Evolution of the density of states from a two- to a zero-dimensional semiconductor
Résumé
Lead selenide nanocrystals have been electrodeposited on gold(111) with a high degree of control over their dimensions, giving rise to isolated nanocrystals with different edge-to-height aspect ratio. The electron density of states (DOS) of individual nanocrystals as a function of their aspect ratio is studied in the regime of strong quantum confinement by electron tunnelling spectroscopy. We find a broad transition regime, spanning the two- and zero-dimensional geometry, where the DOS function has a rich and variable structure, featuring steps and peaks. The experimental results are supported by electronic-structure calculations.