Impurity conduction in synthetic semiconducting diamond

Abstract

Electrical conductivity and Hall effect measurements have been made on a series of synthetic p-type semiconducting diamonds in the temperature range 80 to 450K. The dominant conductivity mechanism at low temperatures is shown to be impurity conduction, and effects have been isolated due both to impurity-band conduction and to hopping transport between neutral and ionized acceptor centres. The activation energies associated with the latter processes are much lower than the acceptor ionization energy, and the variation with temperature of the onset of impurity conduction as a function of the neutral acceptor concentration accounts for the wide range of activation energies reported for synthetic diamonds by previous authors.