Very high thermal to electric conversion efficiencies have been reported previously with thermal diode structures in which a thin n-type emitter layer is formed on the hot side of a thick near-intrinsic thermoelectric semiconductor. The figure of merit derived from direct measurements of electrical parameters and heat flow is increased by as much as a factor of eight. The question of what physical mechanisms are involved has been of interest since the initial observations of the effect. We have conjectured that the short-circuit current injection in these experiments is due to a second-order thermionic injection mechanism. More recently, we proposed that the open-circuit voltage comes about due to the presence of a p-type blocking layer between the emitter and the near-intrinsic bulk region. The experiments reported here show that a p-type blocking layer is required for the effect, and the dependence of conversion efficiency on the blocking layer concentration and width is studied. The results are generally consistent with calculations done so far based on a nonlocal generalized Onsager-type transport model.
\ Ill(Jde1 theory of the influence of particles interaction in pliisrna on its composition and optical properties is developed.The interaction of charged particles in plasma reduces the ionization energy of atonis and ions. The action of internal microfields in plasma on atoms and ions reduces the statistical weight of electron levels which affects the populations of excited states. The latter effect lcads to a n cffectivc. cutoff of partition functions and determines the behaviour of optical properties of plasnia (of absurption coefficicnt and ernissivity) a t increased niimber dcnsities of charged particles.The formulas are obtained for enleulation of the continuous and discrete spectrum in plasma taking into account the particles interaction. A non-monotonic dependence of optical plasma density upon number density of charged particles is quantitatively explained. A satisfactory ngreciiient is obtained with a large number of experimental dnta some of which were considered to be contradictory.The method developed can be used for calculations in the field of atomic spectroscopy and low-temperature plasma physics including increased densities of charged particles. The use of the formulns obtained in plasma diagnostics will enable one to avoid considerable errors.Electron structure of atoms, intensities and half-widths of spectral lines, photoionization cross sections of bound states of isolated particles are known sufficiently well, however, the spectral absorption coefficient or emissivity calculated without taking into account particles interaction in plasma often are not in agreement with experiments. The discrepancy exceeds a factor of two or more a t increased densities. Until now there has been in the literature no adeqiiate theory satisfactorily describing the influence of the interaction on the properties of real atoms.Below a model theory is presented which enables one to take into account the tlistrrrbing influence of charged particles in plasma on its composition. thermophysical and, principally, optical properties. A careful comparison with arailable experimental data i. ; carried out. A satisfactory agreement reached there allows one to recommend tlic developed model for its use in practical computations and in plasma diagnostics. USSR, 1981, P a r t I, p. 339-340.(1966)
485.Recelved October 31, 1RP3
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.