scholarly journals Nanostructural, Chemical, and Mechanical Features of nc-Si:H Films Prepared by PECVD

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Jong-Ick Son ◽  
Hee-Jong Nam ◽  
Nam-Hee Cho
Keyword(s):  
Film Thickness ◽  
Vapor Deposition ◽  
Deposition Time ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Relative Volume ◽  
Relative Volume Fraction ◽  
The Mean ◽  
Si Films ◽  
Si Nanocrystallites

This study examined the effects of film thickness on the nanostructural, chemical, and mechanical features of nc-Si:H films deposited by plasma-enhanced chemical vapor deposition. SiH4and H2were used as the source gases, and the deposition time was varied from 10 to 360 min. The mean nanocrystallites size in the Si films increased from~6 to~8 nm with increasing film thickness from 85 to 4150 nm. Moreover, the nanocrystallite concentration and elastic modulus increased from~7.5 to~45% and from 135 to 147 Gpa, respectively. In the 4150 nm thick film, the relative volume fraction of Si nanocrystallites and relative fraction of Si–H bonds in the films were approximately~45% and~74.5%, respectively.

scholarly journals Photocatalytic Activity of Hierarchically Structured TiO2Films Synthesized by Chemical Vapor Deposition

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Heon Lee ◽  
Sung Hoon Park ◽  
Young-Kwon Park ◽  
Sun-Jae Kim ◽  
Byung-Hoon Kim ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Chemical Vapor Deposition ◽  
Film Thickness ◽  
Hierarchical Structure ◽  
Vapor Deposition ◽  
Deposition Time ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Hierarchically structured TiO2photocatalyst films were synthesized using low-pressure metal-organic chemical vapor deposition (LPMOCVD) method to examine their photocatalytic activity. The thickness of the TiO2films increased proportionally with increasing deposition time. The TiO2film synthesized at 773 K showed a hierarchical structure composed of vertically grown laminar (112)-oriented anatase crystals. With increasing deposition time, the grain became larger and the morphology became sharper. In the initial CVD stage, small particular crystals were formed, above which sequential growth of layers of columnars with increasing size took place, forming hierarchical structure. The hierarchically structured TiO2film exhibited much higher photocatalytic activity than unhierarchically structured TiO2film. The photocatalytic activity increased with increasing film thickness.

The Effect of DC Bias Voltage on the Structural and Optical Properties of Hydrogenated Nanocrystalline Si Thin Films

2007 ◽  
Vol 124-126 ◽  
pp. 1261-1264 ◽  
Author(s):  
Jae Hyun Shim ◽  
Nam Hee Cho
Keyword(s):  
Vapor Deposition ◽  
Amorphous Matrix ◽  
Chemical Vapor ◽  
Rf Power ◽  
Structural And Optical Properties ◽  
Dc Bias ◽  
Pl Emission ◽  
Si Films ◽  
Si Nanocrystallites ◽  
Nanocrystalline Si

Amorphous and nanocrystalline Si films were prepared by plasma enhanced chemical vapor deposition (PECVD). The films were deposited with a RF power of 100 W, while substrates were under DC biases varying from 0 to -600 V. The size as well as the concentration of Si nanocrystallites increased with raising the DC bias; the PL emission wavelength was shifted from 400 to 750 nm. A model for the nanostructural variation in the nc-Si:H films was suggested to describe the change in the size and concentration of the nanocrystallites as well as the amorphous matrix depending on the DC bias conditions.

Crystal structure and microstructure of epitaxial Pb(Zr,Ti)O3 films consisting of mixed phases with tetragonal and rhombohedral symmetries grown on (100)cSrRuO3//(100)SrTiO3 substrate by metalorganic chemical vapor deposition

2007 ◽  
Vol 22 (6) ◽  
pp. 1551-1557 ◽  
Author(s):  
Shintaro Yokoyama ◽  
Hitoshi Morioka ◽  
Yong Kwan Kim ◽  
Hiroshi Nakaki ◽  
Hiroshi Funakubo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Vapor Deposition ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Relative Volume Fraction ◽  
Bottom Region ◽  
Structure And Microstructure ◽  
Metalorganic Chemical

