Molecular dynamics investigation of ultrasonic vibration-assisted polishing process for the alternating surface of Graphene/GaN layered composite

In semiconductor materials research, the integration of graphene (Gr) with gallium nitride (GaN) to create layered composite structures is widely recognized as a promising strategy for enhancing device performance. Nonpolar m-plane 01 1 ‾ 0 () GaN eliminates internal polarization fields and has been demonstrated in high-voltage vertical p-n power diodes. The current research on the ultrasonic vibration-assisted polishing (UVAP) process for GaN and Gr/GaN composite materials mainly focuses on polar surfaces. However, the significant mechanical anisotropy between polar and nonpolar GaN surfaces implies distinct material removal and subsurface damage mechanisms during polishing. This study expands such investigations to the nonpolar alternating surfaces of Gr/GaN layered composites. Through systematic molecular dynamics (MD) simulations, we analyze the effects of different vibration processing conditions and interlayer density of graphene on material removal efficiency and subsurface structural integrity. We propose and computationally validate a frequency spacing matching method intrinsic to the alternating layer structure, which effectively stabilizes fluctuations in tangential force. Collectively, these findings not only address a knowledge gap concerning UVAP at nonpolar Gr/GaN heterojunctions but also introduce a structure-related frequency tuning strategy that may be applicable to other layered semiconductor composites.