Calculation of distribution functions by exploiting the stability of the steady state

Solid State Communications, Vol. 6, pp. i

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v

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1968. Pergamon Press.

Printed in Great Britain

Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids “J. Phys. Chem. Solids (to be published)” should be cited in references to material quoted from this section prior to the publication of the relevant article.

1.

CANALISATION DES DEUTONS DANS LE QUARTZ F. Abel, G. Amsel, M. Bruneaux, E. d’Artemare (Groupe de Physique du Solide de 1’Ecole Normale Supêrieure Tour 23, 9 quai St. Bernard, Paris 5e France)

The channeling of deuterons in quartz was studied in order to separate the effects of the oxygen and silicon sub-lattices. The elastic scattering and the reaction ~O (d,p) ~ were observed at 900 keV. An automatic angular scanfling device was used and particular care was taken to reduce the effects on the crystal of the radiation damage induced by the beam. The extinction ratio of the yields was measured as a function of the beam angle with the c axis and of the depth in the crystal. It was found equal, near the surface, to 96. 8% for silicon and 89 ~ for oxygen. The corresponding widths at half minimum were 64’ and 36’. These experiments show that, in addition to elastic scattering, fluclear reactions should also be observed; this is especially easy at low energies with deuterons. It appears that the silicon strings tend to narrow the extinction curve and to increase the minimum yield associated with the oxygen strings. (Received 26 July 1968) 2.

TRAP DISTRIBUTION AND SPACECHARGE LIMITED CURRENTS IN ORGANIC CRYSTALS. ANTHRACENE 3. Sworakowski and K. Pigon (Department of Physical Chemistry, Wroclaw Technical University, Wybrzeze Wyspiansklego 27, Wroclaw, Poland)

A simplified theory of space-charge limited currents in a crystal with the “diffuse trap level” has been discussed. The equations

derived have been applied to experimental current voltage and current temperature characteristics in anthracene crystals. The hole trap band having the bottom at -0. 76 eV approximately has been found. —

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(Received 29 May 1968) (Revised 15 August 1968) 3~

CALCULATION OF DISTRIBUTION FUNCTIONS BY EXPLOiTING THE STABILITY OF THE STEADY STATE H.D. Rees (Royal Radar Establishment, Malvern, Worcestershire, Eng]and)

A numerical method is described for calculating distribution functions of free carriers In crystals from a knowledge of the scattering rates and applied fields. The stability of the steady state is exploited to derive an explicit expression for the distribution function without introducing any a priori assumptions about Its form. This expression can be evaluated by a convergent iterative process. A rate of scatter leaving the free carrier wave vector unaltered is defined. This scattering process has no physical consequence, but suitable choice of Its rate can make the numerical iteration straightforward. The technique is extended to accommodate scattering processes dependent on the distribution function and to analyse time dependent effects. Results are given of numerical calculations of distribution functions for free carriers in electric fields, taking Into account scattering processes including polar phonon and impurity scattering. (Received 3 June 1968) (Revlsed’23 August 1968) 4.

HOMOGENEITY RANGES AND Te2 PRESSURE ALONG THE THREE-PHASE CURVES FOR Bi2Te3(c) AND A 55-58 at % Te, PERITECTIC PHASE -