Fricker D, Atkinson P, Jin X, Lepsa M, Zeng Z, Kovács A, Kibkalo L, Dunin-Borkowski R E, Kardynał B E
Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany.
Nanotechnology. 2023 Jan 23;34(14). doi: 10.1088/1361-6528/acabd1.
Self-assembled quantum dots (QDs) based on III-V semiconductors have excellent properties for applications in quantum optics. However, the presence of a 2D wetting layer (WL) which forms during the Stranski-Krastanov growth of QDs can limit their performance. Here, we investigate WL formation during QD growth by the droplet epitaxy technique. We use a combination of photoluminescence excitation spectroscopy, lifetime measurements, and transmission electron microscopy to identify the presence of an InGaAs WL in these droplet epitaxy QDs, even in the absence of distinguishable WL luminescence. We observe that increasing the amount of Ga deposited on a GaAs (100) surface prior to the growth of InGaAs QDs leads to a significant reduction in the emission wavelength of the WL to the point where it can no longer be distinguished from the GaAs acceptor peak emission in photoluminescence measurements. However increasing the amount of Ga deposited does not suppress the formation of a WL under the growth conditions used here.
基于III-V族半导体的自组装量子点在量子光学应用中具有优异的性能。然而，在量子点的斯特兰斯基-克拉斯坦诺夫生长过程中形成的二维润湿层（WL）的存在会限制其性能。在此，我们通过液滴外延技术研究量子点生长过程中润湿层的形成。我们结合光致发光激发光谱、寿命测量和透射电子显微镜来确定这些液滴外延量子点中InGaAs润湿层的存在，即使在没有可区分的润湿层发光的情况下。我们观察到，在生长InGaAs量子点之前，增加沉积在GaAs（100）表面上的Ga的量会导致润湿层的发射波长显著降低，以至于在光致发光测量中它不再能与GaAs受主峰发射区分开来。然而，在此处使用的生长条件下，增加Ga的沉积量并不会抑制润湿层的形成。
