Fabrication of hexagonal microstructure on gallium nitride films by wet etching assisted femtosecond laser ablation

Abstract

Nitride-based microstructures are highly desirable for next-generation photonic and micro-electronic technologies. However, the efficient realization of regular microstructures for gallium nitride (GaN) is still technically challenging. This paper demonstrates the formation of hexagonal microstructures on GaN films via femtosecond laser ablation and wet chemical (hot KOH) etching. The fabricated hexagonal microstructures are shown to undergo anisotropic ablation. The structures with tunable profiles and dimensions are obtained by varying the laser energy and etching time. Additionally, we demonstrate that the microstructures were formed by selectively etching away the laser-irradiated region. This work could lead to a new approach to fabricating nitride-based microstructures using wet etching-assisted ultrafast laser processing technologies.