Hexagonal
boron nitride crystalline film with a thickness of 70
μm is deposited on a c-plane sapphire at 1700 °C by the
chemical vapor deposition (CVD) method. In X-ray diffraction (XRD)
characterizations, a peak of (002) is observed at 26.01° with
the full width at half-maximum (FWHM) of 1.17°, and the c-axis
lattice constant is estimated to be 6.84 Å. The characterization
results of Raman and X-ray photoelectron spectroscopy further confirm
the film’s high quality. Based on the h-BN film, a vacuum ultraviolet
(VUV) photodetector is further fabricated with a responsivity of 48.7
μA/W, exhibiting a photo-to-dark current ratio (PDCR) of more
than 103 as well as an excellent spectral selectivity to
short-wave ultraviolet irradiation. By analyzing the photoresponse
process, the influence of different response mechanisms is explained,
implying the photodetector’s ability to respond quickly.