62 research outputs found

    The Effect of the Growth Condition on the Properties of the New Material Sn3Sb2S6 Thin Films

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    Sulfosalt Sn3Sb2S6 material was synthesised by the horizontal Bridgman method. X-rays diffraction analysis of the powder showed that only homogenous Sn3Sb2S6 phase is present in the ingot. Sn3Sb2S6 thin films were deposited by a single source vacuum thermal evaporation with different thicknesses on glass substrates. The optical and structural properties of the films were studied as a function of thicknesses and temperature substrates. It is interest to note that Sn3Sb2S6 films exhibit polycrystalline structures along (416) preferred plane without heating the substrates. In addition, we note that as the thickness increases from 150 nm to 430 nm the average grain size increases from 190 to 350 °A. The samples have direct bandgap energies of 1.5 - 1.75 eV. Furthermore, we found that the absorption coefficient in all cases reached 104 cm−1. So, Sulfosalt Sn3Sb2S6 thin films could be used as a potential candidate in may technological applications such as photovoltaic solar cell

    Approach for Integrating Indirect Evaporative Cooling System into Contemporary Architecture

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    Nowadays, the knowledge of building ecology focuses on energy efficiency and how to integrate environmental and climatic parameters into HVAC and thus enhances space qualities such as comfort ability. The aim of this paper is to demonstrate the rule of Indirect Evaporative Cooling systems in sustainability of contemporary architecture in hotarid and hot-humid climate. An approach for integrating a novel Sub-Wet Bulb Temperature Evaporative cooler into contemporary architecture is presented. The system uses porous clay materials, as wet media, embedded with heat pipes heat exchangers, the supply air and working air flows were staged in separate ducts and in counter flow direction. Modelling and experimental results show that supply air would be cooled to below wet bulb temperature achieving a considerable cooling capacity and effectiveness. This performance would make the system a potential alternative to conventional mechanical air conditioning systems in buildings.Qatar National Research , NPRP grant No. 4 -407 -2 -15

    Investigation of CuIn1-xGaxSe2 thin films co-evaporated from two metal sources for photovoltaic solar cells

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     CuIn1-xGaxSe2 (CIGS) thin films were grown by co-evaporation using two sources for the metal elements (Cu, Ga and In). A Mo coated soda lime glass substrates heated at 500 °C was used for the deposition. X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirm that these films are polycrystalline with a chalcopyrite structure and showed homogeneous grain size estimate about 25 nm. X-ray photoelectron spectroscopy (XPS) was performed to analyse the binding energy values of Ga3d and O1s onto CIGSe layers. The conductivity measurements in the temperature range of 40-400 K were carried out for 0.05≤ x ≤ 0.23. The effect of grain boundary scattering on the electrical transport played an important role in describing the transport processes in these films. The bowing factor is discussed taking into account the deposition techniques of CIGS films. It has been noticed that the open circuit voltage (Voc) is influenced by Ga content and the energy gap value of the absorber CIGS thin layers and yielded a poor efficiency of solar cells

    Study of Structural, Morphological and Optical Properties of Sb2S3 Thin Films Deposited by Oblique Angle Deposition

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    Sb2S3 thin films were deposited by thermal evaporation method with oblique angle deposition technique. During the deposition, the substrate temperature was maintained at Ts = 180 â—¦C and the deposition angle was fixed at a = 0â—¦, 20â—¦, 40â—¦, 60â—¦, 70â—¦ and 85â—¦. X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and UV- Vis- NIR spectra were used to characterize the structural, surface morphology and optical properties respectively of the layers. X-ray diffraction spectra indicated that all the deposited Sb2S3 films are amorphous. The band gaps of the thin films were found to be direct allowed transitions and are around 1.87 eV. In addition it was found that the refractive index decreases from 2.98 for a = 0â—¦ to 2.28 for a = 85â—¦. The relationship between the flux incident angle a and the column angle b was also explored

    Reinforcement Q-Learning and Neural Networks To Acquire Negotiation Behaviors

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    Thermally induced changes in optical and electrical properties of SnSb

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    Sulfosalt SnSb2S4 films for optical and electrical applications have been prepared on glass substrates by thermal evaporation and subsequently thermally annealed in vacuum at temperatures from 100 to 200 °C. The optical and structural properties of the films were studied as a function of the annealing temperature. The SnSb2S4 films exhibit a polycrystalline structure and undergo abrupt changes in electrical and optical properties at a transition temperature of 140 °C. After annealing below the transition temperature, the films are highly resistive with a dominant amorphous component, but when annealed above this temperature, the samples exhibit p+-type semiconductor behaviour with a dominant crystalline componen

    Interferential polychromatic filters

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    The reflection properties of one-dimensional generalized Cantor-like multilayer (GCLM) are investigated numerically in the visible range. Strong correlation between the stack geometry and the properties of the optical reflection spectra is found, namely spectral scalability and sequential splitting. The construction of multilayer systems according to the definite Cantor distribution brings improvements to the reflection properties. In particular, the widening of the band gap and the thin peak appearance in the reflection spectra whose number increases with the division number in the (GCLM). Optical properties of (GCLM) inserted between two periodic stacks are numerically investigated. We chose SiO2(L) and TiO2 (H) as two elementary layers. The study configuration is H(LH)5[GCLM]PH(LH)5 which forms an effective interferential filter in the visible spectral range. We show that the number of resonator peaks is dependent on the repetition of the number P of the (GCLM). The best performances are obtained in particular for the symmetrical configurations of the (GCLM) and especially for P an odd number

    Interferential polychromatic filters

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