Showing 4 results for Cvd
S. M. M. Shafiei, M. Divandari, S. M. A. Boutorabi, Naghizadeh,
Volume 12, Issue 2 (6-2015)
Abstract
In this work, TiN/TiCN & PN/TiCN multilayer films were deposited by plasma- assisted chemical vapour
deposition (PACVD). Plasma nitriding (PN) and TiN intermediate layer prior to coating leads to appropriate hardness
gradient and it can greatly improve the mechanical properties of the coating. The composition, crystalline structure
and phase of the films were investigated by X-ray diffraction. Atomic force microscopy and scanning electron
microscopy were employed to observe the morphology and structure of the films. The TiCN layer exhibited a columnar
structure. The adhesion force between the film and the tool steel substrate was 30.8 MPa for TiN/TiCN and 25.4 MPa
for PN/TiCN film determined by pull off tests. The hardness of TiN/TiCN film was 12.75 GPa while it was 5.4 GPa for
PN/TiCN film, respectively. The improvement of the adhesion in TiN/TiCN was attributed to a less gradient hardness
configuration. In addition, the mean friction coefficients of the films were about 0.2 for TiN/TiCN and 0.3 for PN/TiCN
film determined by nanoindentation tests.
M. Maleki, S. M. Rozati,
Volume 12, Issue 4 (12-2015)
Abstract
In this paper, polycrystalline pure zinc oxide nano structured thin films were deposited on two kinds of single crystal and polycrystalline of p and n type Si in three different substrate temperatures of 300, 400 and 500◦C by low cost APCVD method. Structural, electrical and optical properties of these thin films were characterized by X ray diffraction, two point probe method and UV visible spectrophotometer respectively. IV measurements of these heterojunctions showed that turn on voltage and series resistance will increase with increasing substrate temperature in polycrystalline Si, while in single crystal Si, turn on voltage will decrease. Although they are acceptable diodes, their efficiency as a heterojunction solar cell are so low
F. Sousani, R. Mozafarinia, A. Eshaghi, H. Jamali,
Volume 15, Issue 1 (3-2018)
Abstract
In this research, Germanium-carbon coatings were deposited on ZnS substrates by plasma enhanced chemical vapor deposition (PECVD) using GeH4 and CH4 precursors. Optical parameters of the Ge1-xCx coating such as refractive index, Absorption coefficient, extinction coefficient and band gap were measured by the Swanepoel method based on the transmittance spectrum. The results showed that the refractive index of the Ge1−xCx coatings at the band of 2 to 2.2 µm decreased from 3.767 to 3.715 and the optical gap increased from 0.66 to 0.72 eV as CH4:GeH4 increases from 10:1 to 20:1.
S. Shanmugan, D. Mutharasu,
Volume 16, Issue 2 (6-2019)
Abstract
Boron included aluminium nitride (B-AlN) thin films were synthesized on silicon (Si) substrates through chemical vapour deposition ( CVD ) at 773 K (500 °C). tert-buthylamine (tBuNH2) solution was used as nitrogen source and delivered through gas bubbler. B-AlN thin films were prepared on Si-100 substrates by varying gas mixture ratio of three precursors. The structural properties of the films were investigated by X-ray diffraction (XRD) technique and verified the formation of polycrystalline and mixed phases of hexagonal (100), & (110) oriented AlN and orthogonal (002) & cubic (333) oriented BN. The crystallite size was smaller and dislocation density was higher as the deposition was conducted with lowest total gas mixture ratio (25 sccm). Improved surface properties were detected for film deposited using lowest total gas mixture ratio and confirmed by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The composition of films showed the existence of higher concentration of B in the film prepared using lower total gas mixture ratio and confirmed by energy dispersive X-ray Spectroscopy (EDX).
