Papers by Keyword: Vapor-Liquid-Solid Growth

Abstract: Undoped and B-doped silicon-based nanowires (SiNWs) were synthesized by vapor-liquid-solid growth, and SiNW devices using Au electrodes were prototyped using focused ion beam (FIB) processing. Needle-shaped thin SiNWs were formed at a substrate temperature between 1170 and 1313 °C. The average and minimum diameters of the B-doped SiNWs were 72 nm and 52 nm, respectively. According to the current-voltage characteristics, SiNW devices have ohmic properties, and the estimated resistivity of the undoped and B-doped SiNWs are about 3.8 × 10³ Ωcm and 1.7 × 10³ Ωcm, respectively.

Abstract: Silicon-based nanowires (Si-NWs) were fabricated by vapor liquid solid (VLS) growth, and Si-NW device was prototyped using focused ion beam (FIB) processing. The needle shaped thin Si-NWs were formed at a substrate temperature between 1120 and 1313°C. The average and minimum diameters of the NWs were confirmed 60 nm and 44 nm, respectively. As the double-layered structure was observed in the NWs by transmission electron microscope images, it is possible that those are silicon-based NWs with Si core and SiO₂ shell structure. From current-voltage characteristics, the Si-NW device has a semiconducting property, and the estimated resistivity of the Si-NW is about 3.1 x 10⁴ Ωcm.

Abstract: . Zinc Oxide nanowires (ZnO-NWs) were grown by vapor-liquid-solid (VLS) through chemical vapor deposition (CVD) with Au/Pd nanoparticles (Au/Pd-NPs) as catalyst. (Au/Pd)-NPs of 5 nm were synthesized by inert gas condensation technique (IGC), deposited on silicon substrates and characterized by atomic force microscopy (AFM). The substrate with the catalytic seeds was introduced in the reaction system where the ZnO-NWs were grown under different conditions such as: system pressure, position of the substrates with respect to the precursor material source, growth time and temperature. The nanostructures obtained were characterized by scanning electron microscopy (SEM), energy dispersed x-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The growth parameters and the effect of catalyst nanoparticles coalescence on the ZnO-NWs dimensions is also discussed in this work.

Abstract: The present chapter deals with the difficult task of giving a brief survey of the synthetic routes employed to prepare materials with characteristic features on the nanometer scale. Definitions and general concepts regarding nanostructured and nanometer-sized materials are shortly tackled in the introductory part, which is followed by an overview of the most important approaches developed to synthesize such materials. No attempt is made to create a comprehensive and detailed synopsis of the experimental methods currently available. Rather, attention is focused on a selected number of general methodologies, the choice of which can be usually motivated by a mix of historical perspective, scientific significance and technological potential. So-called “top-down” approaches are discussed first, whereas the second part of the chapter is devoted to “bottom-up” ones. The former group includes mechanical processing, melt quenching, and de-vitrification methods. Sonochemistry, pulsed laser ablation, wet chemical synthesis, sol-gel processing, microwave processing, spray pyrolysis, flame synthesis, inert gas condensation, vapor deposition, and vapor-liquid-solid growth form instead the latter group.

Abstract: Epitaxial growth of cubic silicon carbide on 6H-SiC substrates, and 6H-SiC substrates with (111) 3C-SiC buffer layer, deposited by vapour liquid solid mechanism, was compared. The morphological details of the grown layers were studied by optical microscopy and their microstructure by transmission electron microscopy. The influence of the substrate on the nucleation of 3C-SiC, the initial homoepitaxial 6H-SiC nucleation before 3C-SiC as well as the formation of defects, are discussed.

Abstract: We report the results of a systematic investigation performed to reduce the residual n-type doping level of the 3C-SiC layers grown by the VLS mechanism on 6H-SiC(0001) on-axis substrate. This new approach, termed “High purity VLS” leads to low doped and low compensated material, which was confirmed by Raman and Low Temperature Photoluminescence spectroscopy. The resultant 3C morphology remains typical of single-domain layers and the n-type doping level could be estimated around 6x1016 cm-3.

Abstract: Despite outstanding properties, the development of 3C-SiC electronics is still suffering from the lack of bulk 3C-SiC substrates. Up to now, there is no real seed and optimized growth processes for this material. We address in this work the bulk growth of 3C-SiC by a two-step-liquid phase approach. By coupling experiments with global process simulation, we address the problems that must be overcome to consider the solution growth technique as a possible approach for the growth of bulk 3C-SiC.

Abstract: We attempted the vapor–liquid–solid (VLS) growth of SiC film in Si-Li solution using gaseous CH4 as a carbon source at 900 oC. A 100-m-thick liquid-phase epitaxy (LPE) layer was obtained on a 4H-SiC (0001) substrate under CH4 pressure of 0.9 MPa. X-ray diffraction (XRD) and a high-resolution transmission electron microscope (HR-TEM) measurement showed that the LPE layer was single-phase 2H-SiC. We concluded that VLS growth in Si-Li solution using gaseous CH4 as a carbon source is useful for growing single-phase 2H-SiC.