(100)-/(001)-oriented epitaxial Pb(Zr,Ti)O3(PZT) films with various Zr/(Zr + Ti) ratios and film thicknesses were grown on (100)cSrRuO3//(100)SrTiO3substrates at 600 °C by metalorganic chemical vapor deposition. Their crystal structure and microstructure consisting of particularly mixed phases with tetragonal and rhombohedral symmetries were investigated in detail. Films with the mixed phases with tetragonal and rhombohedral symmetries were ascertained at a Zr/(Zr + Ti) ratio of around 0.50 at a thickness of more than 200 nm from x-ray diffraction (XRD) analysis, while no mixed phase region was observed for 50 nm thick film. The relative volume fraction of the tetragonal cdomain decreased with increasing film thickness for 2-μm-thick films with mixed phases, while the tetragonal adomain and rhombohedral domain increased. These mixed phases were ascertained to have originated from the same cubic PZT grown above Curie temperature from results obtained by temperature-dependent high-resolution XRD reciprocal space mapping. The transmission electron microscopy images clearly revealed that the microstructure of the film gradually changed along the film thickness, despite the fact that the film was very uniform. Tetragonal phases were dominant in the bottom region (near the interface with the substrate) of the film, while rhombohedral phase was dominant in the upper region (near the surface), which was also ascertained by cross-sectional Raman analysis. In addition, the tetragonal a/cdomain was wider in the bottom region than that in the upper region of film with mixed phases. These data clearly demonstrate that both the crystal structure and microstructure changed along the film thickness.

scholarly journals Control of Crystallinity in Nanocrystalline Silicon Prepared by High Working Pressure Plasma-Enhanced Chemical Vapor Deposition

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jung-Dae Kwon ◽  
Kee-Seok Nam ◽  
Yongsoo Jeong ◽  
Dong-Ho Kim ◽  
Sung-Gyu Park ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Crystalline Volume Fraction ◽  
Working Pressure ◽  
Scan Speed ◽  
Si Films ◽  
High Working Pressure

The crystalline volume of nanocrystalline silicon (Si) films could be successfully controlled simply by changing the substrate scan speed at the high working pressure of 300 Torr. The Si crystalline volume fraction was increased from 30% to 57% by increasing the scan speed from 8 to 30 mm/s. When the Si film was prepared at a low scan speed (8 mm/s), Si crystals of size 5 nm grew homogeneously through the whole film. The higher scan speed was found to accelerate crystallization, and crystals of size up to 25 nm were deposited in the Si film deposited when the scan speed was 30 mm/s.

The relaxation of compressive biaxial strains in SOS via microtwins

1989 ◽  
Vol 47 ◽  
pp. 608-609
Author(s):  
M. E. Twigg ◽  
E. D. Richmond ◽  
J. G. Pellegrino
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Molecular Beam Epitaxy ◽  
Compressive Stress ◽  
Vapor Deposition ◽  
Partial Dislocation ◽  
Molecular Beam ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Silicon Thin Film

For heteroepitaxial systems, such as silicon on sapphire (SOS), microtwins occur in significant numbers and are thought to contribute to strain relief in the silicon thin film. The size of this contribution can be assessed from TEM measurements, of the differential volume fraction of microtwins, dV/dν (the derivative of the microtwin volume V with respect to the film volume ν), for SOS grown by both chemical vapor deposition (CVD) and molecular beam epitaxy (MBE).In a (001) silicon thin film subjected to compressive stress along the [100] axis , this stress can be relieved by four twinning systems: a/6[211]/( lll), a/6(21l]/(l1l), a/6[21l] /( l1l), and a/6(2ll)/(1ll).3 For the a/6[211]/(1ll) system, the glide of a single a/6[2ll] twinning partial dislocation draws the two halves of the crystal, separated by the microtwin, closer together by a/3.

