A Study the Aluminum Doped Zinc Oxide Thin Films

We investigated the optical properties of pure and Aluminum doped zinc oxide thin films as the n-type semiconductor. In this paper, we have studied the deposition of Al doped ZnO thin films on glass substrate at 350 °C, when the films were deposited with 0, 2 and 3 wt using spray pyrolysis technique. % of Al / Zn, the substrates were heated using the solar cells method. The substrate was R217102 glass in a size of 30 17.5 1 mm. All films exhibit an average optical transparency about 85 %, in the visible region. The shift of optical transmittance towards higher wavelength can be showed by the increase of band gap energy from 3.245 to 3.281 eV with increasing of Al doping from 0 to 3 wt. %. The Urbach energy Eu increase and decrease reaching to optimal value was obtained after doping at 3 wt. %

The Film Thickness Effect on The Physical Properties of NiO Thin Films Elaborated by Sol-gel Method

In this work, nickel oxide (NiO) was elaborated on glass substrate at by sol-gel technique. The NiO thin films were prepared with 0.8 M Ni(NO3)2 6H2O annealed at 600 °C for 2 h. The coating process was repeated for 13, 14, 15, 16 and 17 times to obtain a thin film, which corresponded to 124, 137, 143, 147 and 166 nm of film thickness. NiO thin films were observed as nanocrystalline with cubic structure at 166 nm with (111) and (200) peaks were observed. All NiO thin films have an average transmittance of about 80 % in the visible region. The NiO thin films have a variety in the band gap energy from 3.87 to 3.94 eV. Because of the effect of deposition times, the minimum value was found at 166 nm where this condition has the highest Urbach energy. The NiO thin films have an electrical conductivity which was increased from 7.94 x10-3 to 84x10-3 (Ω.cm)-1 when film thickness increases from 124 to 137 nm. In the end, the electrical measurements were investigated by the four-point method, with the results show good electrical conductivity at 166 nm

Study of the Optical Properties and Structure Zinc Oxide Thin Films Prepared by Spin Coating Technique

We investigated the structural and optical properties of zinc oxide (ZnO) thin film as the n-type semiconductor. In this work, the sol–gel method used to fabricate ZnO thin film on glass substrate at different solution molarities of 0.1, 0.3 and 0.5 mol/l of zinc acetate dehydrate. The DRX analyses indicated that the coated ZnO films exhibit an hexagonal structure wurtzite and (002) oriented with the maximum value of crystallite size G 69.32 nm is measured wi 0.5 mol/l. The thin film exhibit an average optical transparency is over 80 % at high molarity, in the visible region, found that the optical band gap energy was increased up to 3.25 eV at 0.5 mol/l. The minimum value of Urbach energy of ZnO thin film was achieved with 0.5 mol/l

Synthesis and Characterizations of Nanocrystalline Na and Al Codoped Nio Thin Films

In the present work, Na and Al codoped NiO thin films were successfully deposited on a glass substrate by spray pneumatic method. The effect of Al concentration on optical, structural and electrical properties was studied. The transmission spectra show that the Na and Al codoped NiO thin films have good optical transparency in the visible region. The optical band gap energy increased after co-doping by Al to maximum value was 3.926 eV for 2 % Al. The minimum value of Urbach energy was obtained at high Al concentration it is 0.319 eV for 3 % Al. The Na and Al codoped NiO films have a minimum electrical resistance obtained for 1 % Al. XRD patterns of the Na and Al codoped NiO thin films indicating that the Na and Al codoped NiO thin films have a cubic structure of NiO phase

Substrate Temperature Effect on Optical property of ZnO Thin Films

The transparent conducting ZnO thin films were deposited on glass substrate by ultrasonic spray technique. The optical, electrical and structural properties of the ZnO thin films were studied as a function of the substrate temperatures in the range of 300 to 400°C. The as deposited film exhibit an hexagonal structure wurtzite and (101) oriented. The value of grain size = 28 nm is measured of ZnO film at 350°C. All the films having high transparency in the visible region, the band gap energy decreased from 3.44 to 3.29 eV with increasing in the substrate temperatures from 300 to 400°C. The the Urbach energy decreased reaching to minimum at 350°C; indicating to decrease of the defects. The electrical resistivity of the films for 350°C is 50 Ω.cm. A systematic study on the influence of the substrate temperatures on the properties of ZnO thin films deposited by ultrasonic spray has been reported

