纳米粒子与单晶硅表面碰撞的反弹机理研究

应用分子动力学方法模拟了纳米粒子与单晶硅(001)表面碰撞、反弹飞离的现象，分析了粒子的反弹行为、基体弹性形变和塑性形变的原子构型特征，以及碰撞过程的能量转化.碰撞后单晶硅表面形成半球形的小坑，小坑周围的基体原子呈非晶态.碰撞过程中与颗粒相邻的基体原子立即非晶化，在非晶层外面基体以可恢复的(111)［110］滑移结构存储弹性形变能.在射入过程，基体发生压缩弹性形变；颗粒反弹时基体势能振荡下降,交替形成压缩形变构型和拉伸形变构型.射入过程中存贮的压缩弹性形变能的释放为颗粒提供了反弹、飞离的能量. 关键词： 碰撞 纳米粒子 单晶硅表面 分子动力学模拟

Repulsion mechanism of nanoparticle colliding with monocrystalline silicon surface

Molecular dynamics simulation of nanoparticle colliding with monocrystalline silicon surface has been carried out in order to investigate the repulsion behavior of nanoparticles. The dynamical behavior of the nanoparticle, the atomistic structure of elastic and plastic deformation of the substrate, and the transformation of energy during the collision process are analyzed. A hemispherical crater is formed on the Si(001) substrate, and there exists an amorphous layer on the wall of the crater. In the collision process, the atoms of the substrate that lie near the nanoparticles transform to amorphoustate immediately. And the elastic deformation which is characterized by the reversible (111)110] glide structure is produced outside the amorphous layer. During the incidence stage, the substrate undergoes compressed elastic deformation. And during the repulsion stage, the potential energy of the substrate declines oscillatory with compressed elastic deformation and tensed elastic deformation formed alternately. The compressed elastic deformation energy stored in the substrate is transferred to the transnational kinetic energy of the nanoparticle, which forces it back from the surface.