State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510641, P. R. China.
Engineering Research Center on Solid-State Lighting and its Informationisation of Guangdong Province, South China University of Technology, Guangzhou, 510641, P. R. China.
Small. 2016 Aug;12(31):4277-85. doi: 10.1002/smll.201503387. Epub 2016 Jun 27.
The growth process of InAs quantum dots grown on GaAs (511)A substrates has been studied by atomic force microscopy. According to the atomic force microscopy studies for quantum dots grown with varying InAs coverage, a noncoherent nucleation of quantum dots is observed. Moreover, due to the long migration length of In atoms, the Ostwald ripening process is aggravated, resulting in the bad uniformity of InAs quantum dots on GaAs (511)A. In order to improve the uniformity of nucleation, the growth rate is increased. By studying the effects of increased growth rates on the growth of InAs quantum dots, it is found that the uniformity of InAs quantum dots is greatly improved as the growth rates increase to 0.14 ML s(-1) . However, as the growth rates increase further, the uniformity of InAs quantum dots becomes dual-mode, which can be attributed to the competition between Ostwald ripening and strain relaxation processes. The results in this work provide insights regarding the competition between thermal dynamical barriers and the growth kinetics in the growth of InAs quantum dots, and give guidance to improve the size uniformity of InAs quantum dots on (N11)A substrates.
利用原子力显微镜研究了在 GaAs(511)A 衬底上生长的 InAs 量子点的生长过程。根据对具有不同 InAs 覆盖度的量子点生长的原子力显微镜研究，观察到了非相干成核的量子点。此外，由于 In 原子的长迁移长度，Ostwald 熟化过程加剧，导致 GaAs(511)A 上的 InAs 量子点不均匀。为了提高成核的均匀性，提高了生长速率。通过研究增加生长速率对 InAs 量子点生长的影响，发现当生长速率增加到 0.14 ML s(-1)时，InAs 量子点的均匀性得到了极大的改善。然而，随着生长速率的进一步增加，InAs 量子点的均匀性变得双模态，这可以归因于 Ostwald 熟化和应变弛豫过程之间的竞争。这项工作的结果提供了关于在 InAs 量子点生长过程中热动力学势垒和生长动力学之间竞争的深入了解，并为改善 (N11)A 衬底上 InAs 量子点的尺寸均匀性提供了指导。
