利用Keating模型计算Si(1-x))Gex及非晶硅的拉曼频移

Calculation of Raman shifts of Si_((1-x))Ge_x and amorphous silicon using Keating model

利用Keating模型计算了Si(1-x)Gex合金中Si—Si,Ge—Ge和Si—Ge三种振动模态的拉曼频移,计算分别获得Ge浓度为0.1,0.5和0.9时,Si—Ge的振动拉曼频移分别为402.75,413.39和388.15cm-1,这些结果与文献的实验结果符合,证明了Keating模型建立的关于原子振动模型是有效的,并可以利用拉伸压缩和相邻原子键之间弹性系数变化获得处于应变状态的拉曼光谱频率.利用Keating模型首次计算得到了非晶硅材料的单声子散射峰为477.029cm-1,与文献实验结果480.0cm-1相近,说明了非晶硅中原子的总体效果与晶体硅相比处于拉伸状态.

The Raman shifts of Si—Si,Ge—Ge and Si—Ge in Si_（1-x）Ge_x alloys are calculated by Keating model.The calculated Raman shifts are 402.75,413.39 and 388.15 cm-1 when the concentrations of Ge are 0.1,0.5 and 0.9 respectively.These results are consistent with the reported experimental results,which indicates the validity of the Keating model for obtaining the Raman frequency of strained materials by changing the elastic coefficients of stretching and compression and bond-bending interaction. The single-phonon scattering peak at 477.029 cm-1 in amorphous silicon is obtained for the first time by Keating model, which is in agreement with the result of 480.0 cm-1 from the literature, indicating that the atoms of amorphous silicon as a whole are stretched compared with that of crystalline silicon.