نتایج جستجو برای: band gap shift

تعداد نتایج: 391917  

2013
Anindya Roy Chris G. Van de Walle

Using first-principles calculations, we study the effect of transition-metal additives (Ti, Fe, Co, and Ni) on the rate of hydrogen desorption in MgH2. The presence of large concentrations of transition-metal impurities causes the Fermi level to shift according to the position of the transition-metal acceptor/donor levels in the band gap. This shift can lower the formation energy of native defe...

Journal: :Nano letters 2007
Prasanth Gopinath Aditya Mohite Hemant Shah Ji-Tzuoh Lin Bruce W Alphenaar

The effect of uniaxial strain on the photocurrent spectrum of semiconducting single-wall carbon nanotubes is measured. The energy of the lowest-lying free electron transition is observed to shift with strain as predicted by a simple noninteracting model. The higher-order transitions also shift with strain, but being excitonic, their strain dependence differs from the predictions for the free ca...

2008
F. Dagdelen S. Acar S. B. Lisesivdin M. Kasap Y. Aydogdu M. Bosi

We presented the results of electrical and optical studies of the properties of InxGa1−xN epitaxial layers (0.060 ≤ x ≤ 0.105) grown by metalorganic vapour phase epitaxy. Resistivity and Hall effect measurements of the samples were carried out at room temperature. Optical properties of the samples were characterized by photoluminescence and optical absorption spectroscopy. The comparison betwee...

2004
P. Thiyagarajan M. Kottaisamy K. Sethupathi M. S. R. Rao

We prepared a new Mn activated ZnS phosphor co-doped with Ba that showed an interesting shift in the spectral emission from amber-yellow to red colour. We believe it to be an important result to understand the underlying Physics and for display devices. To realize this, attempts were made to fine tune the band gap of ZnS with various concentrations of Ba co-doping within the concentration range...

In this study, Nitrogen doped TiO2 photocatalysts were prepared by the sol gel method and physicochemical properties were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM), photoluminescence, and energy dispersive X-ray spectroscopy (DRS) techniques. The XRD data indicated that the nanoparticles had the same crystals structures as the pure TiO2</su...

Zinc sulfide (ZnS) films were deposited through a simple and low cost spray pyrolytic technique using mixed aqueous solutions of zinc nitrate and thiourea. The structural and optical properties of these films were investigated as a function of initial (Zn:S) molar ratio in the precursor solution, which varied between (1:1) and (1:3). X-ray diffraction (XRD) analysis revealed that wurtzite...

Journal: :Physical review 2022

The Chandrasekhar-Clogston limit normally places stringent conditions on the magnitude of magnetic field that can coexist with spin-singlet superconductivity, restricting critical induced Zeeman shift to a fraction superconducting gap. Here, we consider model system where Cooper pairing in dispersive band crossing Fermi level is boosted by an additional flat-band located away from level. boosti...

2009
Sylvie Rangan Eric Bersch Robert Allen Bartynski Eric Garfunkel Elio Vescovo

Valence-band and conduction-band edges of ultrathin oxides SiO2, HfO2, Hf0.7Si0.3O2, and Al2O3 grown on silicon and their shifts upon sequential metallization with ruthenium have been measured using synchrotronradiation-excited x-ray, ultraviolet, and inverse photoemissions. From these techniques, the offsets between the valence-band and conduction-band edges of the oxides, and the ruthenium me...

2004
L. K. Pan Y. K. Ee C. Q. Sun G. Q. Yu B. K. Tay

The effect of plasma fluorination on the band gap, 2p core-level energy, and the dielectric behavior of porous silicon ~PS! prepared under constant conditions has been examined using Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, photoluminescence, and reflection. It has been found that with increasing extent of fluorination, the band gap expands, and the 2p level an...

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