Regensburg 2025 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 8: 2D Semiconductors and van der Waals Heterostructures II
HL 8.1: Talk
Monday, March 17, 2025, 15:00–15:15, H15
atomic and electronic structures of colloidal ultrathin PbSe nanoplatelets — •huu thoai ngo1,2, leon biesterfeld3, ahmed addad1, bruno grandidier1, christophe deere1, jannika lauth3, and louis biadala1 — 1Université de Lille, CNRS, Centrale Lille, Université Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520-IEMN, INRAE, UMR-8207, UMET- Unité Matériaux et Transformations, F-59000 Lille, France. — 2Solid Surface Analysis, Institute of Physics, Chemnitz University of Technology, 09126 Chemnitz, Germany. — 3Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3A, D-30167 Hannover, Germany
Two-dimensional (2D) PbSe nanoplatelets (NPLs) are promising materials for lighting technologies due to their efficient and tunable photoluminescence (PL), such as narrow PL emission reaching telecom bands. However, the electronic properties of single NPLs remain underexplored, limiting insights into quantum confinement effects. Here, we investigate the structural and electronic properties of ultrathin PbSe NPLs using low-temperature scanning tunneling microscopy (LT-STM). STM images confirm flat 2D morphologies at various thicknesses while tunneling spectra reveal pronounced quantum confinement along the thickness, resulting in bandgap shifts. High-angle annular dark-field scanning transmission electron microscopy confirms the rock-salt crystal structure, providing atomic-level insights. Additionally, tight-binding calculations demonstrate lateral quantum confinement effects, showing that in-plane dimensions influence electronic properties.
Keywords: Colloidal semiconductor Nanoplatelets; Quantum confinement effect; Low-temperature scanning tunneling microscopy; photoluminescence emission; Two-dimensional (2D) materials