Sharif Digital Repository

We propose a recipe to construct the discrete light-cone quantization (DLCQ) Hamiltonian of type IIB string theory on the anti-de Sitter (AdS) (and/or plane-wave) background. We consider a system of J number of coincident unstable non-Bogomol'nyi-Prasad-Sommerfield (BPS) D0 branes of IIB theory in the light-cone gauge and on the plane-wave background with a compact null direction, the dynamics of which is described by the worldline U(J) gauge theory. This configuration suffers from tachyonic instabilities. Having instabilities be cured through the process of open string tachyon condensation, by expanding the theory about true minima of the effective potential and furthermore taking the low... 

Today manufacturing of high efficiency chalcogenide thin film solar cells is based on high cost vacuum-based deposition processes at high temperature (>500 °C) and in chalcogen -containing atmosphere. In this paper, we introduce a simple vacuum-free and selenization-free, solution processing for fabricating a superstrate-type CuInS2 (CIS) solar cell. The absorber, buffer and blocking layers were all deposited by spin coating of molecular precursor inks. We demonstrate the deposition of In2S3 buffer layer by sol-gel spin casting for the first time. The rapid sintering process of CIS layer was carried out at 250 °C that is considered a very low temperature in CIGS thin-film technologies. A... 

The fabrication of high performance, solution-processed CIGS family solar cells is based on high-temperature crystallization processes in chalcogen-containing atmosphere and/or using dangerous solvents like hydrazine. The non-hydrazine sulfurization- and selenization-free reports typically suffer from poor grain structures. We report a facile strategy to overcome grain growth limitations at very low temperature processing (250 °C). Selenium free Superstrate configuration CuInS2 (CIS) solar cells are fabricated using a nanocrystals ink which avoiding from high temperature selenization or/and sulfurization is targeted. We investigated the effect of intentional M doping (M = Sb, Zn, Cd and Sn)... 

This paper proposes, for the first time, a tunable left handed transmission line consisting of a strip line sandwiched between a ferrite superstrate and a dielectric substrate containing a metallic wire array. The left-handed behavior is realized by combining the negative permittivity of the wire array with the negative permeability of the longitudinally magnetized ferrite substrate despite them being spatially separated. Theoretical and numerical results demonstrate the tunability of the left-handed frequency band by changing the DC bias magnetic field applied to the ferrite. Compared to other tunable lefthanded structures, the fabrication requirements on this structure are not critical,... 

Planar superstrate CuInS2 (CIS) solar cell devices are fabricated using totally solution-processed deposition methods. These Cd-free devices are structured by FTO/TiO2/In2S3/CIS/carbon, where TiO2 and In2S3 are deposited by spray pyrolysis, and a CIS film is deposited using spin-coating followed by annealing at 250 °C. The pasted carbon layer is utilized as the anode. No further sulfurization or selenization is employed. The Cu/In ratio in the ink is found as a critical factor affecting the morphology and crystallinity of the film as well as the photovoltaic performance of the device. An optimum Cu/In = 1.05 results in large-grain films with sharp diffraction peaks and, subsequently, optimal...