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A layer of porous SiC was fabricated by surface anodization of commercial 4H and 6H-SiC (0001)Si face off-axis wafers. A 8.5 μm 4H–SiC epilayer was grown on porous SiC (PSC) substrates using atmospheric pressure CVD. TEM investigation on cross-sectional specimens of the CVD epitaxial layers revealed that the presence of pores in the substrate does not lead to the formation of any micropipe in the epitaxial layer. The investigation also failed to detect a more than usual dislocation density on the basal plane of the epitaxial layer. Based upon the results of various analytical techniques applied to the CVD deposit we propose that the density of screw dislocations in the epitaxial layer is less than 5–104 cm−3. It should be noted that the density of similar types of dislocations in the initial substrate as determined by the TEM was ∼106 cm−3, so this preliminary investigation indicates that the epitaxial layer grown on PSC may have a reduction in dislocation density of more than an order of magnitude over those grown on conventional SiC substrates that are not porous. Synchrotron white beam x-ray topography (SWBXT) was performed on these layers. Comparison between the dislocation density on the porous and standard epitaxial layers proved to be very similar using this technique.
We report nanometer-scale ordered arrays of cylindrical magnetic nanoparticles with low aspect ratio and ultra-high uniformity. Protracted anodization provides hexagonally ordered nanopores in amorphous Al2O3. For instance, pulsed electrochemical deposition grows Co particles of uniform length from the bottoms of these pores: these particles are polycrystalline and randomly oriented. The magnetism of the array is dominated by particle shape and by inter-particle magnetostatic interactions. A very clear transition of the anisotropy from perpendicular to in-plane is observed at a height to radius ratio of about 2. This pulse-reverse electrodeposition shows great promise for a reliable synthesis of uniform nanostructures of many metals.
Microlaminate coatings are made of many alternating layers of two hard materials that, when combined in very thin layer on the nanometer scale, produce coatings with hardness that approaches diamond. In this report, we address these properties, from our investigations on the multilayer structures of titanium carbide (TIC) and diamond-like carbon (DLC) deposited on Si (100) substrates using pulsed laser deposition (PLD) technique. X-ray diffraction and Raman spectroscopy were used for the structural studies and the mechanical properties were analysed by the nano-indention technique. Microlaminate coatings of TiC/DLC and DLC/TiC coatings with varying layers were deposited on Si(100) substrates. Analysis of mechanical properties revealed that the hardness and modulus values of the multi-layers lie between those of monolithic coatings of TIC and DLC.
A  45° twist plus 7.5° tilt grain boundary in aluminium prepared by cold rolling and annealing has been studied by high-resolution electron microscopy. The direct interpretability of the image features in terms of atomic column positions allows structural models of the grain boundary to be developed. The boundary exibits a high concentration of steps due to the 7.5° tilt from a perfect  45° quasiperiodic misorientation. Occurrence of co-incidence and pseudo co-incidence of atomic planes across the interface appears to play an important role in the formation of steps along this boundary. Local relaxation of atoms resulting from the perturbation of the  45° twist bi-crystal determines the boundary structure
In the present study, the local elastic and plastic properties of the γ- TiAl and the Laves phases have been investigated in a series of γ + Laves alloys using room-temperature compression, Vickers microhardness, and nanoindentation with an emphasis on elucidating the local property changes in γ + Laves alloys deformed at room temperature. This study shows that nanoindentation can be used to provide useful information on plastic flow in multiphase intermetallic alloys.
Strontium ruthenium oxide (SrRuO3) was deposited on Pt/(100)Si substrates at varying temperatures and 300 mTorr oxygen pressure using the pulsed laser deposition method and was found to be highly crystalline and textured when deposited over 450°C. After achieving highly crystalline SrRuO3 films, capacitors using the ferroelectric material - PZT (PbZr0.5Ti0.48O3) were successfully fabricated on Pt/(100)Si substrates. The ferroelectric properties of the films were determined by the RT66A Standardized Ferroelectric Test System. The structural properties of the films were analyzed by X-ray diffraction. Transmission electron microscopy was used to determine the crystallinity and quality of interfaces among different layers.
In this paper we discuss the growth and characterization of 3C-SiC epitaxial layers grown on both a Si substrate as well as on a novel substrate. The growth uses a typical three step process. First an etch of the Si surface is performed, second the surface of the Si is carbonized and third 3C-SiC is grown on the carbonized surface. Several characterization techniques were used to verify the quality of the 3C-SiC film. Microscopy was used to investigate the surface morphology, X-ray and electron diffraction were used to determine crystal structure, cross section TEM was used to verify crystal structure and highlight twinning, and x-ray topography was used to measure the strain fields induced in Si substrate at the 3C-SiC/Si interface.
Pb(ZrxTi1−xO3 (lead zirconate titanate or PZT) ferroelectric thin film capacitors are of considerable interest for the realization of memory devices such as nonvolatile random access memories (NVRAMs). The PZT capacitors were prepared on platinized silicon Pt/(100)Si using conducting oxide LaxSrl.xCOO (lanthanum strontium cobalt oxide or LSCO) as electrodes. The PZT and LSCO thin films were deposited by the KrF excimer laser ablation technique. The optimum preparation conditions such as oxygen pressure, laser energy influence and substrate temperature were investigated. The PZT and LSCO films grown on Pt/(100)Si are polycrystalline. The crystallographic properties of the films were determined using X-ray diffractometer (XRD) method. The cross-sectional transmission electron microscope showed very smooth interface among different layers of films. The electrical characterizations of the films including hysteresis loop, fatigue, and retention properties were determined by the RT66A Standardized Ferroelectric Test System.