Electrical conduction in V2O5-NiO-TeO2 glasses

Semiconducting oxide glasses in the V2O5-NiO-TeO2 system are prepared and the d.c, conductivity is studied at temperatures ranging from 333 to 475 K. The Seebeck coefficient measurements at temperatures from 375 to 475 K indicate the glasses to be n-type semiconducting, The d.c. conductivity ranges from 6.6 x 10(-7) to 1.3 x 10(-5) Scm(-1) at 405 K for V2O5 = 30-55 mol% and NiO = 10 mol%, and decreases with increasing NiO content, The conduction is confirmed to be due to a non-adiabatic small polaron hopping which occurs between V-ions in the glasses. The polaron bandwidth J is estimated to be J = 0.003-0.083 eV. The estimated hopping mobility is 8.2 x 10(-9) -4.9 x 10(-5) cm(2) V-1 s(-1) at 416 K and increases with increasing V2O5 content. The carrier density is evaluated to be 5.3 x 10(18) -7.3 x 10(20) cm(-3). (C) 1998 Elsevier Science S.A.