近红外波段InAs量子点结构与光学特性  

Optical Properties and Structure of InAs Quantum Dots in Near-Infrared Band

作　　者：贾国治[1,2,3] 姚江宏[1,2,3] 舒永春[1,2,3] 王占国[1,2,3] 

机构地区：[1]南开大学弱光非线性光子学材料先进技术及制备教育部重点实验室 [2]信息光子材料与技术重点实验室 [3]泰达应用物理学院,天津300457

出　　处：《发光学报》2007年第1期104-108,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(60476042);天津市应用基础研究计划重点项目(06YFJZJC01100);长江学者和创新团队发展计划资助项目~~

摘　　要：采用分子束外延技术,分别在480,520℃的生长温度下,制备了淀积厚度2.7ML的InAs/GaAs量子点。用原子力显微镜对样品进行形貌测试和统计分布。结果表明,在相应的生长温度下,量子点密度分别为8.0×1010,5.0×109cm-2,提高生长温度有利于获得大尺寸的量子点,并且量子点按高度呈双模分布。结合光致发光谱的分析,在480℃的生长条件下,最近邻量子点之间的合并导致了量子点尺寸的双模分布;而在525℃的生长温度下,In偏析和InAs解析是形成双模分布的主要原因。Self-organized semiconductor structures with reduced dimensionality are currently attracting strong interest due to the potential device advantages. The size, distribution and density of quantum dots （QDS） influence on the optical and electrical properties of QDs device. The QDs with bimodal size distribution have been investigated widely due to its some distinctive features compared to the single Gaussian distribution QDs.Thus, it is very important to understand the effects of the growth parameters and mechanisms on the growth of bimodal size distribution QDs. The InAs QDs are grown on the （100） semi-insulating GaAs wafers in Riber32 compact 21 solid source molecular beam epitaxy （MBE） system equipped with a valved cracker cell for arsenic and reflection highenergy electron diffraction （RHEED） for in situ monitoring Of the growth process. Growth temperature is calibrated by infrared pyrometer. First, a GaAs buffer layer with thickness of 100 nm was deposited, and then a single layer of quantum dots was grown by depositing InAs with thickness of 2.7 ML at different growth temperature （520 ℃ or 480 ℃ ）, finaly a 15 nm GaAs cap layer was deposited. The RHEED pattern shows a transformation from streaky to well developed diffraction spots, typical of a three dimensional （3D） growth mode. The same structures without cap layer were grown for atomic force microscopy （AFM） topographic investigation. The measurements of the distribution and topographic images of uncapped dots were taken ex situ by Nanoscope Ⅲ AFM. The photoluminescence （PL） measurements were performed in closed-cycle N2 cryostat under the excitation of 514.5 nm line of an Ar ^＋ laser. Its luminescence spectra were detected with a Fourier transform infrared spectrometer operating with an InGaAs photodetector. Effect of growth temperature on the evolution of bimodal QDs is investigated by combining AFM and PL. The QDs density is significantly reduced from 8.0 × 10^10 cm^-2 to 5.0 × 10^9 cm^-2 as the growth temp

关 键 词：量子点 分子束外延 光致发光 原子力显微镜 

分 类 号：O472.3[理学—半导体物理] O482.31[理学—物理]