Enhanced performance of self-powered ultraviolet photodetectors coupled with the photovoltaic-pyroelectric effect based on ZnO/CuBO2 core-shell nanorod arrays

Abstract

An innovative self-powered ultraviolet photodetector based on ZnO/CuBO 2 core-shell nanorod arrays was fabricated using cost-efficient and scalable preparation technologies, including a chemical hydrothermal method and an impregnation technique. The ZnO/CuBO 2 core-shell heterostructure exhibits significant diode behavior with a rectification ratio approaching 7016 at± 1 V because of the type-II band alignment formed at the heterojunction interface, acquiring a maximum responsivity of 165 mA /W1 with an external quantum efficiency of 55.3% (370 nm, 65 mW cm −2 ) and specific detectivity (4.13 ×10 12 cm Hz 1/2 W −1 ) under zero bias. Simultaneously, by applying an external bias to adjust the photovoltaic and pyroelectric effects and delving into the operating mechanisms, the photodetector based on the ZnO/CuBO 2 heterostructure achieves enhanced performance. The decay time has been shortened, and the responsivity has reached up to 38.82 A W −1 (apparent quantum efficiency ~ 13,010%) at − 2.5 V. Moreover, the effects of the power density on the photocurrent response and temperature induced by the photovoltaic-pyroelectric effect are discussed. This study reveals the potential of CuBO 2 (one of the Cu-delafossite families) as a hole transport layer in optoelectronic devices, broadens the application prospects of core-shell nanorod arrays based on the photovoltaic-pyroelectric effect, and provides a direction for modulating the performance of such devices. • CuBO 2 , as a p-type layer of copper delafossite, was firstly used to covered ZnO nanorods forming a core-shell structure. • The facile, convenient and low-cost processes were demonstrated to fabricate original self-powered ZnO NRs/CuBO 2 core-shell heterojunctions. • The performance of the photodetector has been enhanced by modulating photovoltaic and pyroelectric effects. • The curves of output current I pyr+pho , proportion of I pyr and temperature varying with the incident light power densities were fitted with the power-law I&T = AP α . • Significant excellent performance, e.g., R=165 mA W −1 @0 V, 38.82 A W −1 @-2.5 V (370 nm, 65 mW cm −2 ), D* λ =4.13×10 12 cm Hz 1/2 W −1 , RR=7016 at±1 V, was achieved for self-powered ultraviolet photodetectors with ZnO NRs/CuBO 2 core-shell sturcture.