SiC Nanowires : from growth to related devices (original) (raw)

SiC nanowires: material and devices

Journal of Physics D: Applied Physics, 2011

SiC nanowires are of high interest since they combine the physical properties of SiC with those induced by their low dimensionality. For this reason, a large number of scientific studies have been dedicated to their fabrication and characterization as well as to their application in devices. SiC nanowires growth involving different growth mechanisms and configurations was the main theme for the large majority of these studies. Various physical characterization methods have been employed for evaluating SiC nanowire quality. Very low diameter (<10 nm) nanowires as well as nanowires free of planar defects have not been demonstrated and these are some of the main challenges. Another issue is the high unintentional doping of the nanowires that does not allow the demonstration of high performance field effect transistors using SiC nanowires as channel material. On the other hand, the grown nanowires are suitable for field emission applications and to be used as reinforcing material in composite structures as well as for increasing the hydrophobicity of Si surfaces. All these aspects are examined in detail in the different sections of the present paper.

In situ growth of SiC nanowires on RS-SiC substrate(s)

Journal of Crystal Growth, 2004

SiC nanowires over 10 mm in length and 20-100 nm in diameter have been synthesized by a novel in situ chemical vapor growth process on RS-SiC plates. The SiC nanowires were identified as single crystal b-SiC with Si-C chemistry. The growth direction of the nanowires is /1 1 1S. The growth mechanism is discussed and a kinetic vapor-solid growth mechanism is proposed. The process demonstrates the possibility to fabricate SiC nanowires in ceramic matrix composites, such as continuous SiC fibers reinforced SiC matrix composites, with the SiC nanowires uniformly dispersed in the matrix.

Cubic SiC Nanowires: Growth, Characterization and Applications

2010

Functionalized 3C-silicon carbide NW have the potential to act as highly sensitive detector elements in biochemical field (Yakimova et al., 2007). Many methods are currently being used to prepare SiC-NW (pure or with a SiO 2 shell) on silicon substrates using a catalyst, including chemical vapour deposition, vacuum evaporation of SiC, direct synthesis from Si and C powders. In this paper we will present a brief review of growth methods used to obtain cubic silicon carbide NW, both with and without SiO 2 shell, and our results on the NW growth and characterization of morphological, structural and optical properties by SEM, TEM, CL and Raman. Finally we will review some of the possible applications for nanodevices.

Catalyst-Free Chemical Vapor Deposition for Synthesis of SiC Nanowires with Controlled Morphology

Springer Series in Materials Science, 2013

SiC wires of different morphology were grown using methyltrichlorosilane (MTS) and hydrogen by chemical vapor deposition under ambient pressure. Taguchi method has been used to design experiments to get the optimum parameters for growing SiC wires of diameter in nanometer range. Results from XRD and SEM analyses showed the growth of -SiC wires having different morphology. At higher temperature (1500 °C), the growth of SiC grains was observed rather than wires. The optimum deposition conditions for uniform diameter growth of SiC nano wires, smoothness of the surface and homogeneous growth of SiC on the surface have been obtained. The hydrogen to MTS flow rate ratio should be above 20 for the growth of SiC wires of nanometer diameter. The deposition temperature for the growth of crystalline SiC wires should be 1100-1300 °C. The total flow rate of carrier gas comprising of argon and hydrogen for a particular H2/MTS flow rate ratio is critical for morphological outcome of SiC. In the present study it was 2 lpm for H2/MTS flow rate ratio 14 to obtain wire morphology. When the total gas flow rate was increased to 6 lpm for the same H2/MTS flow rate ratio 14, the wire morphology of SiC disappeared and the formation of grains occurred. The optimum deposition temperature i.e. 1300 °C was kept constant and further experiments were conducted by changing H2/MTS mole ratio to verify morphological outcome of SiC. A plausible mechanism has been suggested for the above observations using vapor-solid mechanism. . TEM images of the SiC nanowires grown at H2/MTS = 70 and T = 1300 °C.

