress. The photoconductance of the β-Ga
₂
O
₃
films is found to increase by more than three orders of magnitude under 270 nm ultraviolet illumination with respect to the dark current. The fabricated device shows a responsivity of ~292 mA/W at this wavelength.