Selective and Gentle Modulation of Multi-Period Sinusoidal Texture on Curved Surface of Diamond-Like Carbon via Cold Atmospheric Plasma Jet

Existing microfabrication processes are generally characterized by unavoidable residues and thermal damage, lack of material selectivity, and limited controllability, which significantly impact the texturing quality of high-performance coatings such as diamond-like carbon (DLC). Hence, this paper reports a maskless modulation strategy for curved surface based on cold atmospheric plasma jet (CAPJ) for gentle and controllable sinusoidal texturing of functional coatings. Through the development of multi-freedom motion and monitoring systems along with the regulation of key process parameters, the consistency and uniformity of graphical modulation on DLC surfaces are greatly enhanced. The surface morphology and composition changes of etched dots, lines, and sinusoidal textures were comprehensively characterized and analyzed at atomic and molecular scales by SEM, SDM, EDS, XPS, XRD, FTIR, profilometer, and Raman spectrometer, demonstrating the exceptional properties of our strategy in terms of selectivity, residue-free, and absence of thermal damage, further achieving high-quality on-demand modulation of standard multi-period sinusoidal profiles with amplitudes as low as 60 nm on curved DLC. The developed novel micro/nanofabrication process holds significant potential for gentle and selective surface treatment in interdisciplinary MEMS devices.