Self-powered NiO/κ-Ga2O3 heterojunction photodiode for fast broadband ultraviolet (UV) radiation detection

A novel broadband p-n UV photodiode is presented, that integrates an ultrawide band gap n-type κ-Ga 2 O 3 epitaxial film doped with silicon (Si) and a p-type NiO polycrystalline film, to provide a planar NiO/κ-Ga 2 O 3 p-n heterojunction for UV detection applications. The proposed device features a circular design, with a diameter of 240 micrometers, resulting in compactness and functionality, and represents the first demonstration of broadband UV detection using planar NiO/κ-Ga 2 O 3 photodiodes. It can be operated in self-powered mode, which allows UV detection without use of an external power supply. The p-n photodiode exhibits excellent sensitivity to UVC light and acceptable sensitivity to UVB and UVA radiations. However, the response to UVA light is still weak and requires further optimization of the diode design. Response and recovery time below 0.8 seconds were observed for all UV illumination range. The presented photodiode has a simple design and shows significant potential in high-performance broadband UV detection in self-powered operation. This figure shows the response of NiO/κ-Ga 2 O 3 photodetector to the UV light stimuli (Abstract Graphic). • NiO/κ-Ga 2 O 3 p-n heterojunction with circular planar geometry is fabricated • First demonstration of broadband UV detection NiO/κ-Ga 2 O 3 photodiodes is presented • The responsivity to UVC was particularly higher compared to UVA and UVB • The photodiode shows fast response, with rise and recovery times of less than 0.8 s