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Structural phase transition is often expected when crystalline substrates with high mechanical strength are processed by diamond abrasion at nanoscale. The structural evolution and formation of 3 C-SiC substrates abraded by diamond were explored using molecular dynamics simulation. The evoluted structures were derived by analyzing bond length, bond angle and coordination changes of SiC and diamond abrasives before and after nano-abrasion. Our simulation results explicitly elucidate the stable, graphene-like two-dimensional (2D) structural evolution and formation from SiC and diamond crystalline. This generolized finding of 2D structural formation from three-dimensional (3D) materials in nano-abrasion may shed light on developing new preparation options to make graphene-like 2D-SiC, which is predicted to be a chemically and mechanically stable semicondcuting material with oustanding opto-electro properties. [ABSTRACT FROM AUTHOR]

Abstract: AFM is a powerful and versatile tool which has the ability to fabricate nanoelectronics and other nanoparts using nano-scratching method. To achieve a deeper understanding on AFM-based nano-scratching process, molecular dynamic (MD) simulation approach is employed. Interactive forces between a rigid pyramidal tool simulating an AFM diamond tip and a copper sample are modeled by the Morse function. Two adjacent scratching tests are carried out at different feeds simulating the multiple scratching tests. Effects of the feed on the scratching process are discussed. Results show that the feed has a significant effect on the deformation of the machined surface, the scratching depth, scratching forces and potential energy. The important effect of the relax process in the MD simulation of AFM-based multiple nano-scratching processes is exhibited, which cannot be ignored when analyzing the variation of the potential energy. [Copyright &y& Elsevier]

Experiment and molecular dynamics simulation results of ultraviolet nanosecond laser micromachining of monocrystalline diamond demonstrate the formation of fruitful highly ordered graphite layer between top amorphous layer and bottom diamond, with visible boundaries among them. [Display omitted] • UV ns laser ablation mechanisms of monocrystalline diamond is explored. • Crack-free precise microgroove is fabricated on monocrystalline diamond. • Formation of highly oriented graphite layer in ablated diamond is discovered. • Laser fluence has a strong influence on diamond-to-graphite transformation. Inducing highly oriented graphite layer as buried conductive media in diamond by laser ablation is crucial for promoting the electronic functionalities of structured monocrystalline diamond. In the present work, we fabricate surface microgrooves with high precision and limited heat affected zone on monocrystalline diamond by low cost ultraviolet nanosecond pulsed laser micromachining. In particular, fruitful highly oriented graphite layer is formed between top transformed amorphous layer and bottom pristine diamond, with visible regular boundaries among them. Raman spectroscopy and high-resolution transmission electron microscopy characterization are jointly utilized to identify the phase transformation-induced microstructure evolution in subsurface of ablated diamond. Furthermore, molecular dynamics simulations are performed to elucidate the underlying ablation mechanisms, as well as predict the dynamic ablation process of nanosecond pulsed laser micromachining of diamond. Finally, the effect of laser fluence on the machined surface morphology and the phase transformation characteristics of the ablated diamond is addressed. [ABSTRACT FROM AUTHOR]