CONDUCTION MECHANISM IN THE PRE-SWITCHING STATE OF THIN-FILMS CONTAINING TE AS GE SI

Thin chalcogenide films from the Te-46-x As-32+x Ge-10 Si-12 (0 less t han or equal to x less than or equal to 5) system have been prepared b y thermal evaporation. The current-voltage characteristics in the temp erature range 305-423 K and thickness range 116-364 nm is ohmic in the lower field regime followed by non-ohmic behaviour in the higher volt age regime which has been satisfactorily explained by the anomalous Po ole-Frenkel effect. The dependence of ohmic current on temperature cor responds to a thermally activated process with the activation energy i ncreasing with increasing As content. The effect of composition and te mperature on the dielectric constant have been studied. The dielectric constant increases with decreasing temperature and increasing As cont ent.