Engineering of the resistive switching properties in V_2O_5 thin film by atomic structural transition: Experiment and theory

摘要

Bipolar resistive switching has been reported in ITO/V2O5/ITO structures. Synthesized from the sol-gel process, the nanostructured V2O5 center dot nH(2)O xerogel thin film endures significant structural transition during the post-annealing step. The impact of the structural transition of the V2O5 film on the resistive switching properties is studied in this work. The switching voltage decreases from 6.5 V to 3.0 V when the annealing temperature increases from 220 degrees C to 280 degrees C and then increases up to 5.0 V at 350 degrees C. Above the annealing temperature of 350 degrees C, the reversible switching characteristics disappear. The thermogravimetric measurement shows that intercalated H2O molecules fully evaporate above 350 degrees C. X-ray diffraction shows that the xerogel phase gradually vanishes as the annealing temperature increases, and only alpha-V2O5 and beta-V2O5 exist at high annealing temperatures. Ab initio simulations are performed to evaluate the formation energies of the oxygen vacancy in xerogel, alpha-V2O5, and beta-V2O5 phases. The results are in good agreement with the experiments: the formation energy of the oxygen vacancy is significantly lower in xerogel than in alpha-V2O5 and beta-V2O5, enabling the occurrence of reversible switching when the xerogel phase exists in the sandwich structure. Published by AIP Publishing.