Electrical Properties of Vanadium Pentoxide

摘要

The dc conductivity of single crystals of vanadium pentoxide was measured in the three crystallographic directions. The temperature range examined was -165C to + 25C. The activation energy of the conduction process was isotropic and found to be .56 ev. The conductivity was anisotropic. Measurements of the Hall effect were attempted with a dc and ac apparatus, but the signal was too low to be observed. However, an upper limit of 71 cu cm/coulomb for the Hall coefficient was calculated, and the upper limit computed for the mobility was .4 sq cm/volt sec. A model is proposed for the conduction mechanism. It suggests that the electrical conduction is a two-step process. The electron is ionized from a V(4+)-oxygen-vacancy center and then moves through the lattice via polaron movement. This model accounts for the isotropy of the activation energy and also the anisotropy of the conductivity. (Author)