Nanoscale Film Thickness Gradients Printed in Open Air by Spatially Varying Chemical Vapor Deposition

2021 ◽  
pp. 2103271
Author(s):  
Abdullah H. Alshehri ◽  
Jhi Yong Loke ◽  
Viet Huong Nguyen ◽  
Alexander Jones ◽  
Hatameh Asgarimoghaddam ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Spatially Varying

CONTROLLABLE CHEMICAL VAPOR DEPOSITION SYNTHESIS OF SINGLE-WALL CARBON NANOTUBES USING MIST FLOW METHOD

NANO ◽  
2012 ◽  
Vol 07 (06) ◽  
pp. 1250045 ◽  
Author(s):  
YUN SUN ◽  
RYO KITAURA ◽  
TAKUYA NAKAYAMA ◽  
YASUMITSU MIYATA ◽  
HISANORI SHINOHARA
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Single Wall Carbon Nanotubes ◽  
Flow Method ◽  
Mist Flow ◽  
Mean Diameter ◽  
The Mean

The influences of synthesis parameters on the mean diameter and diameter distribution of as-grown single-wall carbon nanotubes (SWCNTs) with chemical vapor deposition (CVD) using the mist flow method have been investigated in detail with Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We found that CVD reaction temperature and flow rate play an essential role in controlling the mean diameter and the quality of as-grown SWCNTs. Furthermore, we found that the carbon supply kinetics can be a dominant factor to determine the diameter of as-grown SWCNTs in the present mist flow method. Under a different combination of various parameters, the mean diameter of SWCNTs can be varied from 0.9 nm to 1.5 nm controllably.

scholarly journals Thermoplasmonic of Single Au@SiO2 and SiO2@Au Core Shell Nanoparticles in Deionized Water and Poly-vinylpyrrolidoneMatrix

2019 ◽  
Vol 16 (2) ◽  
pp. 0376 ◽  
Author(s):  
Gatea Et al.
Keyword(s):  
Light Propagation ◽  
Volume Fraction ◽  
Relative Volume ◽  
Core Shell ◽  
Distribution Profile ◽  
Shell Nanoparticles ◽  
Thermal Generation ◽  
Relative Volume Fraction ◽  
Core Shell Nanoparticles ◽  
532 Nm

Metal nanoparticles can serve as an efficient nano-heat source with confinement photothermal effects. Thermo-plasmonic technology allows researchers to control the temperature at a nanoscale due to the possibility of precise light propagation. The response of opto-thermal generation of single gold-silica core-shell nanoparticle immersed in water and Poly-vinylpyrrolidone surrounding media is theoretically investigated. Two lasers (CW and fs pulses) at the plasmonic resonance (532 nm) are utilized. For this purpose, finite element method is used via COMSOL multiphysics to find a numerical computation of absorption cross section for the proposed core –shell NP in different media. Thermo-plasmonic response for both lasers is studied. The heat profile of different nanostructures is estimated. The results revealed that the temperature distribution profile was varied due to changing in the relative volume fraction between the core and the shell of nanoparticle.

Stress in Hydrogenated Microcrystalline Silicon Thin Films

1999 ◽  
Vol 557 ◽  
Author(s):  
D. Peiró ◽  
C. Voz ◽  
J. Bertomeu ◽  
J. Andreu ◽  
E. Martínez ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vapor Deposition ◽  
Volume Fraction ◽  
Chemical Vapor ◽  
Hot Wire ◽  
X Ray Diffraction ◽  
Microcrystalline Silicon ◽  
X Ray ◽  
Silicon Thin Films ◽  
Abrupt Changes

AbstractHydrogenated microcrystalline silicon films have been obtained by hot-wire chemical vapor deposition (HWCVD) in a silane and hydrogen mixture at low pressure (<5 × 10-2 mbar). The structure of the samples and the residual stress were characterised by X- ray diffraction (XRD). Raman spectroscopy was used to estimate the volume fraction of the crystalline phase, which is in the range of 86 % to 98%. The stress values range between 150 and -140 MPa. The mechanical properties were studied by nanoindentation. Unlike monocrystalline wafers, there is no evidence of abrupt changes in the force-penetration plot, which have been attributed to a pressure-induced phase transition. The hardness was 12.5 GPa for the best samples, which is close to that obtained for silicon wafers.

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