A mixture of Sn, In, and Ge powders was thermally evaporated to synthesize SnO2 whiskers. Elevation of the growth temperature from 800 degrees C to 900 degrees C contributed to the generation of mixture-phased particles at the tips of whickers, due to the change of the dominant growth mechanism from base-growth vapor-liquid-solid (VLS) to a tip-growth VLS process. We observed that the particles were comprised of a mixture of tetragonal SnO2, rhomboheclral In2O3, and hexagonal GeO2. The composite materials exhibited stable and reproducible sensing properties with respect to NO2 and CO. (C) 2011 Elsevier B.V. All rights reserved.