Properties of vanadium and tantalum granular oxide-metal tunnel junctions fabricated by electrochemical anodization

Localized electrochemical anodization has been used to prepare lateral vanadium (V) and tantalum (Ta) tunnel junctions. Electrical transport properties of these junctions were investigated at various temperatures ranging from 25 to 135 degrees C. A strong nonlinear current-voltage (I-V) curve indicates nonohmic transport which we believe is due to tunnel junction behavior. The metal-insulator transition was observed in the V junction at similar to 80 degrees C. The microstructure of these junctions explored by transmission electron microscope is consistent with metallic grains embedded in an oxide matrix and we therefore expect tunneling between the metallic grains to be the dominant transport mechanism. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3272944]