Accession Number : AD0716227

Title :   Dark Conduction Through Anthracene Crystals,

Corporate Author : QUEENSLAND UNIV BRISBANE (AUSTRALIA) DEPT OF CHEMISTRY

Personal Author(s) : Johnston,G. R. ; Lyons,L. E.

Report Date : 16 JUN 1970

Pagination or Media Count : 18

Abstract : Dark currents through anthracene crystals with silver paste electrodes were studied as functions of temperature, applied voltage, and time. Activation energies between 0.5eV and 2.9eV were measured, there being a definite correlation between log sigma(0) and E (the compensation effect). However, it was shown that the compensation effect arises from the calculation of sigma(0) and E, and not from a true linear free-energy relationship. As simple carrier generation mechanisms were inadequate to explain the temperature-dependence results, a model involving transitions between two limiting mechanisms was invoked and developed. The voltage-dependence results are shown to arise by a transition from SCL currents at low voltages, to barrier-limited currents (BLC) at higher fields, where the Schottky effect controls the current-voltage response. Vindication of the choice of this model is obtained from the calculated values of the parameters epsilon, the permittivity of anthracene; A, the Richardson constant; phi, the surface energy barrier for hole injection from silver paste into anthracene; and W(E)(Ag), the work function for silver paste electrodes. (Author)

Descriptors :   (*ANTHRACENES, ELECTRICAL PROPERTIES), ELECTRICAL CONDUCTIVITY, TEMPERATURE, SURFACES

Subject Categories : Crystallography
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE