Aluminum-catalyzed epitaxial growth of silicon nanowire (SiNW) arrays was performed on Si wafer by chemical vapor deposition at 600°C. The arrays showed a low optical total reflectance in the visible light spectrum, with a minimum of 2% around 450nm wavelength. Following SiNW growth, dry etching of the Al catalyst was performed in situ using HCl chemistry at 600°C. The effectiveness of aluminum etching was assessed by energy dispersive X-ray spectroscopy, by high resolution transmission electron microscopy and by a controlled growth experiment. This SiNW array growth and subsequent catalyst dry etching opens up the possibility of an all in vacuum fabrication process of radial junction solar cells. Al catalyst dry etching following growth using HCl gas at 600°C. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.