n-ZnO nanorods/p-CuSCN heterojunction light-emitting diodes fabricated by electrochemical method

n-ZnO nanorods/p-CuSCN heterojunction light-emitting diodes (LEDs) have been fabricated using low-temperature electrochemical method. The I–V characteristics of the heterojunction LEDs show obvious rectifying behavior. The typical room-temperature electroluminescence spectra obtained from this heterostructure device under forward bias exhibit a strong visible emission across the spectral region from 350 to 600 nm centered at 530 nm. The intensity of the visible emission rises more quickly than that of the ultraviolet emission with the increasing bias. Photocurrent and Raman spectra reveal that the growth process of CuSCN can induce more surface states and defects in the ZnO nanorods, which confirms the enhancement of visible emission from the ZnO nanorods/p-CuSCN heterostructure. Compared with the ZnO-only LEDs, a p-type CuSCN layer used as a hole-transporting material can balance the electrons and holes injection rates in the heterojunction LEDs. The processing procedure in this work is a low-cost, low-temperature and convenient way to fabricate ZnO-based heterojunction light-emitting diodes.