Influence of the mobility of Pt nanoparticles on the anisotropic etching properties of silicon

Metal-assisted chemical etching (MaCE) has been shown to be a powerful and cost-effective method for surface nano-texturing and silicon micromachining. Since the motion of a metal catalyst during the etching process determines the etched morphology, understanding the mobility of the metal catalysts would enable precise control of the silicon structuring. Through the investigation of Pt nanoparticle (PtNP)-induced etching of silicon, we find that the Schottky barrier height of the metal-Si contacts strongly influences the charge transfer process during the etching. Consequently, the motion of the PtNPs is affected, which is different from previous understandings based on an electrokinetic model.