Structural and optical study of SnO2 nanobelts and nanowires

A broad band structured in two emissions peaked at about 460 nm and 570 nm is revealed by large area Photoluminescence and Cathodoluminescence. No evidence of near band edge transition is found. Single nanobelt spectroscopy carried out by Cathodoluminescence inside the Scanning Electron Microscope shows that reducing the lateral dimension of the nanobelts from 500 to 50 nm, a blue shift of the main emission band of about 20 nm is found at room temperature. The possible role of Oxygen vacancies and surface / volume ratio on the absence of the near band edge emission and on the blue shift of Cathodoluminescence spectra from single nanocrystals is discussed.