摘要
用喇曼光谱研究了Ge_xSi_(1-x)/Si(x=0.5)应变层超晶格的折迭纵声学声子.在Ge_xSi_(1-x)和Si的层厚分别为50和250A的样品中,我们首次观察到了多达9级的折迭纵声学声子模.与理论计算比较,鉴认了不同波矢值的声学声子模.理论与实验结果间符合得相当的好.它表明 Rytov模型对长周期 Ge_xSi_(1-x)/Si 超晶格可以较好地得到应用.
The Raman spectrum due to the folded longitudinal acoustic (FLA) phonons in theGe_x Si_(1-x)/Si (x=0.5)superlattices has been performed. We observed for the first time moreup to the 9th FLA mode in the sample constituted by Ge_xSi_(1-x) with the layer thicknessd_1=50 A and Si with the layer thickness d_2=250 A. The observed acoustic modes of variouswavevectors were identified by means of comparing with thoretical calculation. The strikingcoincidence between thoretical and experimental results indicate that Rytov model is favou-rable for the large-period Ge_xSi_(1-x)/Si superlattices.
基金
国家自然科学基金
中国科学院半导体超晶格国家重点实验室资助