Growth of SiC Nanowires on Different Planes of 4H-SiC Substrates

Materials Science Forum, 2012

Growth of SiC nanowires (NWs) on monocrystalline 4H-SiC substrates was conducted to investigate a possibility of NW alignment and polytype control. The growth directions of the NWs on the top surfaces and the vertical sidewalls of 4H-SiC mesas having different crystallographic orientations were investigated. The majority of the NWs crystallize in the 3C polytype with the 111 growth axis. Six orientations of the 3C 111 NWs axis with respect to the substrate were obtained simultaneously when growing on the (0001) plane. In contrast, no more than two NW axis orientations coexisted when growing on a particular mesa sidewall. Growth on a particular {10-10} plane resulted in only one NW axis orientation, giving well-aligned NWs.

From Si nanowire to SiC nanotube

Journal of Nanoparticle Research, 2011

Si nanowires (NWs), with diameters of about 800 nm and lengths of about 10 lm, previously synthesized by the VLS method with gold catalyst, were carburized at 1,100°C under methane for conversion into SiC nanostructures. These experiments have shown that Si NWs have been transformed into SiC nanotubes (NTs) with approximately the same sizes. Nanotubes' sidewall thickness varies from 20 to 150 nm depending on the NTs' height. These SiC nanotubes are hexagonal in shape and polycrystalline. A model of growth based on the outdiffusion of Si through the SiC layer was proposed to explain the transformation from Si nanowires to SiC nanotubes. This model was completed with thermodynamic calculations on the Si-H 2 -CH 4 -O 2 system and with results from complementary experiment using propane precursor. Routes for obtaining crystalline SiC NTs using this reaction are proposed.

Synthesis and characterization of 3C–SiC nanowires

Journal of Non-Crystalline Solids, 2008

Silicon carbide nanowires have been synthesized by carbothermal reduction, from carbon monoxide and single crystal silicon. Transmission electron microscopy and cathodoluminescence studies confirm the growth of a cubic b-SiC core, coated with an amorphous oxide shell. Planar defects, as stacking faults and rotational twins, are present on (1 1 1) planes. The formation of short thick rods or long thin wires, depending on the growth temperature and time, is discussed.

Silicon carbide nanowires synthesis and preliminary investigations

Acta Physica Polonica Series a

As the field of biotechnology expands and the semiconductor industry approaches the limit of size reduction with conventional materials, these and other fields will increasingly rely on nanomaterials with novel properties. Silicon carbide (SiC) possesses many properties that make it appealing to research and industry: a large band gap, high hardness, high strength, low thermal expansion, chemical inertness, etc. It is known that silicon carbide nanowires can be synthesized through a reaction between silicon vapor and multiwalled carbon nanotubes. This process was refined to produce smaller, straighter nanowires. This was done by analyzing the dependence of the reaction rate on the partial vapor pressure of silicon. The reaction rate was studied by comparison of SiC and multiwalled carbon nanotubes peak intensities in X-ray diffractograms, which produced an estimate of the respective reactions' SiC yields. The particle morphologies were then analyzed with transmission electron mi...

A simple approach to polytypes of SiC and its application to nanowires

Thin Solid Films, 2006

SiC polytypes in bulk form and nanowire are systematically investigated using our empirical potential that is based on a simple approach, and which incorporates electrostatic energies due to bond charges and ionic charges. Using the empirical potential, the system energies of 3C (zinc blende), 6H, 4H and 2H (wurtzite) structured SiC in bulk form are calculated and compared with ab initio calculations and experimental results. Our calculated results reveal that 3C -SiC is the most stable while 2H -SiC is unstable among these structures at 0 K. This is consistent with experimental results. The appearance of polytypes in bulk form is qualitatively discussed by considering ionicity of semiconductors based on our simple approach. Furthermore, we clarify the versatility of our simple approach to nanostructures considering SiC nanowire. Hexagonal SiC nanowire stabilizes a 2H structure in the diameter range of D < 20 (nm), whereas 3C -SiC is stabilized only at a large diameter range beyond 20 (nm). This is also consistent with experimental findings for InAs and InP nanowires. SiC polytypes in nanowire are discussed in terms of the ratio of the number of surface dangling bonds to the total number of interatomic bonds. D