Metal–Semiconductor–Metal Ultraviolet Photodetectors Based on $\hbox{TiO}_{2}$ Films Deposited by Radio-Frequency Magnetron Sputtering

Metal-semiconductor-metal ultraviolet (UV) photodetectors (PDs) with Au electrodes, based on TiO2 thin films prepared by radio-frequency magnetron sputtering, are fabricated and characterized. The PDs exhibit a low dark current of 9.73 pA at 5-V bias and a high breakdown voltage of over 90 V, owing to the achievement of high-quality stoichiometric TiO2 films. Meanwhile, the high responsivity with a cutoff wavelength at around 380 nm and a large UV-to-visible rejection ratio (310 versus 400 nm) of more than three orders of magnitude are obtained, which suggest that the fabricated PDs are very promising in UV detection applications.