Papers by Keyword: VLS Mechanism

Abstract: This paper mainly represent the simple and effective method to design the chrome mask for patterning the platform for zinc oxide nanowire growth. The most essential aspect that need to be considered in designing the chrome mask is the critical dimension of the mask. Hence, the mask is design by using AutoCAD software to design the desired size and length dimension of the mask. Fabrication and development of zinc oxide consist of a series of major steps. The silicon sample will be initially cleaned, followed by zinc oxide deposition and the zinc oxide nanowire will be growth in vertical direction by using VLS (Vapor-Liquid-Solid) mechanism. The nanowire will be patterned by using the chrome mask which design the platform of the nanowire formation. The initial design of the chrome mask is measured and compared to the fabricated chrome mask to detect the efficiency and the accuracy of the pattern transfer process. Our aim is to develop a comprehensive platform for prominent zinc oxide nanowire growth leading to novel and efficient functional of zinc oxide nanowire devices.

Abstract: In this work we report on the growth and preparation of 3C-SiC(111) material for metal-oxide-semiconductor (MOS) application. In order to achieve reasonable material quality to prepare MOS capacitors several and crucial steps are needed: 1) heteroepitaxial growth of high quality 3C-SiC(111) layer by vapour-liquid-solid mechanism on 6H-SiC(0001) substrate, 2) surface polishing, 3) homoepitaxial re-growth by chemical vapour deposition and 4) use of an advanced oxidation process combining plasma enhanced chemical vapour deposition (PECVD) SiO2 and short post-oxidation steps in wet oxygen. Combining all these processes the interface traps density (Dit)can be drastically decreased down to 1.2  1010 eV-1cm-2 at 0.63 eV below the conduction band. To our knowledge, these values are the best ever reported for SiC material in general and 3C-SiC in particular.

Abstract: In this work we report on 3C-SiC heteroepitaxial growth on 4H-SiC(0001) substrates which were patterned to form mesa structures. Two different deposition techniques were used and compared: vapour-liquid-solid (VLS) mechanism and chemical vapour deposition (CVD). The results in terms of surface morphology evolution and the polytype formation using these growth techniques were studied and compared. It was observed both 4H lateral growth from the mesa sidewalls and 3C enlargement on top of the mesas, the former being faster with CVD and VLS. Only VLS technique allowed elimination of twin boundaries for proper orientation of the mesa sidewalls.

Abstract: Here we describe a simple and effective approach to make silicon-based-nanowires structured materials which can be utilized in a range of high technology electronic devices. The strategy for achieving this objective is to create platforms by lithographic patterning on which the diffusion length of reactive species is controlled during the subsequent heat treatment leading to the growth of aligned and linear nanowires. With this simple and versatile method, a large quantity of nanowires can be readily arranged into interesting configurations. This method is proving very promising for a variety of applications, all of which require considerable selectivity and reproducibility in terms of size, shape and structure, to ensure reliability during their use.

Abstract: The use of Ge very rich Si-Ge liquid phase during the heteroepitaxial growth of 3C-SiC on Si-face, on-axis 6H-SiC(0001) substrate by vapour-liquid-solid mechanism leads to the formation of Ge based precipitates inside the 3C layer. These Ge based features are investigated by TEM and atomic models of the Ge clustering are proposed by means of high resolution TEM image simulation. Conventional TEM shows only a few small precipitates sparsely distributed near the interface, as well as dislocations and stacking faults starting from the interface in an almost regular manner. High resolution TEM shows fine structural imperfections in the form of Guinier Preston zones also near the interface. It is concluded that the high Ge content creates an enlargement of the SiC lattice leading to a misfit with the substrate. This could be the driving force for the formation of all the observed features.

Abstract: Boron carbide nanobelts have been synthesized successfully by carbothermal growth method. Boron oxide, activated carbon, gallium oxide and sodium chloride in the molar ratios of 1: 5: 0.03: 0.2 were used as raw materials. The width and thickness of the nanobelts range from 1 to 10 μm, and 80 to 150 nm respectively. The length is up to 50–200 μm. Diffraction peaks in the XRD pattern can be indexed to rhombohedral boron carbide with lattice parameters of a=5.616Å, c=12.067 Å. SAED pattern recorded along [ 010 ] zone axis shows (104 ) growth direction. A vapor–liquid–solid (VLS) growth process on the active catalyst surface is supposed to interpret the growth mechanism of as–synthesized nanobelts.

Abstract: The selective growth of Si column was carried out by depositing Au on patterned Si (111) substrate as a solvent in chemical vapor transport method by using halides (HCl). The Si column was produced by VLS mechanism. The column was covered with SiC by conventional CVD process using HMDS ( Hexamethyldisilane ). Carbon Nano Tube ( CNT ) was deposited on Si column covered with SiC by DC assisted µ-wave plasma CVD.