Amorphous SIC-N Coatings: Its Properties and Applications

1994 ◽  
Vol 356 ◽  
Author(s):  
Andrew L. Yee ◽  
Hockchun Ong ◽  
Fulin Xiong ◽  
R. P. H. Chang
Keyword(s):  
Optical Properties ◽  
Film Deposition ◽  
Film Stress ◽  
Force Microscopy ◽  
Wave Measurements ◽  
Substrate Adhesion ◽  
Atomic Force ◽  
Film Substrate ◽  
Pull Testing ◽  
Amorphous Sic

AbstractLaser ablation has been used to deposit a:SiC-N films from a CVD SiC target. Depositions were carried out either in vacuum or in a nitrogen ambient ranging from 10 to 100 mT. The mechanical properties of the films versus nitrogen background pressure were assessed using nanoindentation and surface acoustic wave measurements. Deflected optical beam testing, pull testing and atomic force microscopy were used to determine film stress, film-substrate adhesion and film roughness, respectively. The optical properties were also characterized as a function of nitrogen back pressure using spectroscopic ellipsometry which determined refractive indices and predicted film compositions. Fourier transform infrared spectroscopy determined the bonding structures in the films, and finally Rutherford backscattering spectroscopy measurements were also performed. Based on the best mechanical and optical properties, the optimum film deposition conditions were obtained. It was observed that with an increase in nitrogen background pressure, oxygen content in the film, in the form of SiOx, increased significantly affecting the overall properties of the a:SiC-N films.

scholarly journals Photothermal Deflection Spectroscopy Study of Nanocrystalline Si (nc-Si) Thin Films Deposited on Porous Aluminum with PECVD

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. Ktifa ◽  
M. Ghrib ◽  
F. Saadallah ◽  
H. Ezzaouia ◽  
N. Yacoubi
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Porous Aluminum ◽  
Force Microscopy ◽  
Photothermal Deflection Spectroscopy ◽  
Atomic Force ◽  
Photothermal Deflection ◽  
Morphology Characterization

We have studied the optical properties of nanocrystalline silicon (nc-Si) film deposited by plasma enhancement chemical vapor deposition (PECVD) on porous aluminum structure using, respectively, the Photothermal Deflection Spectroscopy (PDS) and Photoluminescence (PL). The aim of this work is to investigate the influence of anodisation current on the optical properties of the porous aluminum silicon layers (PASL). The morphology characterization studied by atomic force microscopy (AFM) technique has shown that the grain size of (nc-Si) increases with the anodisation current. However, a band gap shift of the energy gap was observed.

Copper films deposited by arc ion plating at low temperatures exhibiting excellent antiwear behaviour

2011 ◽  
Vol 225 (11) ◽  
pp. 1121-1129
Author(s):  
X-M Gao ◽  
M Hu ◽  
J-Y Sun ◽  
L-J Weng ◽  
F Zhou ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Diffraction Field ◽  
Arc Ion Plating ◽  
Cu Films ◽  
Wear Rates ◽  
Force Microscopy ◽  
Ion Plating ◽  
Substrate Adhesion ◽  
Transmission Electron ◽  
Film Substrate

Cu films were prepared by arc ion plating (AIP) at low temperature ( Ts) and investigated by X-ray diffraction, field emission scanning electron microscope atomic force microscopy, transmission electron microscope, etc. It is found that low Ts (≤ 221 K) can refine the crystallite size of the Cu films and leads to compact and smooth surface structure. Further decreasing Ts to 135 K makes the inter-grain gaps turn bigger. The wear behaviours of the Cu films in vacuum were characterized using a ball-on-disk tribometer. The results show that the Cu films deposited at the Ts range of 135–221 K have better wear resistance, and the wear rates are two to three orders lower than that of the film deposited at room temperature. The compact and dense arrangement of nanoscale crystallites significantly contributes to the improved film–substrate adhesion and so the excellent antiwear behaviour.

scholarly journals Microstructure, growth mechanisms and electro-optical properties of heteroepitaxial GaN layers on sapphire (0001) substrates

1996 ◽  
Vol 1 ◽  
Author(s):  
S. Christiansen ◽  
M. Albrecht ◽  
W. Dorsch ◽  
H. P. Strunk ◽  
C. Zanotti-Fregonara ◽  
...  
Keyword(s):  
Optical Properties ◽  
Scanning Tunneling ◽  
Yellow Luminescence ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Gas Source ◽  
Atomic Force ◽  
Uv Luminescence ◽  
Image Position ◽  
Spectrally Resolved

