A pulsed metalorganic chemical vapor deposition (MOCVD) technique, specifically designed for high quality AlN/GaN superlattices (SLs) is introduced. Optical quality and precise controllability over layer thicknesses are investigated. Indium is shown to improve interface and surface quality. An AlN/GaN SL designed for intersubband transition at a telecommunication wavelength of ~1.5 μm, is grown...

We report here a simple wet chemical process to synthesize ZnO nanoparticles. The morphology of the nanoparticles was observed in field emission scanning electron microscope. The nanoparticles have average diameter ~ 100 nm. The optical property of the synthesized ZnO nanoparticles was investigated using UVvisible absorption spectra. The synthesized nanoparticles exhibit strong absorption at ~ ...

Title of Document: A STUDY OF OPTICAL, PHYSICAL AND CHEMICAL PROPERTIES OF AEROSOLS USING IN SITU MEASUREMENTS Zahra Chaudhry, Ph.D., 2009 Directed By: Professor Zhanqing Li, Department of Atmospheric and Oceanic Science Using a simple sampling apparatus, aerosol particles were collected on a polycarbonate substrate in various locations around the world. The focus of this study was Xianghe, Chi...

Tunable far-infrared-vacuum-ultraviolet two color ionization is used to obtain vibrational spectra of neutral silicon clusters in the gas phase. Upon excitation with tunable infrared light prior to irradiation with UV photons we observe strong enhancements in the mass spectrometric signal of specific cluster sizes. This allowed the recording of the infrared absorption spectra of Si(6), Si(7), a...

2-Mercapto-3-phenyl-4-quinazolinone complexes of copper is synthesized characterized on the basis of chemical properties, elemental data, magnetic susceptibility and characteristic absorption band in IR and ultra-violet absorption frequencies. The structure of complex underline the ability of Cu (I) centre to exist in distorted tetrahedral environment. The binding mode of the ligand is usual an...

For the first time, patterned growth of boron nitride nanotubes is achieved by catalytic chemical vapor deposition (CCVD) at 1200 C using MgO, Ni, or Fe as the catalysts, and an Al2O3 diffusion barrier as underlayer. The as-grown BNNTs are clean, vertically aligned, and have high crystallinity. Near band-edge absorption ∼6.0 eV is detected, without significant sub-band absorption centers. Elect...

In this paper, the infra-red absorption spectra of a number of crystalline natural estrogens are presented and considered in relation to chemical structure. As a group, the natural estrogens are distinguished chemically from other steroids by the benzenoid structure of Ring A, which gives rise to certain infra-red absorption bands by which their spectra may be differentiated from those of other...

High-level ab initio molecular orbital calculations were performed to predict chemical reaction pathways and UV absorption maxima. It is indicated that the search for transition states in the reaction of disilenes with water by ab initio MO calculations in combination with the frontier MO theory provides a good perspective of the reaction mechanisms. UV absorption maxima of diaminosilylene dime...

The ability of Congo red to form complexes with α-proteins, human growth hormone and human interferon-α2b, was found by absorption difference spectroscopy. A human growth hormone– Congo red complex was isolated by gel-permeation chromatography, and its visible absorption spectrum was registered in comparison to free dye. The ability of Congo red to induce dimerization of human growth hormone wa...