$193nm$ deep-ultraviolet solar-blind cubic boron nitride based photodetectors

Deep-ultraviolet (DUV) solar-blind photodetectors based on high-quality cubic boron nitride $(cBN)$ films with a metal/semiconductor/metal configuration were fabricated. The design of interdigitated circular electrodes enables high homogeneity of electric field between pads. The DUV photodetectors present a peak responsivity at $180nm$ with a very sharp cutoff wavelength at $193nm$ and a visible rejection ratio (180 versus $250nm$⁠) of more than four orders of magnitude. The characteristics of the photodetectors present extremely low dark current, high breakdown voltage, and high responsivity, suggesting that $cBN$ films are very promising for DUV sensing.