Improved Photoresponse Performance of Self-Powered β-Ga₂O₃/NiO Heterojunction UV Photodetector by Surface Plasmonic Effect of Pt Nanoparticles

Solar-blind photodetectors have received increasing attention due to their widely applications in military and civil aspects. However, most of the photodetectors exhibit low detection ability for weak ultraviolet light signal, and the forewarning of weak ultraviolet radiation is important for the immune system of humans. Herein, the self-powered photodetector based on β-Ga ₂ O ₃ /NiO heterojunction with an ultralow dark current (1.09 nA at -15 V) has been fabricated, and the synthesized platinum (Pt) nanoparticles (NPs) are used for surface modification of the device. The obtained devices with Pt NPs exhibit a large I _photo /I _dark ratio of 9153, an excellent detectivity of 4.2 x 10 ⁹ Jones, an ultrahigh linear dynamic range of 79 dB, and a high responsivity of 4.27 mA/W, with respective enhancements over 4476%, 2220%, 71.7%, and 2442% compared to the pristine device, respectively. These results indicated that the device has the excellent ability for weak ultraviolet light signal detection, and the enhanced performance can be attributed to the Pt NPs, which can remarkably enhance the generation of photogenerated carriers via the formation of the local electric field and the local surface plasmon resonance effect. The experiment provides an effective method for fabricating high-performance solar-blind photodetector.