Fabrication of p-type ZnO nanorods/n-GaN film heterojunction ultraviolet light-emitting diodes by aqueous solution method

Zinc oxide (ZnO) is a wide‐bandgap material with excellent optical properties for optoelectronics applications. ZnO nanostructures are attractive for research because it is easy to fabricate in single‐crystalline form and it has interesting physical properties at the nanoscale. In this paper, we report our successful growth of a p‐type ZnO nanorods/n‐GaN film heterojunction ultraviolet light‐emitting diode (LED). The heterojunction LED shows its advantages over a p‐ZnO film/n‐GaN film heterojunction. The LED demonstrates a rectifying I–V characteristics with a turn‐on voltage of 2.7 V. The ideality factor is 6.5. The existences of interface charges in the interface are the reason for this low turn‐on voltage and high ideality factor in the heterojunction. Electroluminescence (EL) spectra of the LED consist of an ultraviolet peak at 378 nm and a broad yellow emission centered at 560 nm. Fitting and comparing EL of the LED with PL of p‐ZnO and n‐GaN show that p‐ZnO contributes more to the EL than n‐GaN.