Papers by Keyword: Atmospheric Pressure Chemical Vapor Deposition

Abstract: Synthesis of high quality graphene films on Cu foil by atmospheric pressure chemical vapor deposition (APCVD) was studied systematically. Acetylene and Cu foil were chosen as the carbon source and the catalyst (or the support) for the synthesis of graphene, respectively. The effect of several synthesized parameters on the structure of graphene films were investigated in detail. The controlled synthesis of graphene and the optimal synthesis conditions were derived. The prepared graphene film was transferred to a coated mirror as a Q-switching saturable absorber used in a Nd:YAG laser. The obtained shortest laser pulse width with single-pulse energy of 8.18 μJ was 242.8 ns. The results indicate that graphene film synthesized by APCVD can be excellently used as saturable absorber material in ultrashort pulse laser.

Abstract: The AZO thin films had been prepared on glass substrates by APCVD process .The transmittance spectra of AZO thin films was measured with S-600 UV-Vis spectrophotometer . The visible light transmittance values of AZO thin films are about 85% and the thickness of the thin films well-distributed by the transmittance spectra of AZO films. Using the envelope method, the film thickness d is calculated about 964.43nm and the discrepancy is only 0.56% compared with the result of instrument measurements. The curve about the refractive index n with the incident wavelength is consistent with the reported literature results. The envelope method is suitable for the optical constants processing of some similar AZO films where exist weak absorption ranges (T≥0.4).

Abstract: Fluorinated silicon oxide (SiOF) films have been prepared in a conventional atmospheric pressure chemical vapor deposition (APCVD) reactor. APCVD technique utilizes tetraethoxysilane, ozone and hydrofluoric anhydride as gas sources. SiOF films are deposited by changing the temperature of deposit. Substrate holder was maintained in the temperature range of 200 to 275°C. Films were characterized based on the deposition temperature. Chemical bonding structure of the films was evaluated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and ellipsometry techniques. FTIR spectra revealed Si-F bond at about 935 cm-1. Incorporation of fluorine has a minimal contribution in the reduction of refractive index of SiOF films from 1.46 to 1.35.Therefore, the main mechanism responsible for this reduction of refractive index is the porosity generated by incorporation of fluorine atom in the SiOF films. Dielectric constant was reduced from 4.2 corresponding to that of SiO2 films, to the values in the range of 3.18 to 3.6 for SiOF films deposited by APCVD technique.

Abstract: Titanium nitride coatings were prepared on common glass slides using TiCl4 and NH3 by atmospheric pressure chemical vapor deposition. The deposition temperature range from 450-650 °C was applied. X-ray diffraction, scanning electron microscope, energy dispersive X-ray Spectrometer, four-point probe sheet resistance instrument and UV-Vis spectrometer were employed to characterize the obtained coatings. The crystallization and electrical conductivity of the coatings was improved with increasing deposition temperature. The reflectance and transmittance spectra showed all the coatings exhibited solar control performance. The coating prepared at 650 °C presented the optimum solar control performance in the present study.