Micro structural and Mechanics properties of Steel Nitrided by Plasma

Nitriding treatments of low alloyed steels can be performed only at relatively low temperatures in order to avoid a decrease of corrosion resistance due to nitride layers formation. These conditions promote the formation of the compound layer and diffusion zone, which shows high hardness and good corrosion resistance. In the present paper, the influence of the gas mixture N2-H2 in plasma Nitriding process on the micro structural and mechanical characteristics of 32CDV13 steel samples was evaluated. This nuance is used in manufacturing mechanical pieces that are greatly solicited in fatigue. Plasma Nitriding treatments were performed at temperatures in the range 773 K for 4 h. The modified surface layer of the Nitrided samples consists mainly of the ?’ and ? phases, according to metallographic technique analysis, it seems to be essentially a modification of the austenite matrix. High hardness values are observed in the modified layer with a steep decrease to matrix values

Collector Efficiency by Single Pass of Solar Air Heaters with and without Using Fins

This paper presents the study of heat transfer in a solar air heater by using new design of solar collector. The collector efficiency in a single pass of solar air heater without, and with using fins attached under the absorbing plate has been investigated experimentally. Due to the adding the fins inferior an absorber plate, the desirable effect of increasing the heat transfer coefficient compensates for the undesirable effect of decreasing the driving force (temperature difference) of heat transfer, while the attached fins provide an enlarged heat transfer area. In this study, the absorbing plate of solar collector is attached with fins for further improved performance. The improvements of collector efficiencies in the single pass solar air heaters with, and without fins attached; increase with increasing the mass flow rate, especially for operating at lower air flow rate. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg/s. Moreover; the maximum efficiency obtained for the 0.012 and 0.016 kg/s with, and without fins were 40.02, 51.50% and 34.92, 43.94% respectively. A comparison of the results of the mass flow rates by solar collector with, and without fins shows a substantial enhancement in the thermal efficiency

Structural Damage Detection by Using Finite Element Method as Function of Length

The work described in this paper involves the effect of length and fibre orientation of the composite damping for comparison with the analytical results. The calculation of laminate damping is performed by use of a strain energy method. The modal analysis of the structure for different loading rates is based on the analytical method used to solve the equation of free vibrations. The difference between strain energies for both cases (damaged and undamaged) are calculated by the finite element method. The structural damping of the different beams is evaluated from these energies. The decrease in frequency for different rates of loading shows the loss of stiffness for all lengths studied

Effect of the Tilt Angle of Natural Convection in A Solar Collector with Internal Longitudinal Fins,”

Abstract-We present in this paper, a series of experimental tests carried out on a solar plan, with an area of 1.8236 m 2 capture, designed in the laboratory and tested in the region of Biskra. The complete experimental setup includes the measurement of global solar radiation, wind speed, airflow velocity and temperature and the ambient air at the inlet and outlet; optimize a tilt angle. The solar collector was oriented facing south Renewable and domestic energy source, and is essential components of a sustainable energy future. This paper deals with the influence of the tilt angle of solar collectors. The optimum angle is measured by searching for the values for which the total radiation on the collector surface is a maximum for a particular day or a specific period. An application of the model is done using the experimental data measured for Biskra in Algeria. For increasing the utilization efficiency of solar collectors, it is recommended that, if it is possible, the solar collector should be mounted at the monthly average tilt angle, and the slope adjusted once a month

Study of the Optical Properties and Structure Zinc Oxide Thin Films Prepared by Spin Coating Technique

We investigated the structural and optical properties of zinc oxide (ZnO) thin film as the n-type semiconductor. In this work, the sol–gel method used to fabricate ZnO thin film on glass substrate at different solution molarities of 0.1, 0.3 and 0.5 mol/l of zinc acetate dehydrate. The DRX analyses indicated that the coated ZnO films exhibit an hexagonal structure wurtzite and (002) oriented with the maximum value of crystallite size G 69.32 nm is measured wi 0.5 mol/l. The thin film exhibit an average optical transparency is over 80 % at high molarity, in the visible region, found that the optical band gap energy was increased up to 3.25 eV at 0.5 mol/l. The minimum value of Urbach energy of ZnO thin film was achieved with 0.5 mol/l