Solar Blind Photodetectors Enabled by Nanotextured β-Ga2O3 Films Grown via Oxidation of GaAs Substrates
D. Patil-Chaudhari, M. Ombaba, J. Y. Oh, H. Mao, K. H. Montgomery, A. Lange, S. Mahajan, J. M. Woodall, and M. S. Islam
IEEE Photonics Journal, April 2017.
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A simple and inexpensive method for growing Ga2O3 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-Ga2O3. The β-Ga2O3 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-Ga2O3 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.
Gallium arsenide, beta-gallium oxide, argon, dark current, energy-dispersive x-ray spectroscopy