Low-noise visible-blind photodetectors based on SrTiO_3 single crystal with transparent indium tin oxide electrode as window

Abstract

We fabricate low-noise visible-blind ultraviolet photodetectors of indium tin oxide/SrTiO3/Ag (ITO/STO/Ag) based on the properties of STO bandgap excitation and the conductance of ITO thin film. The ITO films are epitaxially grown on STO wafers as electrodes and windows of the photodetectors, simultaneously. The photodetectors have low noise and very good electromagnetic shielding. The dark current is as low as 270 pA even at a 200 V bias. The peak responsivity reaches to 30 mA/W at the wavelength of 360 nm. From the experimental results, the same ideas can be generalized to develop visible-blind and solar-blind UV photodetectors based on wide bandgap materials, such as LaAlO3, LiNbO3, LiTaO3, BaTiO3, ZnO, MgO, and ZrO2.