Open AccessPressure threshold and dynamics of nucleation for Si nano-crystal grains prepared by pulsed laser ablation
Author(s) -
Deng Ze-Chao,
Qingshan Luo,
Xiaohong Ding,
Lizhi Chu,
W. Y. Liang,
Jinzhong Chen,
Guangsheng Fu,
Yinglong Wang
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.126801
Subject(s) - nucleation , materials science , crystal (programming language) , fluence , laser ablation , scanning electron microscope , raman spectroscopy , nano , supersaturation , raman scattering , laser , molecular physics , analytical chemistry (journal) , optics , composite material , thermodynamics , chemistry , physics , chromatography , computer science , programming language
Si nano-crystal grains are prepared by pulsed laser ablation in low pressure Ar at room temperature through changing the gas pressure and the distance between target and substrate. The morphologies and compositions of samples are characterized by scanning electron microscopy images, Raman scattering spectra and X-ray diffraction spectra.The pressure threshold for Si grain formation is obtained to be 0.6 Pa at a laser fluence of 4 J/cm2, distance between target and substarate of 3 cm, and room temperature.Combining the fluid mechanics model and the nucleation division model, the dynamics process of nucleation is analyzed.The Monte Carlo simulation shows that the nucleation of nano-crystal grains is determined jointly by temperature and supersaturated density.