نتایج جستجو برای: band gap shift
تعداد نتایج: 391917 فیلتر نتایج به سال:
In this letter, titania nanopowder and titania-silica nanocomposite were prepared using sol-gel method. Although the size of nanocrystallites and the mass fraction percent age of rutile phase ( after phase transformation ) were increased by increasing calcination in the two samples , their size in titania-silica nanocomposite was smaller than that in pure titania . Moreover, the calculations ...
The Photoexcited carrier lifetime (τ) and peak to valley transmission difference (ΔTp-v) in direct and indirect band gap crystals has been investigated by the use of single beam open and closed aperture z-scan technique using frequency doubled Nd:YAG laser. The peak to valley transmission difference (ΔTp-v) is found to be of the order of 10-2 in case of direct band gap crystals and of the order...
cadmium sulphide (cds) nanoparticles were prepared using microemulsion method using cadmium chloride as cadmium source and sodium sulphide as sulphur source. the obtained nanoparticles structures were characterized by x-ray diffraction (xrd) and transmission electron microscopy (tem) whereas optical characterization was done by ultra violet-visible absorption. xrd result shows that cds nanopart...
در این تحقیق اتصال پپتیدی نانولوله به صفحات گرافن مورد بررسی قرار گرفته است. از میان جنبه های مختلف قابل بررسی برای این ساختارها، مطالعات ساختاری، مطالعات مربوط به انرژی تشکیل پیوند، مطالعاتnmr) )neuclear magnetic resonance و nuclear quadrupole resonance (nqr)و molecular electrostatic potential (mep)، مطالعات مربوط به شکاف انرژی (band gap)هریک از این هیبریدهای نانولوله - گرافن و همچنین بررسی ان...
boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...
in this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for te/tm modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. after that, effects of parameters like...
Study of the band – gap shift in CdS films : Influence of thermal annealing in different atmospheres
Study of the band–gap shift in CdS films: Influence of thermal annealing in different atmospheres. Abstract We study by photoacoustic spectroscopy the band–gap shift effect of CdS films. The CdS films were grown by chemical bath deposi-tion and exposed to different annealing atmospheres over a range of temperature in which the sample structure is observed to change. We show the band–gap evoluti...
We present the results of optical studies of the properties of InxGa12xN epitaxial layers (0,x ,0.2) grown by metalorganic chemical vapor deposition. The effects of alloying on the fundamental band gap of InxGa12xN were investigated using a variety of spectroscopic techniques. The fundamental band-gap energies of the InxGa12xN alloys were determined using photomodulation spectroscopy measuremen...
Intense-Laser Solid State Physics: Unraveling the Difference between Semiconductors and Dielectrics.
Experiments on intense laser driven dielectrics have revealed population transfer to the conduction band to be oscillatory in time. This is in stark contrast to ionization in semiconductors and is currently unexplained. Current ionization theories neglect coupling between the valence and conduction band and therewith, the dynamic Stark shift. Our single-particle analysis identifies this as a po...
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