Eur. Phys. J. Appl. Phys. 93, 30405 (2021)
https://doi.org/10.1051/epjap/2021210002

Regular Article

Fabrication and repair of GaN nanorods by plasma etching with self-assembled nickel nanomasks

¹ School of Science, Shandong Jianzhu University, Jinan 250101, P.R. China
² Institute of novel semiconductors, State Key laboratory of Crystal Material, Shandong University, Jinan, 250100, P.R. China
³ School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101, P.R. China

^* e-mail: zhangshiying20@sdjzu.edu.cn; qjxu@sdu.edu.cn

Received: 3 January 2021
Received in final form: 28 January 2021
Accepted: 12 February 2021
Published online: 30 March 2021

Abstract

High crystal quality GaN nanorod arrays were fabricated by inductively coupled plasma (ICP) etching using self-organized nickel (Ni) nano-islands mask on GaN film and subsequent repaired process including annealing in ammonia and KOH etching. The Ni nano-islands have been formed by rapid thermal annealing, whose density, shape, and dimensions were regulated by annealing temperature and Ni layer thickness. The structural and optical properties of the nanorods obtained from GaN epitaxial layers were comparatively studied by high-resolution X-ray diffraction (HRXRD), Raman spectroscopy and photoluminescence (PL). The results indicate that damage induced by plasma can be successfully healed by annealing in NH₃ at 900 °C. The average diameter of the as-etched nanorod was effectively reduced and the plasma etch damage was removed after a wet treatment process in a KOH solution. It was found that the diameter of the GaN nanorod was continuously reduced and the PL intensity first increased, then reduced and finally increased as the KOH etching time sequentially increased.