采用间歇式As中断方法利用分子束外延(MBE)生长了不同厚度的InGaAs量子点,并通过反射式高能电子衍射仪(RHEED)以及扫描隧道显微镜(STM)对其表面进行形貌表征与分析.研究发现间歇式As中断方法有利于改善量子点的均匀性,同时量子点的表面形貌特征由生长温度和沉积厚度决定;量子点沉积厚度越大,量子点面密度越高;在一定生长温度范围内,生长温度越高量子点分布均匀性越强,反之则越弱;研究还发现InGaAs量子点的生长过程中存在3个截然不同的阶段和两种明显的生长模式转变点,3个阶段分别是层状生长阶段、量子点形成阶段和量子点自合并成熟阶段,两种生长模式转变点分别是SK转变和量子点自合并熟化转变.
Different thickness of InGaAs quantum dots were prepared through intermittent interruption growth(IIG) of As resource in molecular beam epitaxy (MBE) and the morphologies of them were studied and analyzed by reflection high energy electron diffraction (RHEED) and scanning tunneling microscopy (STM).The results show that the uniformity of quantum dots was improved under intermittent interrupt growth and the morphologies of quantum dots were controlled by the growth temperature and the amount of material deposited.A larger amount of material deposited could lead to higher density and more uniformity of quantum dots could be attained at higher growth temperature in a special range.There were three obvious differences phases such as layer-by-layer growth, formation and self-ripen phases of quantum dot and two transition points which were Stranski-Krastanow (SK) and self-ripen transition in the process of growth of InGaAs quantum dots.
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