Amorphous Indium-Gallium-Oxide UV Photodetectors

We report the fabrication of amorphous (In_xGa_1-x)₂O₃ metal-semiconductor-metal ultraviolet (UV) photodetectors on glass substrate by co-sputtering. It was found that, we could change the cutoff wavelength of the fabricated photodetectors by changing the RF sputtering power of the In₂O₃ target. With 5 V applied bias, it was found that the measured dark currents were 2× 10^-12 , 1× 10^-11 , and 2.3×10^-11 A for sample A prepared with 40 W In₂O₃ sputtering power, sample B prepared with 50 W In₂O₃ sputtering power, and sample C prepared with 60 W In₂O₃ sputtering power, respectively. It was also found that the UV-to-visible rejection ratios were 3× 10³ , 5× 10³ , and 1.5× 10⁴ for samples A, B, and C, respectively. Furthermore, it was found that the response speeds of the fabricated devices were good.