S H Pawar
Articles written in Pramana – Journal of Physics
Volume 12 Issue 6 June 1979 pp 593-605 Solids
The thermoluminescence of x-irradiated CaSO4: Dy phosphors has been studied for diverse activator concentrations. The concentration-dependence of these phosphors on the increase of glow peak intensities has been found to be remarkable. For higher concentration of dysprosium the concentration quenching effect has been observed. This has been attributed to the resonant transfer of energy from one activator atom to another, bringing the possible migration of energy in a solid, which is likely to get dissipated without luminescence, at the quenching site itself. The effect of irradiation time on the glow peak intensities reveals the initial linearity and a subsequent decrease indicating the possible radiation damage. The role of Na2SO4 as a charge compensator has been studied in detail. An attempt has been made to unravel the type of kinetics involved in the process, by calculating the activation energies by different methods. It has been concluded that the type of kinetics involved in the process is bimolecular.
Volume 14 Issue 2 February 1980 pp 143-147 Solid State Physics
Calcium sulphate phosphors activated with samarium as an impurity with various percentage composition have been prepared and their fluorescence rise and phosphorescence decay behaviours have been studied. The growth curve is investigated to study the density of traps. The process of filling of traps during x-ray excitation is revealed. The decay curves are analysed to study the distribution of traps, the nature of decay and kinetics involved in the luminescence process. The concentration dependence of fluorescence emission of the phosphors is also discussed.
Volume 16 Issue 2 February 1981 pp 165-171 Solid State Physics
CaSO4 phosphors activated with Sm3+ impurity in varying concentrations have been prepared and their electroluminescence systematically studied. The voltage and frequency dependence of brightness is discussed and conclusions are drawn regarding the possible mechanism involved in the process.
Volume 16 Issue 4 April 1981 pp 315-318 Chemical Physics
The dependence of photocurrent on the light intensity in CdS:Li films formed by chemical bath deposition technique is studied. The superlinearity observed is explained on the basis of increased lifetime of the photoexcited electron. The effect of oxygen adsorption in the film surface on the lifetime of the electron is studied.
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