Peric Nemanja, Lambert Yannick, Singh Shalini, Khan Ali Hossain, Franchina Vergel Nathali Alexandra, Deresmes Dominique, Berthe Maxime, Hens Zeger, Moreels Iwan, Delerue Christophe, Grandidier Bruno, Biadala Louis
Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, Junia-ISEN, Centrale Lille, UMR 8520 - IEMN, F-59000 Lille, France.
Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium.
Nano Lett. 2021 Feb 24;21(4):1702-1708. doi: 10.1021/acs.nanolett.0c04509. Epub 2021 Feb 5.
Semiconductor nanoplatelets, which offer a compelling combination of the flatness of two-dimensional semiconductors and the inherent richness brought about by colloidal nanostructure synthesis, form an ideal and general testbed to investigate fundamental physical effects related to the dimensionality of semiconductors. With low temperature scanning tunnelling spectroscopy and tight binding calculations, we investigate the conduction band density of states of individual CdSe nanoplatelets. We find an occurrence of peaks instead of the typical steplike function associated with a quantum well, that rule out a free in-plane electron motion, in agreement with the theoretical density of states. This finding, along with the detection of deep trap states located on the edge facets, which also restrict the electron motion, provides a detailed picture of the actual lateral confinement in quantum wells with finite length and width.
半导体纳米片结合了二维半导体的平面特性以及胶体纳米结构合成所带来的固有丰富性，构成了一个理想且通用的试验平台，用于研究与半导体维度相关的基本物理效应。通过低温扫描隧道光谱和紧束缚计算，我们研究了单个CdSe纳米片的导带态密度。我们发现出现了峰值，而不是与量子阱相关的典型阶梯状函数，这排除了平面内自由电子运动，与理论态密度一致。这一发现，连同对位于边缘小面上的深陷阱态的检测（其也限制了电子运动），提供了具有有限长度和宽度的量子阱中实际横向限制的详细图景。
