High-performance visible blind ultraviolet photodetector based on KTaO₃ single crystal

We report a visible-blind ultraviolet photoconductive detector with interdigitated electrodes based on KTaO₃ (KTO) single crystals. Both the steady spectral responses and the transient photovoltaic measurements clearly exhibit a cutoff wavelength at 344 nm (∼3.6  eV), in accordance with the bandgap of KTO. The KTO photodetectors show a low dark current ∼1.5  pA at 20 V, and a high UV-to-visible rejection ratio with 3 orders of magnitude at room temperature. The quantum efficiency is 37.49% under 20 V bias, and the detectivity D^* of 3.85×10¹²  cm·Hz^0.5/W, which is comparable to that of silicon photodetectors in the UV region. The rise time of photoelectric response is ∼260  ps, indicating an ultrafast photoelectric response characteristic. The present work offers appealing prospects for the application of KTO materials in high-performance visible blind ultraviolet photodetectors.