Laser ablation has emerged as a novel method to synthesize various nanomaterials.1-3 Currently, most works merely focus on the material synthesis using laser ablation technique with little attention to the relationship between the ablated substrates and the synthesized materials. This work is aimed at filling this gap and giving new insights based on laser ablation of single crystal diamond-cubic (dc) (400) Si in air. Polycrystallization is a ubiquitous phenomenon occurring during laser ablation of Si. The polycrystallization rate of the ablated areas increases with increasing the laser powers, which well explains the polycrystalline instinct of the synthesized nanomaterials. Faster cooling rates of the laser-generated molten Si layers over their nucleation rates result in the surface amorphoization. The molten layers together with the newly formed polycrystalline Si materials will be pushed upward in air by shockwaves to solidify into the amorphous SiOx encapsulated polycrystalline Si composites.
Reference:
1. Zhang, D.; Gökce, B.; Barcikowski, S. Laser Synthesis and Processing of Colloids: Fundamentals and Applications. Chem. Rev. 2017, 117, 3990.
2. Zhang, D.; Liu, J.; Li, P.; Tian, z.; Liang, C. Recent Advances in Surfactant-Free, Surface Charged and Defect-Rich Catalysts Developed by Laser Ablation and Processing in Liquids. ChemNanoMat 2017, DOI:10.1002/cnma.201700079.
3. Zhang, D.; Liu, J.; Liang, C. Perspective on how laser-ablated particles grow in liquids. Sci. China Phys. Mech. Astron. 2017, 60, 074201.
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