Interesting electronic and catalytic properties of two-dimensional MoS2 few-layers have recently attracted the attention of researchers. In this paper, the synthesis of MoS2 nanoflakes standing on the SiO2/Si substrate in the process of rapid sulfidation by CHEMICAL VAPOR DEPOSITION has been reported. Material characterization was performed using Raman spectroscopy, XRD and FESEM. The XRD results indicate the dominant phase of 2H-MoS2 and the distance between the two leading peaks of E 1 2g and A1g in the Raman dispersion confirms the thickness of 6 to 10 atomic layers. According to the experimental data, the growth mechanism was introduced based on the nucleation and the growth of two-dimensional islands. In the next stage, it was based on the coalescence of these two-dimensional islands, and in the final stage, it was based on the growth of standing nanoflakes. These structures, which have active sites on the edges, have many potential and promising applications in fine transistors, gas sensors and catalytic reactions.

In this research, aligned carbon nanotubes were grown using a CHEMICAL VAPOR DEPOSITION (CVD) method on both a silicon substrate and on a silicon substrate coated by Fe-Mo nanoparticles. Acetylene gas (C2H2) as the carbon source, argon (Ar) as the carrier gas, hydrogen (H2) for reduction of the nanoparticles and iron-molybdenum nanoparticles as the catalyst source for the growth of carbon nanotubes were used at temperature of 750oC. The reaction was performed inside a tube furnace equipped with a quartz tube and gases were injected with a certain flow rate into the reaction tube. The catalyst Fe-Mo nanoparticles were produced using a CHEMICAL thermal decomposition. Then a silicon substrate was coated with a thin layer of iron-molybdenum nanoparticles by a soakage method. Also, aligned carbon nanotubes were grown on Fe nanoparticles using a VAPOR phase growth method. The samples’ characterization was performed using a scanning electron microscopy (SEM. Leo 906E), field effect scanning electron microscopy (FESEM Mira3 TESCAN) and EDX analysis. Also, Raman spectroscopy was employed to confirm the formation of single walled carbon nanotubes.

In present work, carbon nanotubes (CNTs) were synthesized via CHEMICAL VAPOR DEPOSITION (CVD). Scanning electron microscope (SEM) was applied to investigate the morphology. The microstructure of the CNTs products were further observed by transmission electron microscope (TEM). As the results, CHEMICAL VAPOR DEPOSITION is an extremely versatile technique for the production of carbon nanotubes. This chapter has shown that by controlling the catalyst and synthesis conditions, one can control many aspect of the growth, such as the structure, diameter, length and alignment. The CVD technique can be adapted for mass production purposes or for the controlled growth of nanotubes at particular sites on a substrate for various applications.

Large area fabrication of graphene, as a leading two-dimensional material as well as an allotrope of carbon, is a challenging requirement prior to its preparation for applications. CHEMICAL VAPOR DEPOSITION (CVD) is one of the most effective and promising methods for high-scale and high-quality synthesis of graphene. In this study, graphene layers were grown on copper (Cu) sheets using low-pressure CVD technique at 930 °C, 870 °C, and 760 °C. Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Optical Microscopy (OM) and Atomic Force Microscopy (AFM) were employed in this study to investigate the effect of the process temperature on the structural properties, morphology, grain boundaries, continuity, purity, and number of layers. The results from analyses revealed that at higher temperatures, the continuity and quality of the layers and number of grain boundaries were higher and lower, respectively. In contrast, at lower temperatures, the nucleation and discontinuity of the deposited layers were relatively high. The surface roughness of the graphene sheets increased with a decrease in temperature.

Monolayer WS2 offers great promise for use in optical devices due to its direct bandgap and high photoluminescence intensity. In this way, large-area and high-quality materials are essential for the implementation of technological applications. In this research, we Synthesize the WS2 monolayer under controlled temperature conditions and characterize the films using Fourier-transform infrared spectroscopy (FTIR), Raman, x-ray photoelectron spectroscopies, and scanning electron microscope (SEM). The results show that with the introduction of argon gas as a carrier, the quality of the layer improves, and the growth level of WS2 increases, and as a result, the films show an average coating thickness of 43 nm. By controlling the growth temperature and timely entry of argon-carrying gas, the WO3 precursor is more effectively reduced and the oxidative etching of the synthesized monolayers is protected. The addition of hydrogen more effectively reduces the WO3 precursor and protects against oxidative etching of the synthesized monolayers. The obtained results indicate the complete synthesis of a two-dimensional structure (2D) of a single layer with sheets consisting of a crystal size of about 26 nm with a thickness of about 43 nm.

Carbon nanotubes (CNTs) were grown on nickel catalysts by thermal CHEMICAL VAPOR DEPOSITION (TCVD), using CH4 as precursors, at atmospheric pressure. Ion beam sputtering has been used for Ni DEPOSITION on various silicon substrates. In this study, the effect of oxided silicon surface on the Ni agglomeration and CNTs growth was investigated, using scanning electron microscopy (SEM) and micro-Raman. SEM results show the role of silicon oxide film on the silicon (SiO2/Si), concerning agglomeration of Ni layer and hence, the CNTs growth. The graphite structure of the tubes was confirmed by Raman spectroscopy.

Here, we have synthesized vertically aligned carbon nanotubes (VA-CNTs), using CHEMICAL VAPOR DEPOSITION (CVD) method. Cobalt and ethanol are used as the catalyst and the carbon source, respectively. The effects of ethanol flow rate, thickness of Co catalyst film, and growth time on the properties of the carbon nanotube growth are investigated. The results show that the flow rate of ethanol and the Co layer thickness play important roles on the length and the degree of alignment of the carbon nanotubes. High density VA-CNTs with forest-like structure are grown at a very low ethanol flow rate of 0. 8 sccm, which is the optimized flow rate in our experiments. Therefore, the cost of synthesizing VA-CNTs is decreased by a low consumption of ethanol and utilizing the cheap CVD synthesis method. High density of small-sized catalyst particles is formed in the Co-catalyst thickness of 1 and 2nm, resulting in the growth of vertically aligned nanotubes. However, increasing the thickness of Co layer to 10 and 16 nm, leads to the growth of nanotubes parallel to the substrate with the spaghetti-like structure. The experiments reveal that enhancing the growth time from 5 to 120 min can mostly affect the uniformity and length of VA-CNTs.