VLS growth of silicon nanowires in cold wall Cat-CVD chamber

Growth of silicon nanowires by Vapour-Liquid-Solid (VLS) method has been studied in a cold wall Catalytic Chemical Vapour Deposition (Cat-CVD) chamber. It has been found that the instrument can be used in two modes, Hot Wire Chemical Vapour Deposition (HWCVD) and Chemical Vapour Deposition (CVD). These modes are tested with two methods for the preparation of the catalyst nanoparticles, namely thermal annealing of catalyst thin film and chemical attachment of catalyst nanoparticles. Growth in HWCVD mode is faster but the nanowires have deformities like conical shape, short length and uncatalyzed silicon deposition on the substrate. Using the CVD mode with modified process parameters solves these problems. The resultant silicon nanowires are characterized by Scanning Electron Microscopy, Energy-dispersive X-ray spectroscopy and Transmission Electron Microscopy.