Sub-wavelength grating based resonance enhanced ultraviolet light detector and preparation method thereof

The invention provides a sub-wavelength grating based resonance enhanced ultraviolet light detector and a preparation method thereof. The ultraviolet light detector includes a substrate, a sub-wavelength grating layer and an epitaxial layer. The epitaxial layer is provided with n-type contact electrode and a p-type contact electrode. The patterns of the sub-wavelength grating layer are periodical or non-periodical grating patterns. By utilizing a characteristic of high refractive index of sapphire material, the sub-wavelength grating having high nano-scale refractivity and compatible to CMOS technique is obtained. High quantum efficiency is achieved in a wide spectrum range. By utilizing a broadband spectrum light reflex characteristic of sub-wavelength grating, incoming light is reflected by the sub-wavelength grating after passing through an absorption area and then passes through the device absorption area again, so that absorption is enhanced and device quantum efficiency is improved. At the same time, a