Design of High-Performance UV-Visible Broadband Photodetector Using Cd-Doped ZnO/ZnO Thin-Film Heterostructure

Cd (3%)-doped ZnO TF/ZnO TF heterostructure (HS) was fabricated and studied for UV-Visible broadband photodetection application. X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) images confirmed the structural and morphological integrity of the HS. The HS showed better device performance both in UV and visible regions when compared with a reference ZnO TF sample. Enhancement in absorption intensity due to replacement of Zn ions by larger Cd ions and large photocurrent generation due to increase in carrier concentration via doping can be credited for the improved performance of the hybrid HS. Thus, achieving high spectral responsivity, R $_{\lambda }$ [20.5 A/W (UV), 18 A/W (visible)] and fast photoresponse [ ${T}_{\text {rise}} =0.31$ s, ${T}_{\text {fall}} =0.53$ s (UV) and ${T}_{\text {rise}} =0.27$ s, ${T}_{\text {fall}} =0.29$ s (visible)] from the hybrid sample.