Browsing by Author "Jain, G. C."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    A distributed parameters model for the solar cell
    (1966) Stuber, Fred Martin; Jain, G. C.
    In order to find a method for calculating the optimal gridding of p-n junction solar cells, a distributive-circuitelement model has been derived. It consists of a chain of T elements. They have a resistance in the series path. The shunt paths consist of the diode together with the series resistance, the shunt resistance and the current source. The parameters in the model can be derived from the measurements of the cell under reverse biased, forward biased and illuminated conditions. The model has been employed to derive the optimum stripe separation. This conforms with the prevalent design practice.
  • Thumbnail Image
    Item
    Doping of ferroelectric solid solution of (Ba, Sr) TiO_ to increase the RC time constant
    (1965) Ravindran, Kuruppath; Jain, G. C.
    Solid solutions of various percentages of SrTiO3 in BaTiO3 were prepared and their dielectric properties and electrical resistivities were studied. It is observed that SrTiO3 increases the Curie constant of BaTiO3. Whereas the Curie temperature of the solid solutions linearly decreases with increasing amount of SrTiO3, an oscillatory behavior was observed for both the reciprocal of the permittivity at Curie temperature and the Curie constant, with the maxima of both occurring at the same concentration. A solid solution of (Ba0.77, Sro23) TiO3 was doped with In203. It was observed that In203 increased the resistivity of the material, there being an optimum doping level for the highest resistivity. This is attributed to P-type behavior of indium in the BaTiO3 lattice. At low doping levels In203 does not affect the Curie temperature, permittivity at Curie temperature or the Curie constant of the material. It is proposed that BaTiO3 can be treated analogously to the semiconductor elements of the IVth group like silicon or germanium in so far as its impurity doping behavior is concerned. The advantages of a capacitor made of In203 doped (Ba0.77, Sr0.23) TiO3 solid solution in the conversion of solar energy to electrical energy on spinning satellites are discussed.
  • Thumbnail Image
    Item
    Effect of dimensions on the efficiency of radiant energy cells
    (1966) Li, Sheng-San; Jain, G. C.
    This work deals with the enhancement of the quantum efficiency and photovoltaic energy conversion efficiency of a P-N semiconducting cell by optimizing the dimensions of the cell. Based on the Shockley-Read statistics a general expression for the quantum efficiency of monochromatic incident radiant energy photons has been derived in terms of the absorption coefficient of the incident photons, the minority carrier diffusion length, the built-in electrostatic field appearing in diffused cells and the surface recombination velocity in the exposed layer of the cell. Although the expressions derived may be used for all semiconducting P-N cells, special efforts have been made in the analysis and the computations of the Germanium P-N cell. The Germanium cells show a great potential for photovoltaic energy conversion from radiant energy sources other than the sun. The results for Germanium indicate that the quantum efficiency strongly depends upon the thicknesses of the exposed and base layers. The built-in electrostatic field and the surface recombination velocity in the exposed layer influence the quantum efficiency greatly. Optimization studies for the thicknesses of the exposed ane base layers of a N-P type Germanium for different values of minority carrier diffusion length, built-in electrostatic field and surface recombination velocity have been worked out.
  • Thumbnail Image
    Item
    Temperature dependence of thermoelectric figure of merit and maximum thermal efficiency of a thermoelectric generator
    (1966) Tserng, Hua Quen; Jain, G. C.
    The expression for the dimensionless figure of merit of a semiconductor of given carrier mobility and lattice thermal conductivity expressed in terms of reduced temperature has been numerically evaluated for various scattering indices. The results are presented graphically enabling the temperature dependence of the figure of merit to be found. Theoretical upper limit of maximum thermal efficiency of a given material with fixed cold and hot junction temperatures is considered and presented graphically. The general rules for material selection are discussed.