Polymeric thin films of Polystyrene (PS) doped with DCM laser dye have been prepared using casting method and pure thin films of PS. Optical properties for deposed thin films on glass substrate with 0.237μm was prepared using casting method involved absorptions spectra measurement using UV mate SP-8001 double-beam spectrophotometer covering the wavelengths range 190-1100nm, where the absorption coefficient was calculated and the direct energy gap was 3.9eV for PS thin film, energy gap for PS-DCM thin film was 2.2eV. While for indirect transitions the energy gap for PS thin film was 2.25eV and phonon energy was 0.55eV, but the energy gap for PS-DCM film was 1.4eV and phonon energy was 0.5eV.
In this paper, the design of spray pyrolysis system to prepare thin films of various materials system. The study showed that films prepared with good characteristics. films were prepared from lead oxide PbO this way. The study of the optical properties of these films and through recording the absorbance spectrum and transmittance spectrum of films prepared in the wavelength range (300-1100) nm . Optical constant for thin films prepared such as absorption coefficient, the extinction coefficient , the refractive index and the optical energy gap was calculated as well. films prepared found that it has a direct energy gap value 3.1eV.
Cubic AgSbS2nanostructured flowers of nanorods were successfully synthesized by microwave-assisted refluxing of AgNO3, Sb(CH3COO)3, and L-cysteine (C3H7NO2S) dissolved in ethylene glycol at the pH of 4, characterized by X-ray diffraction (XRD) and electron microscopy (EM). The 1.89 eV direct energy gap was determined by UV-visible absorption, including two 688 and 857 nm emission wavelengths by photoluminescence (PL) spectroscopy. A possible formation mechanism of AgSbS2nanostructured flowers was also proposed according to the experimental results.
Purified cadmium sulfide crystals were successfully synthesized from 1:2 molar ratio of Cd and S powders by a 900 W microwave plasma for 120 min and 140 min. In the present research, XRD and SAED patterns including SEM, TEM, and FIB images were used to indicate phase and morphology of the products, with their Raman peaks at 303 and 605 cm-1. Photoemission was determined to be 537 nm, and direct energy gap (Eg) to be 2.48-2.51 eV.
Transparent and conducting SnO 2 thin film has been produced on quartz substrate using rapid thermal oxidation of pure Sn in air at different oxidation temperature and oxidation time. The transmittance T in the visible and NIR was investigated, the allowed direct energy gap was determined to be 3.18 eV at optimum condition of 600° and 90 s. The dependence of the resistivity on the film thickness and oxidation time has been studied. The optimum thickness of high transmittance and lowest resistivity is about 150 nm for SnO 2 were ρ = 2 × 10-2Ω cm and T = 88%.
Photoluminescence Spectra From The Direct Energy Gap of a-SiQDs