Van Hove Singularities and Trap States in Two-Dimensional CdSe Nanoplatelets

Semiconductor nanoplatelets, which offer a compelling combination of the flatness two-dimensional semiconductors and inherent richness brought about by colloidal nanostructure synthesis, form an ideal general testbed to investigate fundamental physical effects related dimensionality semiconductors. With low temperature scanning tunnelling spectroscopy tight binding calculations, we conduction band density states individual CdSe nanoplatelets. We find occurrence peaks instead typical steplike function associated with quantum well, that rule out free in-plane electron motion, in agreement theoretical states. This finding, along detection deep trap located on edge facets, also restrict provides detailed picture actual lateral confinement wells finite length width.