Ultrafast 0D/1D ZnO/CuO photodetector in nanosecond scale by engineering the type-II heterostructure

Abstract

Zero-dimensional/one-dimensional (0D/1D) heterojunctions have excellent potential in the field of optoelectronic devices due to the synergy effect of different dimensions. Most reported 0D/1D heterojunction photodetectors only focus on optimizing the separation efficiency of photogenerated carriers at the interface. However, the carriers within the quantum dots (QDs) cannot be transferred to the electrodes, resulting in recombination of photogenerated carriers separated at the interface. Therefore, the response speed of most 0D/1D heterojunction photodetectors is still limited to the order of seconds (s) and milliseconds (ms). In our work, we demonstrate a nanosecond (ns) scale ZnO/CuO heterojunction photodetector with efficient photoelectric conversion by engineering the type-II 0D/1D heterojunction interface. Herein, the surface defect states of ZnO QDs are deliberately introduced as “electrons storage pool” to suppress carrier recombination and further promote separation, which has been confirmed by photoluminescence (PL) and time-resolved photoluminescence (TRPL). As a result, the photodetector exhibited excellent performance with ultrafast response speed of 20 ns, responsivity of 213 A/W, and detectivity of 2.95 × 1011 Jones, respectively. This defect related interface engineering provides a feasible strategy for the development of high-performance 0D/1D heterojunction photodetectors.