Photo-detection characteristics of In-Zn-O/SiOx/n-Si hetero-junctions

A layer of indium zinc oxide (IZO) was deposited on the n-type Si substrate clad with a thin thermally grown SiOx layer by pulsed laser deposition to form the semiconductor-insulator-semiconductor (SIS) hetero-junction which exhibits substantial photo-induced responses. Investigation on the IZO layer deposited at various temperatures indicated that IZO film grown at 250 °C possesses a resistivity of 4.9 × 10−4 Ω cm with the transmittance exceeding 80% in the wavelength range between near infrared to ultraviolet light. The photodetection device made of the SIS hetero-junction structure was found to exhibit the photoresponse (R) of 35 AW−1 and 6.15 AW−1 with a quick photo-response time less than 80 ms under the illumination of visible light and ultraviolet light, respectively. The underlying mechanism for such a unique characteristic was attributed to the suppression of majority carrier tunneling resulted from the Schottky barrier established at the SIS interfaces.