Chiral ZnO-CuO Nanorod Arrays for Circularly Polarized Photodetection

Circularly polarized light (CPL) photodetectors have attracted widespread interest from both the academic and industrial communities. Commonly, the key function layer of a film structured CPL photodetector is the chiral material layer that exhibits optoelectronic response differently to the left-handed and right-handed circularly polarized light. In this report, the heterostructured chiral ZnO-CuO nanorod arrays were successfully prepared by a strategy of combining the solution synthesis of ZnO nanorod arrays, grazing angle magnetron sputtering of Cu, and a thermal oxidation process. The chirality of left-/right-handedness was controlled by the sputtering angles and rotating direction. The morphology of nanorod arrays benefits light scattering and hence the absorption. The band structure of the ZnO-CuO heterojunction facilitates carrier transfer and transport. The CPL photodetectors based on the chiral ZnO-CuO nanorod arrays exhibit good performance with a responsivity (R), photocurrent asymmetry factor (gIph), responsivity asymmetry factor (gres), and photodetectivity (D*) of 13.0 mA/W, 0.038, 0.22, and 8.3 × 1011 Jones achieved, respectively, under the 450 nm circular polarized light.