Evolution of the density of states on going from a two- to a zero-dimensional semiconductorZ. Hens1, B. Grandidier2, D. Deresmes2, G. Allan2, C. Delerue2, D. Stiévenard2 and D. Vanmaekelbergh3
1 Physical Chemistry Laboratory, Ghent University Krijgslaan 281-S12, B-9000 Gent, Belgium
2 IEMN (CNRS, UMR 8520), Département ISEN 41 bd Vauban, 59046, Lille Cédex, France
3 Debye Institute, Utrecht University P.O. Box 80000, 3508 TA Utrecht, The Netherlands
(Received 13 October 2003; accepted in final form 22 January 2004)
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.
73.22.-f - Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals.
73.63.Hs - Quantum wells.
73.63.Kv - Quantum dots.
© EDP Sciences 2004