Changes in the electronic energy structure of CdSe nanocrystals of close-packed array by in situ anneal

We synthesized colloidal CdSe nanocrystals through solution process. Nanocrystals showed quantum confinement effects well in solution form. The CdSe nanocrystals coated on Si(1 0 0) wafers were vacuum annealed and analyzed in situ using X-ray absorption and photoelectron spectroscopy to investigate the electronic energy structure of CdSe nanocrystals. As nanocrystalline solids were annealed at high temperature, the absorption edge of CdMlevel and valence band maximum of CdSe decreased as the core level binding energy of Cd 3d. In addition, a red shift with the increase of annealing temperature was also confirmed by the photoluminescence observation of CdSe nanocrystals on glass substrate