Thin films of microcrystalline and nanocrystalline -silicon carbide and silicon, where deposited on glass substrate with substrate temperature ranging from 350-400C, with deposition rate 0.5nm per pulse, by laser induced chemical vapor deposition. The deposition induced by TEACO2 laser. The reactant gases (SiH4 and C2H4) photo decompose throughout collision associated multiple photon dissociate. Such inhomogeneous film structure containing crystalline silicon, silicon carbide and amorphous silicon carbide matrix, give rise to a new type of material nanocrystalline silicon carbide in which the optical transmittance is governed by amorphous SiC phase while nanocrystalline grain are responsible for the conduction processes. This new material is promised for many new applications, lick high efficiency solar cell.
X-ray diffraction patterns and scanning microscope images revealed that nanocrystalline SiC and Si films grew at substrate temperature above 400C, while completely amorphous films grew at substrate temperature 350C.
Nd:YAG laser pulses of 9 nanosecond pulse duration and operating wavelength at 1.06 μm, were utilized to drill high thermal conductivity and high reflectivity aluminum and copper foils. The results showed a dependence of drilled holes characteristics on laser power density and the number of laser pulses used. Drilled depth of 74 ϻm was obtained in aluminum at 11.036×108 W/cm2 of laser power density. Due to its higher melting point, copper required higher laser power density and/or larger number of laser pulses to melt, and a maximum depth of 25 μm was reached at 13.46×108 W/cm2 using single laser pulse.
Require senior management of the state when developing the strategy the general budget to the clarity of the reasons that are based upon the ministries in the preparation of estimates of expenditure for the next year to justify the spending, and in the absence of targets, the ministry or government unit would not be in front, but be guided by the size of expenditure for the last year in addition to the percentage of represented an increase of appropriations required for the next year in light of the fiscal policy of the state, so the requested increase in appropriations to meet the desired increase in some of its activities and to meet the increase in salaries and prices. So must be available to the Ministry of criteria that coul
... Show MoreThe largest use of x-ray in medical by dentists, employers or persons that needed by patients with specific conditions, lead to higher exposure of x-ray that may cause many diseases. In the present work radiography films have been used in evaluating the efficiency of using unsaturated polyester polymer reinforced with lead oxide (PbO) as shield material for medical x-ray devices, many parameters studied like concentration and thickness that they are increasing the attenuation of x-ray in them. The results show that the attenuation of X-ray increasing with concentration of reinforced material and with thickness, and the optical density decreases with increasing concentration from 0% to 50%, we chose 30% as suitable concentration to increase
... Show MoreThis research deals with the effect of gallium oxide and cerium oxide as dopants on the structural and optical characteristics of tin oxide. Gallium and cerium oxide doped tin oxide was prepared with different doping concentrations (0, 0.03, 0.05 and 0.07) wt. pure and doped tin oxide thin films were prepared by the pulsed laser deposition technique. X-ray diffraction and UV-Visible spectrophotometer were employed to investigate both oxides doping effects. Results showed that all prepared samples have poly-crystalline structure with a preferred plane of crystal growth along (110), where the crystal size grew from 40.3 nm to 64.5 nm and to 43.5 nm for Ga2O3 and CeO2 doped tin oxide thin films, respectively. Transmittance dec
... Show MoreCompounds were prepared from In2O3 doped SnO2 with different doping ratio by mixing and sintering at 1000oC. Pulsed Laser Deposition PLD was used to deposit thin films of different doping ratio In2O3: SnO2 (0, 1, 3, 5, 7 and 9 % wt.) on glass and p-type wafer Si(111) substrates at ambient temperature under vacuum of 10-3 bar thickness of ~100nm. X-ray diffraction and atomic force microscopy were used to examine the structural type, grain size and morphology of the prepared thin films. The results show the structures of thin films was also polycrystalline, and the predominate peaks are identical with standard cards ITO. On the other side the prepared thin films declared a reduction of degree of crystallinity with the increase of doping ra
... Show MoreBackground: Sperm motility disorder is an important cause of infertility in male, and one of the causes of reduced motility of the sperm is the disorders of the mitochondria because it provides the required energy for sperm motility, Laser biostimulation or low-level laser therapy has a positive effect on the mitochondria and led to increasing the synthesis of ATP. Method: Twenty fresh human semen samples were used in this research study, each sample was separated into two portions, one was used as control which is not exposed to the laser beam and the other was irradiated with the wavelength of 410 nm diode laser with an output power of 100 mW and an exposure time of 60 seconds, then the measurement of
... Show MoreLead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is
... Show MoreIn this work, the structure properties of nano Lead sulfide PbS thin films are studied. Thin samples were prepared by pulse laser deposition and deposited on glass substrates at wavelength 1064nm wavelength with a various laser energies (200,300,400,500)nm. The study of atomic force microscope (AFM) and X-ray diffraction as well as the effect of changing the laser energy on the structural properties has been studied. It has been observed that the membrane formed is of the polycrystalline type and the predominant phase is the plane (111) and (200). The minimum grain size obtained was 16.5 nm at a laser energy about 200 mJ. The results showed that thin films of average granular sizes (75 nm) could be prepared.As for the optical properties,
... Show MoreHigh-intensity laser-produced plasma has been extensively investigated in many studies. In this demonstration, a new spectral range was observed in the resulted spectra from the laser-plasma interaction, which opens up new discussions for new light source generation. Moreover, the characterizations of plasma have been improved through the interaction process of laser-plasma. Three types of laser were incorporated in the measurements, continuous-wave CW He-Ne laser, CW diode green laser, pulse Nd: YAG laser. As the plasma system, DC glow discharge plasma under the vacuum chamber was considered in this research. The plasma spectral peaks were evaluated, where they refer to Nitrogen gas. The results indicated that the
... Show MoreCopper doped Zinc oxide and (n-ZnO / p-Si and n-ZnO: Cu / p-Si) thin films thru thickness (400±20) nm were deposited by thermal evaporation technique onto two substrates. The influence of different Cu percentages (1%,3% and 5%) on ZnO thin film besides hetero junction (ZnO / Si) characteristics were investigated, with X-ray diffractions examination supports ZnO films were poly crystal then hexagonal structural per crystallite size increase from (22.34 to 28.09) nm with increasing Cu ratio. The optical properties display exceptional optically absorptive for 5% Cu dopant with reduced for optically gaps since 3.1 toward 2.7 eV. Hall Effect measurements presented with all films prepared pure and doped have n-types conductive, with a ma
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