NI-IMPLANTED VITREOUS ELECTROLYTE AGASS2 - ESR, IONIC AND ELECTRONIC CONDUCTIVITY

Transport properties of AgAsS2 glassy solid electrolyte implanted with 60 keV nickel ions at dose of 10(17) Ni/cm2 were studied. The increase of ionic conductivity by 2.5 orders of magnitude and simultaneous activation energy decrease from 0.34 to 0.18 eV have been observed. The ionic conductivity enhancement is related to two-phase morphology of implanted layer which leads to formation of "infinite" percolation cluster with low-energy barriers for Ag+ ion motion. AgAsS2 glass reveals p-type electronic conductivity, sigma-p. Nickel ion implantation increases sigma-p by six orders of magnitude. The enhancement of hole transport has been explained involving small-polaron hopping between Ni2+ and Ni3+ ions. Temperature dependence of Ni3+ ESR line intensity is in agreement with polaron mechanism of sigma-p in Ni-containing chalcogenide glasses. ESR results showed also that charge state and coordination of impurity nickel ions in Ni-implanted and thermally-doped AgAsS2 glasses are identical.