PHOTOELECTRIC AND PHOTOMAGNETIC RESPONSE OF INDIUM-TIN OXIDE FILMS

Subject of Research. The goal of the present research is investigation of photoelectric and photomagnetic response of ITO (indium-tin oxide) films under UV laser irradiation. Method. The ITO films were prepared by magnetron sputtering with the thickness equal to 300nm. The films were irradiated by UV laser light with 248 nm wavelength in laser pulse energy range from 10 mJ to 150 mJ by KrF excimer laser. Metallic electrodes were deposited on the films. Information about the films surface topography was obtained by atomic force microscopy and scanning electron microscopy. The film structure was investigated by X-ray diffraction. Main Results. It was shown that voltage appears between metallic contacts under the UV light effect. The electric current was observed through resistive load. The anisotropy of electric field producing photoelectric response was demonstrated for the first time. The appearance of magnetic field under the laser light irradiation was observed for the first time. The dependence of the response voltage on the laser pulse energy was linear over the whole measured energy range. The following physical mechanism was proposed for description of the observed phenomenon: electric voltage is associated with non-uniform distribution of the average crystallite size along the film surface, and, therefore, with mean free path of the charge carriers along the film surface. Photomagnetic response could be associated with collective behavior of the large number of charged particles, created due to high intensity laser irradiation. Practical Relevance. The phenomenon being studied could be applied for creation of new optoelectronic devices, for example, modulators, optical detectors, etc. Particularly, due to linear dependence of photoelectric response on the laser pulse energy, this phenomenon is attractive for manufacturing of simple and cheap excimer laser pulse energy detectors

Numerical investigations of shape of the reflecting surface made of knitted mesh fabric being pulled on the curvilinear frame

This paper presents the surface shaping numerical investigations results of truss space constructions mesh reflectors, such as antennas and calibration and adjustment satellites. Shape-generating structure of mentioned constructions adds up to set of triangular facets, made in the form of spatio-curvilinear bar frames, bearing reflecting knitted mesh fabric pulled on it. This work proposes the algorithm of calculation of step-by-step reflecting mesh pulling on the bearing frame’s bars process, using finite elements method. Numerical execution of the developed algorithm involves for resolving the linear elasticity theory first-type boundary value problem, which implies integration of elastic body equilibrium equations without taking into account mass forces when kinematic boundary conditions are given. Analyzing when having done numerical calculations, it's possible to determine what grade obtained shapes of reflecting surfaces are precise with, and to find possible for developing variants of the antenna structure, which would allow to obtain the reflector surface shape with required accuracy by using flexible cables as a part of shape-generating structure. Comparing results of numerical investigations with experimental data received using full-scaled model of spherical calibration and adjustment satellite shows satisfactory qualitative and quantitative matching of both results

Numerical investigations of shape of the reflecting surface made of knitted mesh fabric being pulled on the curvilinear frame

This paper presents the surface shaping numerical investigations results of truss space constructions mesh reflectors, such as antennas and calibration and adjustment satellites. Shape-generating structure of mentioned constructions adds up to set of triangular facets, made in the form of spatio-curvilinear bar frames, bearing reflecting knitted mesh fabric pulled on it. This work proposes the algorithm of calculation of step-by-step reflecting mesh pulling on the bearing frame’s bars process, using finite elements method. Numerical execution of the developed algorithm involves for resolving the linear elasticity theory first-type boundary value problem, which implies integration of elastic body equilibrium equations without taking into account mass forces when kinematic boundary conditions are given. Analyzing when having done numerical calculations, it's possible to determine what grade obtained shapes of reflecting surfaces are precise with, and to find possible for developing variants of the antenna structure, which would allow to obtain the reflector surface shape with required accuracy by using flexible cables as a part of shape-generating structure. Comparing results of numerical investigations with experimental data received using full-scaled model of spherical calibration and adjustment satellite shows satisfactory qualitative and quantitative matching of both results