Modelling and experimental study of nanomilling 3D nanogrooves on GaSb surfaces

Atomic force microscopy (AFM) tip-based nanofabrication is a simple and feasible method for machining nanostructures. However, existing studies primarily focus on fabricating grooves with constant width and depth, with limited research dedicated to the fabrication of three-dimensional (3D) grooves. In this study, an AFM tip-based nanomilling technique is employed to fabricate 3D nanogrooves on single-crystal gallium antimonide (GaSb), with a focus on investigating the underlying material removal mechanism and subsurface damage. To enable accurate prediction of 3D groove profiles, a theoretical model was established to estimate the machining depth, accounting for variations in the vibration frequency and rotation radius during nanogroove fabrication. By systematically varying key parameters—including vibration frequency, applied load, and rotation radius—their influences on the morphology and quality of the fabricated nanogrooves were comprehensively investigated. Experimental results demonstrated that nanogrooves with well-controlled depth and surface quality could be achieved, particularly under optimized conditions involving higher vibration frequencies and lower applied loads. The analysis of transmission electron microscopy (TEM) indicated that the thickness of the amorphous GaSb layer induced by the machining process decreased with increasing vibration frequency, whereas the dislocation density increased. This increase in dislocation density contributed to work hardening, effectively mitigating subsurface damage. Furthermore, a nanofluidic memristor is prepared based on the machined high-quality 3D nanogrooves. These findings provide important insights into the nanomilling behavior of soft-brittle materials and offer a foundation for the precise and reliable fabrication of high-quality 3D nanogrooves via AFM tip-based techniques.