Amorphous boron nitride for vacuum-ultraviolet photodetection

摘要

Boron nitride (BN) has attracted substantial attention in the fields of vacuum-ultraviolet (VUV) photodetection owing to its ultra-wide bandgap and high optical absorption coefficient. However, in practical application, boron nitride crystals cannot satisfy current requirements in size and quality. In this work, we prepared an amorphous sp~2 bonding BN film by magnetron sputtering with boron as the growth source at a low temperature (500°C). No harsh conditions of high temperature and pressure are required, but the purity and uniformity of the film can be ensured by this method. Based on such a film, a VUV photodetector (PD) with metal-semiconductor-metal (MSM) structure is further constructed, which exhibits an extremely low dark current (～10~(-14) A), a high photo-to-dark ratio (～10~3), and an excellent spectrum selectivity of VUV band. The improvement of PD's performance benefits from the pure and compact composition of the grown BN film. These results indicate that the growing amorphous BN film at a low temperature by reactive magnetron sputtering is a feasible method for preparing high-performance BN VUV photodetectors.