Photoluminescence study of self-assembly of heterojunction quantum dots (HeQuaDs)
Photoluminescence study of self-assembly of heterojunction quantum dots (HeQuaDs)
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DOI：
10.1117/12.715304
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发表时间：
2007-02
期刊：
影响因子：
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通讯作者：
K. Eyink;D. Tomich;S. Munshi;B. Ulrich;W. Rice;L. Grazulis;J. Shank;K. Mahalingam
中科院分区：
文献类型：
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作者：
K. Eyink;D. Tomich;S. Munshi;B. Ulrich;W. Rice;L. Grazulis;J. Shank;K. Mahalingam
近年来，量子点已成为人们广泛研究的课题。量子点的独特性质源于其波函数的局域性和相关态密度的奇异性的结合。许多应变的III-V半导体薄膜-衬底系统通过斯特兰基-克拉斯塔诺夫过程的自组装过程形成量子点。导致3D形核的应变释放导致面内晶格常数的变化，从而允许由薄间隔层分隔的后续QD层垂直堆积。最近，这一概念被扩展到允许形成异质结量子点(HeQuaD)。在这种结构中，形成了一个初始的自组装量子点(SAQD)，然后不同的类似应变的材料在初始的SAQD上成核，在下面的量子点上形成了一个冠。这顶王冠的大小也适合引起量子限制。具体地说，已经形成了4层结构的HeQuaD结构，该结构是GaSb冠的InAs SAQD在GaAs上形成的，带有GaAs间隔层。顶端的HeQuads没有封顶，以便进行AFM形态分析。HeQuaD的光致发光在~0.95 eV、1.15 eV和1.35 eV处有三个峰。我们测量了这些光致发光峰的强度和温度依赖性。
Recently quantum dots (QDs) have been the topic of extensive research. Unique properties arise in QDs due to a combination of the localized nature of their wavefunctions and a singularity in the associated density of states. Many strained III-V semiconductor film-substrate systems form QDs via a self-assembly process by means of a Stranski-Krastanov process. The strain relief responsible for the 3D nucleation causes a variation in the in-plane lattice constant which allows subsequent QD layers separated by thin spacer layers to be vertically stacked. Recently this concept has been extended to allow the formation of a heterojunction quantum dot (HeQuaD). In this structure an initial self-assembled QD (SAQD) is formed and then a different similarly strained material is nucleated on the initial SAQDs forming a crown on the underlying QD. This crown is also of a size appropriate to cause quantum confinement. In particular a stack of 4 layers of a HeQuaD structure of a GaSb crowned InAs SAQD on GaAs with GaAs spacer layers has been formed. The top HeQuaDs have been left uncapped to allow AFM analysis of the morphology. Photoluminescence of the HeQuaD has 3 peaks at ~0.95eV, 1.15eV, and 1.35eV. We have measured the intensity and temperature dependence of these PL peaks.