Preparation and characterization of rectangular tin dioxide microtubes

Rutile phase SnO2 microtubes were successfully synthesized using a thermal evaporation method at 1550 °C. The products were characterized by X-ray diffraction, scanning electron microscopy and micro-Raman scattering. The microtubes are as long as about 1 mm with almost perfect rectangular cross-section. They possess a large cavity channel of about 30 μm in width and four smooth side surfaces. The side surfaces of SnO2 microtubes are (1 1 0) and (11¯0) planes, while their tube axes are [0 0 1]. The possible formation mechanism of the rectangular SnO2 microtubes is presented.