We demonstrate theoretically that it is possible to realize terahertz (THz) fundamental band-gap between the electron mini-band in the InAs layer and the heavy-hole mini-band in the GaSb layer in InAs/GaSb based type II superlattices (SLs). The THz band-gap can be tuned by varying the sample growth parameters such as the well widths of the InAs and/or GaSb layers. The presence of such band-gap ...

The samples of CR-39 polymer (TASTRAK, Bristol, England) were annealled thermally at various temperatures ranging from 100oC to 180oC for 1 hour, in air. FTIR spectroscopy reveals the structural degradation of CR-39 polymer due to thermal annealing above its glass transition temperature. Optical band gap of pristine and thermally annealed samples has been determined using UV-Visible absorption ...

ZnO thin films with preferred orientation along the (002) plane were prepared onto the glass substrates by the sol-gel spin coating method for different post- annealing temperatures. The XRD study confirms that the thin films grown by this method have good crystalline hexagonal wurtzite structure. The optical band gap of the samples was determined from UV-visible spectra. It is found that the s...

in this study we investigate the effect of atoms such as b, n, ge and sn on the optical and the electrical properties of capped (5, 0) zigzag carbon nanotube, using dft calculation method. these elements were attached to the one end of the carbon nanotube. we considered four different structure designs as possible candidates for a p-n junction device. the electrical properties of these structur...

We report on a temperature-dependent band gap property of epitaxial MoSe2 ultrathin films. We prepare uniform MoSe2 films epitaxially grown on graphenized SiC substrates with controlled thicknesses by molecular beam epitaxy. Spectroscopic ellipsometry measurements upon heating sample in ultra-high vacuum showed temperature-dependent optical spectra between room temperature to 850 °C. We observe...

The design of one-dimensional photonic crystals and the analysis of their optical properties have been performed using band diagram and forbidden gap map methods. It has been shown that the latter method is more useful for practical applications since i it can be applied for any number of periods and ii it is more suitable for the selection of a filling fraction in a wide range of values using ...

Organometal halide perovskites are promising materials for optoelectronic devices. Further development of these devices requires a deep understanding of their fundamental structure-property relationships. The effect of pressure on the structural evolution and band gap shifts of methylammonium lead chloride (MAPbCl3) was investigated systematically. Synchrotron X-ray diffraction and Raman experi...

It has been predicted that application of a strong electric field perpendicular to the plane of bilayer graphene can induce a significant band gap. We have measured the optical conductivity of bilayer graphene with an efficient electrolyte top gate for a photon energy range of 0.2-0.7 eV. We see the emergence of new transitions as a band gap opens. A band gap approaching 200 meV is observed whe...

The research in new organic π-conjugated molecules with specific properties has become one of the most interesting topics in fields of materials chemistry. These materials are promising for optoelectronic device technology such as solar cells. On the other hand, the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The Co...