摘要
采用分子束外延技术在(001)GaAs衬底上生长了多层 InAs量子点,原子力显微镜观测了生长在表面的量子点,用透射电子显微镜观察到五层量子点截面像,傅立叶变换光谱仪测试量子点光致发光谱.原子力显微镜以及透射电镜观察结果表明:第一层量子点为椭圆状;上面四层为透镜状量子点,呈现明显的垂直对准,且量子点的密度下降,大小趋向一致.样品中有些位置不同层的量子点连成一线,其边缘存在应力.由于第一层量子点与其他四层量子点的大小、形状不同,导致量子点光致发光峰的半高宽增加.
InAs quantum dots are prepared by molecular beam epitaxy (MBE) with S-K mode on GaAs (001).The sectional structure of five layers of the InAs quantum dots is observed by TEM, and the shape of the first layer QDs is irregular and mainly oval form, and the other four layers are mainly in the form of lens. The multi-layer QDs are obviously arranged vertically. With increasing InAs quantum dot layers, the number density of the quantum dots of the upper layers is lower than that of the first layer. In the experiment, we observe that the QDs in different layers link as a line in few positions and this may be due to the inter-diffusion between In, Ga caused by the strong stress around these QDs. Observed by AFM, the shape and size of QDs growing on surface is similar to that of the first layer QDs observed by TEM. The FWHM of photoluminescence(PL) peaks becomes large owing to different shape and size between the first layer and the other four layers of QDs.
出处
《武汉大学学报（理学版）》
CAS
CSCD
北大核心
2005年第1期47-50,共4页
Journal of Wuhan University:Natural Science Edition
基金
国家自然科学基金资助项目(90101002)
关键词
量子点
分子束外延
透射电子显微镜
光致发光
quantum dots
molecular beam epitaxy
transmission electron microscopy
photoluminescence
