离子束溅射自组装Ge/Si量子点生长的演变

摘要

采用离子束溅射技术,通过改变Ge的沉积量,在n型Si（100）衬底上自组装生长了一系列Ge量子点样品.利用AFM和Raman光谱对样品表面形貌和结构进行表征,系统地研究了Ge量子点形貌、密度、尺寸大小以及Ge的结晶性和量子点中组分等随Ge沉积量的演变规律.结果表明：Ge层从二维薄层向三维岛过渡过程中,没有观察到传统的由金字塔形向圆顶形量子点过渡,而是直接呈圆顶形生长;且随着Ge沉积量的增加,量子点密度先增大后减小,Ge的结晶性增强同时Ge/Si互混加剧,量子点中Si的组分增加.%A series of Ge quantum dot samples with different Ge thickness is grown on n-Si（100） substrates by ion beam sputtering. Their morphology and structure are characterizated using AFM and Raman spectra, in which the evolution of the morphology, density, dimension, crystalline, and composition of the Ge quantum dots are discussed in detail. The results show that after the growth mode transiting from 2-D to 3-D, the shape of the Ge quantum dot changes directly into a dome shape and no pyramid dots are observed. Besides, with the increase of the Ge deposition, the density of the quantum dots increases to a maximum and then decreases, the crystalline becomes better, but the Ge/Si alloying processing is enhanced and the Ge composition decreases in quantum dots at the same time.