Metal-Insulator Transition in the Vacuum Deposited Amorphous MoO3-TeO2 Films

Soma Mukherjee ； H. Sakata ； B. K. Chaudhuri

《Chinese Journal of Physics》 43卷3S期 (2005/06) Pp. 736-744

並列摘要

MoO3-TeO2 films prepared by vacuum deposition method from the corresponding bulk glass are found to show metal-insulator transition in the temperature range of 341–231 K depending on the film thickness. Interestingly, the corresponding bulk glass is semiconducting over the entire range of temperature (400–80 K). With the increase of MoO3 content, the peak temperature (Tp) of the metal insulator transition shifts to the lower temperature regime. In the high temperature semiconducting phase there is a critical temperature (Tc, say) above which a sharp rise of resistivity is observed with decrease of temperature. The value of Tc (355–307 K) decreases with the increase of MoO3 content. The semiconducting behavior above and below Tc could be well explained, respectively, with Mott’s 'small polaron' hopping conduction and variable range hopping (VRH) conduction mechanism. On the other hand, low temperature metallic conductivity (below Tp) is explained by using equation of the formρ =ρ0 +ρ2T^2 +ρ4.5T^4.5 (first and second term respectively, measure the electron-electron (el-el) and electron-phonon (el-ph) scattering contributions).