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区别于传统的尺寸模型,本研究基于唯象声子受限理论,综合考虑声子波矢q,标准偏差σ,介质受限系数β三者的统一,建立相应的函数关系,着重探讨了非晶包覆硅纳米晶因尺寸效应引起的拉曼频移和非对称性宽化.结果表明,随着硅纳米晶尺寸减小到玻尔半径以下,布里渊区内波矢由准连续转变为离散形式参与散射,此离散波矢能更准确地拟合小尺寸硅纳米晶的拉曼谱线;进一步改变标准偏差a,精细化调整拉曼谱峰的非对称性.受限系数p则影响了非晶介质的受限势垒高度对峰位频移,尺寸越小,影响越大.最后,本研究建立的理论模型与课题组实验结果、文献数据进行比较,发现综合考虑三者的协同效应有助于更准确地评估非晶包覆型硅纳米晶的尺寸效应、纳米晶的存在形态及其相对比例.“,”Different from the traditional size model,this research is based on the phenomenological phonon confinement model to analyze the size effect of Si nanocrystals,considering phonon wave vector q,standard deviation a and confinement coefficient β and their relative functional relationship comprehensively.The discussions focused on the Raman shift and asymmetry broadening of Si nanocrystals embedded in amorphous SiC.The results show that as the size of the Si nanocrystals decreased to below Bohr radius,the q can change from quasi-continuous form to discrete form participating the scattering,and so this discrete q can more accurately fit the Raman spectral lines of small-sized Si nanocrystals.Standard deviation a can further precisely adjust the asymmetry of Raman peaks,and the smaller the size,the greater the impact.The confinement coefficient β involves the influence of the limitation barrier height to the Raman shift.Finally,the theoretical model was compared with our experimental results and literature data.It can be found that the comprehensive consideration of the synergistic effect of the q,a and f3 should be conducive to evaluating the size effect,crystal morphology and relative proportion of amorphous coated Si nanocrystals.