Investigation of metal/V2O5 nanorod Ohmic contacts

In this work, V2O5 nanorods was prepared by thermal evaporation method followed by annealing at 550 degrees C in dry oxygen atmosphere for 60 min. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to investigate the structure and surface characteristics of V2O5 nanorods. To comparatively analyze and find the best Ohmic contact with optimum electrical properties, different metals (Al, Ag, Cu, Au, Ni, and Pt) with thickness of 200 nm each were deposited on V2O5 nanorods under a high vacuum using a sputtering system. To improve the Ohmicity of the metal/V2O5 contacts, annealing process was carried out at 300 degrees C in air atmosphere for 60 min. The Ohmic contact resistance of (metal/V2O5) interfaces can undervalue the actual contact resistance under standard operating conditions. Hence, the contact resistance, specific contact resistance, and the current transfer length were determined at room temperature, before and after annealing, by characterizing the current-voltage (I-V) relation using Transmission Line Method (TLM). Al metal was found to be the best for V2O5 Ohmic contact, because it produced the smallest resistivity, the lowest specific contact resistance, and the lowest current transfer length as compared to the other metals.