Improved performance of a back-illuminated GaN-based metal-semiconductor-metal ultraviolet photodetector by in-situ modification of one-dimensional ZnO nanorods on its screw dislocations

It is a critical challenge to realize efficient GaN-based UV photodetectors (UV-PDs) due to the existence of high-density dislocations in the epilayers prepared by heteroepitaxy. In this paper, the method of in-situ modifying the screw dislocations in GaN-based materials with one-dimensional (1D) ZnO nanorods by screw dislocation-driven self-assembled solution growth is developed to engineer and improve the photoelectric performances of the back-illuminated metal-semiconductor-metal (MSM) structure p-GaN UV-PDs. The results show that the in-situ grown 1D ZnO nanorods on the dislocations plays the roles of passivating the dislocations to suppress the dark current, improving the spectral response intensity and extending the spectral response band of the MSM structure UV-PDs. The in-situ modification of 1D ZnO nanomaterials can be developed into a method to engineer and modify the defects viz. threading dislocations of the GaN-based semiconductors so as to achieve the purpose of regulating the performance of the related optoelectronic devices, which can be extended to other material systems of optoelectronic devices. (C) 2018 Elsevier B.V. All rights reserved.