Fabrication and Raman Studies of MgO/SnO2 Core-Shell Heteronanowires

We have reported the fabrication of MgO core/SnO2 shell nanowires, by a two-step evaporation process. Thermal annealing induced changes in morphology, in which the nanowire surface became rough by the agglomeration of SnO2 shell layers and its crystallinity was enhanced. It was found that three fundamental modes (475, 634, 772 cm(-1)) and an infrared (IR)-active mode (682 cm(-1)) of rutile SnO2 appeared in the Raman spectrum of MgO core/SnO2 shell nanowires. By thermal annealing, the relative intensity of the A(2u) to the A(1g) line was reduced, presumably due to the disorder or size effects.