PATTERNED GROWTH OF Si NANOWIRES: A COMPARATIVE STUDY OF VLS AND SLS (original) (raw)
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Silicon nanowires (whiskers) have been grown on Si(111) via the vapor–liquid–solid (VLS) reaction using silane as the Si source gas and Au as the mediating solvent. The silane partial pressure and temperature ranges were 0.01–1 Torr and 320–600 °C, respectively. Growth at high partial pressure and low temperature leads to the growth of Si nanowires as thin as 10 nm. These wires are single crystals but exhibit growth defects such as bending and kinking. Lowering the silane partial pressure leads to an increase in the wire width and a reduction in the tendency to form growth defects. At low pressure, 40–100 nm wide well-formed wires have been grown at 520 °C. The VLS reaction using silane allows the growth of Si wires, which are significantly thinner than those grown previously using SiCl4.
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One-dimensional nanostructures such as semiconductor nanowires (NWs) are attractive building blocks due to their promising physical properties and potential as active materials in future electronic and optoelectronic applications. The Crystal growth of nanowires occurs mainly at the interfaces between the growing crystals and the supply media. This article reports on the silicon nanowires grown using a vapor-liquid-solid (VLS) concept. One of the key advantages and the beauty of VLS is that controlled placement or templating of the seed metal produces consequently templated NW growth. This templating is highly required for direct integration of NWs into nanodevices for various smart applications, including sensors, actuators, thermoelectricity generation and photovoltaics. We discuss the major questions related to the discovery of fundamentally new phenomena versus performance benchmarking for many of the Si-NWs applications. Finally we attempt to look into the future and discuss our opinion regarding the upcoming trends in NW research.