We investigate the structure, growth morphology and the related electro-optical properties of gallium nitride (GaN) films deposited on (0001) sapphire substrates by gas source molecular beam epitaxy (GSMBE) and use transmismission electron microscopy, atomic force microscopy and scanning tunneling microscopy, photoluminescence (PL) and cathodoluminescence (CL). We find two types of specimens: one type which shows a strong UV luminescence (band-to-band transition at 358nm/3.46eV) in CL and PL and only faint yellow luminescence (Gaussian shaped CL/PL peaks at around 528nm/2.35eV), specimen ‘B’, and another type, which shows a strong UV and a comparably strong yellow luminescence, specimen ‘Y’. These two types of specimens have a rough layer surface, specimen ‘Y’ even an islanded one with, facetted hexagonal islands with a width of 1-2μm at a height of 50nm. A correlation of spectrally resolved CL images to the observed defect structure shows: (i) the yellow luminescence is homogeneously distributed over the complete specimen for ‘B’ and ‘Y’ specimens. Our investigations strongly suggest the yellow luminescence to be related to screw dislocations with , which are found randomly distributed in ‘B’ and ‘Y’ specimens with a high density of 1.3·109cm−2; (ii) the strong UV luminescence in ‘Y’ specimens is located in the troughs between adjacent surface islands, where dislocations essentially in small angle grain boundaries of edge type, i.e. with or are located; (iii) in the case of the ‘B’ specimens these dislocations are randomly distributed and so is the luminescence.

Characterization of Asymmetric Polydiacetylene Ultrathin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
D. W. Cheong ◽  
V. Shivshankar ◽  
H. C. Wang ◽  
C. M. Sung ◽  
J. Kumar ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Second Harmonic ◽  
Film Deposition ◽  
Asymmetric Structure ◽  
Blodgett Film ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Atomic Force ◽  
Ft Ir

ABSTRACTNonlinear optical (NLO) ultrathin films of a preforrned asymmetric polydiacetylene have been fabricated by Z-type Langmuir-Blodgett film deposition from the air-water interface. Induced in-plane orientation of the polydiacetylene backbone on the substrates has been confirmed by UV/Vis, FT-IR dichroism, and degenerate four wave mixing (DFWM) studies. All the measurements indicate that the backbone is prefe rentially oriented along the dipping direction. Second harmonic generation study suggests that the LB multilayers form an asymmetric structure (Z-type) due to the accumulation of 2-dimensional ordered monolayer and the dominant induced second order polarization is in the plane of the film. The film morphology and molecular orientation have been investigated by atomic force microscopy (AFM).

Comparison of the Microstructure of AlN Films Grown by MOCVD and by PLD on Sapphire Substrates

1996 ◽  
Vol 449 ◽  
Author(s):  
Yun-Xin Li ◽  
Lourdes Salamanca-Riba ◽  
V. Talyan ◽  
T. Venkatesan ◽  
C. Wongchigul ◽  
...  
Keyword(s):  
Low Density ◽  
Full Width ◽  
High Crystalline Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Film Substrate ◽  
Microscopy Images

ABSTRACT(0001) aluminium nitride thin films were grown epitaxially on (0001) Sapphire substrates by MOCVD at 1200° C and PLD at 800° C. Both films have the same epitaxial growth relationship: (0001)AlN//(0001)Sap, and the same in-plane relationship which shows a 30° rotation between A1N and Sapphire: [ 12 10]AlN//[0 110]Sap and [10 10]AlN //[ 2110]Sap. The full width at half maximum (FWHM) of x-ray rocking curve of the MOCVD A1N film was 0.16° and PLD A1N film was 0.2°. Films grown by both MOCVD and PLD showed high crystalline quality. HRTEM images showed that these films are single crystalline with very low density of defects.Dislocations in the film parallel to the film / substrate interface were observed in both A1N films. Atomic force microscopy images showed that the MOCVD films have flatter and larger terraces than the PLD films. The PLD technique for A1N growth needs to be improved further. But both films have a surface roughness of approximately 100nm.

Impact of Nitridation on Structural and Optical Properties of Epitaxial GaN Films Grown on M-Plane Sapphire by PAMBE

2015 ◽  
Vol 1736 ◽  
Author(s):  
Shruti Mukundan ◽  
Lokesh Mohan ◽  
Greeshma Chandan ◽  
Basanta Roul ◽  
S.B. Krupanidhi
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Compressive Strain ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Semipolar Gan ◽  
Nonpolar Gan ◽  
Gan Film

ABSTRACTGaN epilayers were grown on m-plane (10-10) sapphire substrates using plasma assisted molecular beam epitaxy. Impact of nitridation on structural and optical properties of GaN film was investigated. The film grown on a nitridated surface resulted in a nonpolar (10-10) orientation while without nitridation caused a semipolar (11-22) orientation. The high resolution X-ray diffraction studies confirmed the orientation of the GaN films. X-ray rocking curve showed better crystallinity of semipolar as compared to nonpolar GaN. Atomic force microscopy showed smoother films in case of nonpolar GaN which might be in account of the nitridation treatment. Room temperature photoluminescence study showed nonpolar GaN to have higher value of compressive strain as compared to semipolar GaN film, which was further confirmed by room temperature Raman spectroscopy. Despite the fact that it is difficult to obtain high-quality nonpolar material due to the planar anisotropic nature of the growth mode, we hereby report the development of non-polar GaN of usable quality, on an m-plane sapphire, involving controlled steps of nitridation.

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