Molybdenum doping of semiconducting vanadium phosphate glasses

The DC conductivity and dielectric properties of glasses of composition (70 ? x) V₂O₅ : x MoO₃ : 30 P₂O₅ have been measured as a function of temperature and frequency for O × 5 mol %. An increase in conductivity by two orders of magnitude is observed for 1 mol % MoO₃ and this is correlated with changes in activation energy and dielectric constant. The results can be explained in terms of small polaron theory, with the main interaction being through the local electronic polarizability at any site. The results indicate that percolation considerations have to be taken into account in describing the electrical properties of transition metal glasses.