An alternative route for the synthesis of silicon nanowires via porous anodic alumina masks

Amorphous Si nanowires have been directly synthesized by a thermal processing of Si substrates. This method involves the deposition of an anodic aluminum oxide mask on a crystalline Si (100) substrate. Fe, Au, and Pt thin films with thicknesses of ca. 30 nm deposited on the anodic aluminum oxide-Si substrates have been used as catalysts. During the thermal treatment of the samples, thin films of the metal catalysts are transformed in small nanoparticles incorporated within the pore structure of the anodic aluminum oxide mask, directly in contact with the Si substrate. These homogeneously distributed metal nanoparticles are responsible for the growth of Si nanowires with regular diameter by a simple heating process at 800°C in an Ar-H2 atmosphere and without an additional Si source. The synthesized Si nanowires have been characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and RamanThe authors gratefully recognize the financial support provided by MEC through the grants MAT2006-08158, MAT2007-66476-C02-02, MAT2010-19804 and European Community FP6-029192. Financial supports from US Department of Energy through the Massey Chair project at University of Turabo and from the National Science Foundation through the contract CHE-0959334 are also acknowledged. One of us (TC) thanks the economical support from MICROLAN S.A. The “Servicio Interdepartamental de Investigación (SIdI)” from Universidad Autónoma de Madrid and “Centro de Microscopía Luis Bru” from Universidad Complutense de Madrid are acknowledged for the use of the HRTEM and FESEM facilitie