Abstract:Alumina nanowires were synthesized on large-area silicon substrate via simple thermal evaporation method of heating a mixture of aluminum and alumina powders without using any catalyst or template. The phase structure and the surface morphology of the as-grown sample were analyzed by X-ray diffractometry(XRD) and scanning electron microscopy(SEM), respectively. The chemical composition and the microstructure of the as-grown alumina nanowires were characterized using transmission electron microscope(TEM). The nanowires are usually straight and the single crystalline has average diameter of 40nm and length of 3-5μm. The growth direction is along the ［002］ direction. Well aligned alumina nanowire arrays were observed on the surface of many large particles. The catalyst-free growth of the alumina nanowires was explained under the framework of a vapor-solid(VS) growth mechanism. This as-synthesized alumina nanowires could find potential applications in the fabrication of nanodevices. 

Key words: alumina nanowires; vapor-solid growth; nanomaterials