Effect Of Growth Temperature And Catalyst On The Formation Of One-Dimensional Silicon Nanostructures Via Thermal Evaporation Technique
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Date
2011-03
Authors
Mohd Adnan, Mohd Azam
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
The formation of silicon nanostructures, via thermal evaporation techniques, was studied as a function of annealing temperature and catalyst (Au and AuPd).The silicon powder, serving as the starting source material, was evaporated at a high temperature (900-1100°C) in the flow of argon gas. Grown silicon nanostructures were collected on (111) a silicon substrate surface. The substrate, coated with or without catalyst, was placed at different distances from the source material. By controlling the heating rate, gas flow rate, annealing temperature and time, substrate position, and location, silicon nanostructures can be produced. In this work, the best parameter to produce silicon nanowires is by using a temperature of 1100°C, with a heating rate of 20°C/min, and an Ar flow rate of 100 ml/min. Under these conditions, one dimensional silicon nanostructures will grow on a horizontally-positioned substrate, provided that it is located 6cm from the source material and the time of growth, is 3 hours. Different types of catalyst will affect the morphology of the silicon nanostructures obtained. If an Au catalyst is used, the nanostructures, with diameters ranging between 50 nm to 100 nm, will be obtained. Meanwhile if AuPd is used, a bundle of silicon nanowires, with diameters ranging between 20 nm to 40 nm and a high conductivity of 1.117 x10-4(Ω cm)-1, will be produced. Spherical AuPd at the tip of the structures, with a diameter of 40nm, were also observed. The silicon nanostructure’s growth mechanism is in agreement to the well-known Vapor-Liquid-Solid (VLS) mechanism.
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Keywords
Growth Temperature And Catalyst , Thermal Evaporation