Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski-Krastanov quantum dots.
Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski-Krastanov quantum dots.
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DOI：
10.1038/s41377-021-00564-z
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发表时间：
2021-06-15
期刊：
影响因子：
--
通讯作者：
Koenraad PM
中科院分区：
文献类型：
--
作者：
Gajjela RSR;Hendriks AL;Douglas JO;Sala EM;Steindl P;Klenovský P;Bagot PAJ;Moody MP;Bimberg D;Koenraad PM
利用横截面扫描隧道显微镜(X-STM)和原子探针层析技术(APT)研究了金属-有机气相外延生长(InGa)(AsSb)/GaP STranski-Krastanov量子点(QD)及其在QD-Flash存储器中的潜在应用。X-STM和APT的结合是研究具有原子分辨率的半导体异质结的一种非常有效的方法，它提供了关于该系统的详细的结构和成分信息。较小的量子点呈截锥形，顶面很小，出现在密度很高的∼4 × 10 11 cm−2样品中。APT实验表明，量子点是富In和Sb的。利用X-STM的结构数据进行了有限元模拟，计算了解理表面的晶格常数和向外弛豫。通过结合X-STM和有限元模拟的结果来估计量子点的组成，得到∼InxGa1 − xAs1 − ySby，其中x = 0.2 5-0.30和y = 0.10-0.15。值得注意的是，报道的组成与APT的实验结果以及之前对该材料体系进行的光学、电学和理论分析都是一致的。这证实了参与量子点形成的InGaSb层和GaAs层发生了强烈的混合。对量子点覆盖层的详细分析表明，Sb和In从量子点层中分离出来，APT和X-STM都表明Sb主要存在于量子点之外，证明Sb在量子点形成过程中主要起到表面活性剂的作用。我们的结构和成分分析提供了对这一新的量子点系统的有价值的见解，并为进一步的生长优化以改善QD-Flash存储器件的存储时间提供了一条途径。
We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memories by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). The combination of X-STM and APT is a very powerful approach to study semiconductor heterostructures with atomic resolution, which provides detailed structural and compositional information on the system. The rather small QDs are found to be of truncated pyramid shape with a very small top facet and occur in our sample with a very high density of ∼4 × 1011 cm−2. APT experiments revealed that the QDs are GaAs rich with smaller amounts of In and Sb. Finite element (FE) simulations are performed using structural data from X-STM to calculate the lattice constant and the outward relaxation of the cleaved surface. The composition of the QDs is estimated by combining the results from X-STM and the FE simulations, yielding ∼InxGa1 − xAs1 − ySby, where x = 0.25–0.30 and y = 0.10–0.15. Noticeably, the reported composition is in good agreement with the experimental results obtained by APT, previous optical, electrical, and theoretical analysis carried out on this material system. This confirms that the InGaSb and GaAs layers involved in the QD formation have strongly intermixed. A detailed analysis of the QD capping layer shows the segregation of Sb and In from the QD layer, where both APT and X-STM show that the Sb mainly resides outside the QDs proving that Sb has mainly acted as a surfactant during the dot formation. Our structural and compositional analysis provides a valuable insight into this novel QD system and a path for further growth optimization to improve the storage time of the QD-Flash memory devices.
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影响因子：
4
作者：
Gaan, S.;He, Guowei;Towe, E.
通讯作者：
Towe, E.
影响因子：
8.6
作者：
FEENSTRA, RM;STROSCIO, JA;FEIN, AP
通讯作者：
FEIN, AP
DOI：
10.1109/2944.605656
发表时间：
1997-04-01
影响因子：
4.9
作者：
Bimberg, D;Kirstaedter, N;Ustinov, VM
通讯作者：
Ustinov, VM
影响因子：
3.7
作者：
EBERT, P;HEINRICH, M;LAGALLY, MG
通讯作者：
LAGALLY, MG
影响因子：
4
作者：
Bocquel, J.;Giddings, A. D.;Koenraad, P. M.
通讯作者：
Koenraad, P. M.