光致发光谱研究自组织InAs双模量子点态填充

采用固态源分子束外延技术在GaAs(100)衬底上，制备了InAs量子点，对样品进行原子力显微镜测试，统计结果表明量子点尺寸呈双模分布。光致发光谱研究表明，在室温和77 K下，小量子点的发光峰均占主导地位，原因可能是：(1)大量子点的态密度小于小量子点；(2)捕获载流子速率，大量子点小于小量子点；(3)大量子点与盖层存在较大的应变势垒和可能出现的位错和缺陷，导致温度变化引起载流子从小尺寸量子点转移到大尺寸的量子点中概率很小。

Photoluminescence Investigation of InAs Bimodal Self-Assembled Quantum Dots State Filling

Self-assembled InAs quantum dots were prepared on GaAs(100) substrate in a solid source molecular beam epitaxy system. The distribution and topographic images of uncapped dots were studied by atomic force microscope. The statistical result shows that the quantum dots are bimodal distribution. The photoluminescence spectrum results shows that the intensity of small size quantum dots dominated, which may be due to: (1) the state density of large quantum dots lower than that of small quantum dots; (2) the carriers capture rate of large size quantum dots is small relative to that of small ones; (3) there is a large strain barrier between large quantum dots and capping layer, and the large strain is likely to produce the defect and dislocation, resulting in a probability of carriers transferring from large quantum dots to small dots that is very small with temperature increasing.