Identification of stacking faults in silicon carbide by polarization-resolved second harmonic generation microscopy.

Although silicon carbide is a highly promising crystalline material for a wide range of electronic devices, extended and point defects which perturb the lattice periodicity hold deep implications with respect to device reliability. There is thus a great need for developing new methods that can detect silicon carbide defects which are detrimental to device functionality. Our experiment demonstrates that polarization-resolved second harmonic generation microscopy can extend the efficiency of the "optical signature" concept as an all-optical rapid and non-destructive set of investigation methods for the differentiation between hexagonal and cubic stacking faults in silicon carbide.

On the structured imperfections of bulk GaSb using high resolution transmission electron microscopy.

GaSb is a promising III-V direct band gap semiconductor with sphalerite type FCC structure. Its band gap value has made it an excellent candidate for the conversion of infrared radiation to electricity. The wafers of GaSb, that were studied, originated from ingots grown with the Liquid Encapsulated Chochralski method.

Transmission electron microscopy analysis of phase separation in GaInAsSb films grown on GaSb substrate.

The GaSb-based quaternary alloys are a good choice for thermophotovoltaic applications. The thermophotovoltaic cell converts infrared radiation to electricity, using the same principles as photovoltaic devices. The aim of the present work was the microstructural study of such an alloy, namely Ga(0.

Effect of heat sterilization on surface characteristics and microstructure of Mani NRT rotary nickel-titanium instruments.

Aim: To evaluate the effect of repeated dry heat sterilization on surface characteristics and microstructure of Mani nickel-titanium rotary instruments.

Methodology: Thirty-three new Mani NRT instruments, size 30, taper 0.04 and 25 mm in length were examined.

SEM observations and differential scanning calorimetric studies of new and sterilized nickel-titanium rotary endodontic instruments.

Scanning electron microscopy (SEM) and differential scanning calorimetric (DSC) studies were utilized to investigate surface and microstructure of two brands of rotary nickel-titanium (NiTi) endodontic instruments, in the as-received condition and after subjection to 1, 6, and 11 sterilization cycles. A total of 66 ProFile (n = 33) and Flexmaster (n = 33) files were examined. SEM observations indicated the presence of surface imperfections and adherent material in all new and sterilized instruments and an increase in surface roughness of the instruments that underwent multiple sterilizations.

Nanostructuring, compositional fluctuations, and atomic ordering in the thermoelectric materials AgPb(m)SbTe(2+m). The myth of solid solutions.

The nature of the thermoelectric materials Ag(1-x)Pb(m)SbTe(m+2) or LAST-m materials (LAST for Lead Antimony Silver Tellurium) with different m values at the atomic as well as nanoscale was studied with powder/single-crystal X-ray diffraction, electron diffraction, and high-resolution transmission electron microscopy. Powder diffraction patterns of different members (m = 0, 6, 12, 18, infinity) are consistent with pure phases crystallizing in the NaCl-structure-type (Fmm) and the proposition that the LAST family behaved as solid solutions between the PbTe and AgSbTe2 compounds. However, electron diffraction and high resolution transmission electron microscopy studies suggest the LAST phases are inhomogeneous at the nanoscale with at least two coexisting sets of well-defined phases.

Cubic AgPb(m)SbTe(2+m): bulk thermoelectric materials with high figure of merit.

The conversion of heat to electricity by thermoelectric devices may play a key role in the future for energy production and utilization. However, in order to meet that role, more efficient thermoelectric materials are needed that are suitable for high-temperature applications. We show that the material system AgPb(m)SbTe(2+m) may be suitable for this purpose.

Surface investigations on HgBr2 single crystals by using confocal scanning laser microscopy.

A confocal scanning laser microscope operating at 514 and 488 nm has been used to obtain two-dimensional (2-D) images of the mercuric bromide (HgBr2) crystal surface by photoluminescence, reflection, and transmission phenomena. Our measurements indicate that regions showing a strong photoluminescence may appear on the surface. By processing the 2-D images.