The Effect of Substrate Type on SiC Nanowire Orientation

Abstract

beta-SiC nanowires were synthesized on different monocrystalline substrates: Si (001), Si (111), 3C-SiC (001), 4H-SiC (0001), 6H-SiC (0001). The SiC nanowire growth was carried out using a Chemical Vapor Deposition method, with silane and propane diluted in hydrogen (3%) as precursors. The deposition was performed at atmospheric pressure and at 1100 degrees C, after dewetting of the Ni catalyst, which had been previously evaporated onto the substrate, to induce 1D growth according to a VLS process. The crystal structure of the nanowires, as determined by X-ray diffraction and High Resolution Transmission Electron Microscopy, corresponds to 3C-SiC polytype growing along a (111) direction, irrespective of the substrate. The occurrence of (111) stacking faults was observed, partly reduced for samples grown on 3C-SiC substrate. The growth on (111) substrate allowed to achieve a good vertical alignment of the nanowires, as investigated by Scanning Electron Microscopy. High Angle Annular Dark Field imaging and Energy Dispersive X-Ray spectroscopy were performed to study the catalyst particle on top of the wires and showed the formation of a nickel-silicon alloy.

Demonstration of Hexagonal Phase Silicon Carbide Nanowire Arrays with Vertical Alignment

“…We propose that the low carbon solubility and diffusion through the catalytic Ni 2 Si clusters affords the large degree of supersaturation necessary for the growth of hexagonal polytype. In our high-supersaturated system, the low growth rates likely arise from the effects of lower growth temperature (compared to 1100 °C and higher 12,28 ) combined with low carbon solubility within the nickel silicide catalyst, both of which would promote a lower precursor diffusion rate within the catalyst, relative to the rate expected within a liquid catalyst.…”

A silicon carbide nanowire field effect transistor for DNA detection

“…Semiconductor NWs are generally synthesized via a vaporliquid-solid (VLS) process [32]. In this study, SiC NWs are grown by VLS on (100) oriented Si substrate in a home-made induction-heated vapor phase epitaxy (VPE) reactor at atmospheric pressure, using diluted (3%) propane and silane as precursors, purified Pd H 2 as a carrier gas, and Ni as a catalyst [33]. The Si substrate is first etched with hydrofluoric acid to remove the native oxide and then coated with a 2 nm thick nickel layer by e-beam evaporation.…”

Silicon Carbide Nanowire Devices for Label-Free Electrical DNA Detection

“…The NWFETs used for the FET fabrication are fabricated using 3C-SiC nanowires prepared by Vapor Phase Epitaxy [7]. The nanowire length ranges from 5 to 10 µm for a diameter between 20 and 50 nm.…”