Title: Laser synthesis route for production of GaN nanocrystals for optical sensor protection

Authors: M.A.A. Bakar; S.M. Mohammad; Z. Yinyuan; S.N.A. Razak; M. Abdullah

Addresses: Institute of Nano Optoelectronics Research and Technology, Universiti Sains Malaysia, 11800, Gelugor, Penang, Malaysia ' Institute of Nano Optoelectronics Research and Technology, Universiti Sains Malaysia, 11800, Gelugor, Penang, Malaysia ' State Key Laboratory of Dynamic Measurement Technology, North University of China, 030051, Taiyuan, Shanxi, China ' Microelectronics and Nanotechnology – Shamsuddin Research Centre, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor, Malaysia ' Institute of Nano Optoelectronics Research and Technology, Universiti Sains Malaysia, 11800, Gelugor, Penang, Malaysia

Abstract: Gallium nitride is a well-known material in optoelectronic field due to its unique structure properties which provide benefit including in optical limiting application. The limitation of optical limiting properties of gallium nitride (GaN) itself could be expanded by introducing a smaller form factor known as nanocrystals to utilises the surface/volume ratio for light interaction. Hence, this study will be using an instant and chemical-free technique of synthesising GaN nanocrystals by using laser ablation. The ablation parameter at varied output energy produces nanocrystals in dimension between 40-60 nm which is observed under HRTEM. The presence of GaN in nanocrystals form also confirmed via energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). UV-Vis spectroscopy shows peak absorption at wavelength of 299 nm and photoluminescence emission peak at 485 which correlated to the GaN nanocrystals itself. The optical limiting properties of the samples are tested under direct laser irradiation and show a reduction in light transmittance from GaN nanocrystals however at slightly different rate for every sample as the input power of incident laser is increased. By further extrapolation, the optical threshold achieved by the GaN nanocrystals is at 857, 707 and 607 mW. This shows that the GaN nanocrystals are successfully synthesised via laser ablation and are a viable candidate for optical limiters material for optoelectronic devices.

Keywords: GaN; gallium nitride; laser ablation; optical limiting.

DOI: 10.1504/IJNT.2024.141757

International Journal of Nanotechnology, 2024 Vol.21 No.4/5, pp.251 - 260

Published online: 01 Oct 2024 *

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