Self-powered photodetector for ultralow power density UV sensing

Abstract

Ultralow power density UV sensing is crucial to application in military and civilian fields. However, it is still confronted with a low signal-to-noise ratio and long response/recovery time. Here, we report a self-powered photodetector based on the Schottky junction of Au NPs@ZnO NWs, which can detect 325 nm light with the power density of 68 nW/cm2, by using pyro-phototronic effect enhanced by localized surface plasmon resonance (LSPR). Under the illumination of 325 nm with the power density of 68 nW/cm2, responsivity of photodetector dramatically enhances from 0 to 0.485 mA/W after decorating Au NPs, detectivity is boosted from 0 to 27.49 × 1010 Jones. The responsivity and detectivity of self-powered photodetector show significant enhancement of over 3290% and over 3298% under the illumination of 325 nm light with the power density of 170 nW/cm2. The fast recovery ensure detection can be finished within 12 ms. The coupled effect of pyroelectric effect and LSPR provides a guideline to design a high-performance photodetector using other nanomaterials.