Dopant atom distribution and spatial confinement of conduction electrons in Sb-doped SnO2 nanoparticles -: art. no. 245312

Colloidally prepared nanoparticles of pure and n-type SnO2 were deposited oil Au foils and studied by photoelectron spectroscopy with synchrotron radiation. Substitutional n-type doping was achieved using Sb with an initial oxidation state of III or V in the chemical preparation process. The dopant concentration was 16.7%. Dopant atom distributions in the nanoparticles were found by measuring the intensity ratio of the Sb 3d(3/2) to Sn 3d(3/2) core level photoelectron spectra as a function of the excitation energy, Sb was more evenly distributed through the nanoparticles when its initial oxidation state was Sb-V while some surface enrichment of the dopant resulted for Sb-III doping. High-resolution Sri 3d core level spectra show a plasmon Satellite feature which is due to the excitation of conduction band electrons. These exist as a free electron gas confined to the inner region of the nanoparticles.