Ultraviolet fast-response photoelectric effects in LiTaO₃ single crystal

The photoelectric effects of LiTaO₃ (LTO) single crystals are experimentally studied with two kinds of LTO wafers, 10° tilted and untilted, at room temperature. A transient open-circuit photoelectrical response of 143 ps rise time is observed in the 10° tilted LTO when a 266 nm pulsed laser with a duration of 25 ps is irradiated directly onto the LTO surface. The untilted LTO with interdigitated electrodes of 10 μm finger width and 10 μm interspacing exhibits a linear dependence on the applied bias and power density of incident light, a response peak at about 235 nm and a sharp cutoff at about 270 nm. The noise current is only 61 pA at 20 V bias under the illumination of sunlight outdoors at midday. The experimental results suggest the promising application of the LTO single crystal in UV detection, in particular, as a solar-blind fast-response photodetector.