Laser-Induced Periodic Nanoripples Generation on Gallium Nitride Using Near-infrared Ultrashort Pulsed Laser

Laser-induced periodic surface structure (LIPSS), or nanoripples, is a fascinating laser-induced surface morphology observed on a wide range of solid-state materials, with many potential applications in surface engineering, photonics, and optoelectronic devices. On the specific material of gallium nitride (GaN), the well-known formation mechanism and the potential applications of LIPSS are still being explored. Here, a near-infrared spectra of an ultrashort pulsed laser were used to generate periodic nanostructures with dimensions smaller than the laser wavelength on the surface of a GaN LED. From the result, the LIPSS maintained the direction equivalent to the GaN surface, with periodicity around 140-220 nm perpendicular to <1-100> substrate orientation. Finally, the advances in fabrication of LIPSS are presented as a potential nanograting for increasing the efficiency of LED-based GaN.