Study of the Raman spectrum of nanometer SnO2

The Raman spectra of nanometer-sized particles of SnO2 (3–90 nm) at room temperature are reported. In the Raman spectra of the particles of SnO2, which are quite different from that of single-crystal SnO2, there appear two new characteristic peaks, and their intensities decrease gradually with the increase of crystal size. It is concluded that the new peaks can be explained by the surface phonon modes of nanometer SnO2, consequently there is a relation between the structures of surface layers and bulk. It is believed that it is possible to determine the exact positions of atoms in surface layers of some nanometer crystals from their laser Raman spectra.