The quasiparticle band gaps of semiconducting carbon nanotubes (CNTs) supported on a weakly-interacting hexagonal boron nitride (h-BN) substrate are computed using density functional theory and the GW Approximation. We find that the direct band gaps of the (7,0), (8,0) and (10,0) carbon nanotubes are renormalized to smaller values in the presence of the dielectric h-BN substrate. The decrease i...

cd1-xmnxs (x = 0, 0.1, 0.2) nanoparticles, prepared by co-precipitation method under ultrasonic irradiation, were studied by means of x-ray diffraction, scanning electron microscopy, ftir and uv-vis  spectroscopy measurements. the average particle size of nanoparticles from the scanning electron microscopy image is about 20-30 nm. results show that partial substitution of cd by mn leads to a re...

the purpose of this paper is the generalization of structure factor for rods by polygon section in two dimensional phononic crystals. if we use the plane wave expansion method (pwe) for the propagation of acoustic waves in 2d phononic crystals, structure factor will be an important quantity. in order to confirm the obtained relations, we have calculated the band structure for xy and z vibration...

zno nanorod was prepared by microwave assisted method. the crystal structure of the nano powders were confirmed by x-ray diffraction analysis and the mean particle size was estimated by the scherrer,s formula .the surface morphology of the nano particles were analyzed by   using sem . the absorption spectrum of the material in the uv-vis range was recorded .the energy band gap of the material w...

An electron-hole plasma recombination model is used to fit the room-temperature electroluminescence from metal–oxide–silicon tunneling diodes. The relatively narrow line shape in the emission spectra can be understood by the quasi-Fermi level positions of electrons and holes, which both lie in the band gap. This model also gives a narrower band gap than that of bulk silicon. The surface band be...

The most significant process for optical coating is variant of vacuum deposition. Zinc sulphide having direct and large band gap which is use in opto electronics. By using ZnS material in thermal evaporation technique and characterizing the minimum reflectance and maximum transmittance in visible wavelength and energy gap increases with increasing thickness having direct and large band gap. Whe...

ZnS12xTex (0.022) isoelectronic centers. The pressure coefficients of the emission bands ar...

highly crystalline and pure lithium metasilicate (li2sio3) and lithium disilicate (li2si2o5) nanomaterials were synthesized by hydrothermal method and characterized by pxrd technique. the changes in the morphology and particle size of the synthesized nanomaterials with reaction time were investigated using sem technique. the uv-vis and photoluminescence spectra of the compounds were studied. th...

Photovoltaic cells are able to convert sunlight into electricity, providing enough of the most abundant and cleanest energy to cover our energy needs. However, the efficiency of current photovoltaics is significantly impeded by the transmission loss of sub-band-gap photons. Photon upconversion is a promising route to circumvent this problem by converting these transmitted sub-band-gap photons i...

The stable configurations, electronic structure and magnetic properties of B16N16, B8C24, Al and P inserted (BC3)8 was studied by performing density functional theory (DFT) calculations of the NMR parameters. The results indicate that B8C24 has semiconductivity property and be effectively modified by inserti...