Ultraviolet Light Detection Properties of ZnO/AlN/Si Heterojunction Diodes

High-quality n-ZnO/AlN/p-Si and n-ZnO/p-Si heterojunction diodes were successfully fabricated by RF sputtering deposition technique. XRD, SEM, and EDX measurements confirm the excellent structural and surface morphological attributes of the grown ZnO thin films. I−V measurements were performed and a good rectification ratio of ~ 319 was found for both the diodes. The contrast ratio, being the ratio of current in the UV illumination condition to the current in dark condition, had higher values of ~ 14 for the n-ZnO/p-Si UV detector and ~ 20 for the n-ZnO/AlN/p-Si UV detector at − 5 V. Enhanced performance of the UV detector n-ZnO/p-Si diode due to the use of a buffer layer of aluminum nitride (AlN) between the ZnO and Si, has been found, thus establishing AlN as the material of choice as a buffer layer to improve the UV detection in ZnO/Si-based devices.