Electrochemical Synthesis and Nonvolatile Resistance Switching of Mn₃O₄ Thin Films
An electrodeposition method is introduced to produce crystalline films of Mn3O4 from aqueous solution. the films are electrodeposited potentiostatically from a solution of 0.2 M Mn(II) acetate at a pH of 6 and a deposition temperature of 80 °C. the anodic deposition is performed in the potential range of 0.275-0.350 V vs. Ag/AgCl/KCl(sat.). in this potential range the current efficiency is 100%. Both the stoichiometry and the morphology of the films can be controlled through the applied potential. Films deposited at a low overpotential grow with a  preferred orientation, columnar microstructure, and near-stoichiometric Mn(III)/Mn(II) ratio of 1.99. Films deposited at higher overpotential deposit with a near-random orientation, porous or powdery microstructure, and Mn(III)/Mn(II) ratio of 2.62. at potentials greater than 0.38 V, amorphous films of MnO2 are produced. the as-deposited Mn3O4 has a very high resistivity of 4.4 × 108 Ωcm. the electrodeposited Mn3O 4 films undergo unipolar, nonvolatile resistance switching. an Au/Mn3O4/AuPd cell can be reversibly switched between a high resistance state (30 MΩ) and a low resistance state (14.8 Ω) by applying SET and RESET voltages of the same polarity. SET and RESET times of approximately 2 and 50 ns were observed. Because of the large resistance contrast between the two states and the persistence of each state, Mn 3O4 is a candidate for future resistive random access memory (RRAM) devices.
J. A. Koza et al., "Electrochemical Synthesis and Nonvolatile Resistance Switching of Mn₃O₄ Thin Films," Chemistry of Materials, vol. 26, no. 15, pp. 4425-4432, American Chemical Society (ACS), Jan 2014.
The definitive version is available at https://doi.org/10.1021/cm5014027
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© 2014 American Chemical Society (ACS), All rights reserved.
01 Jan 2014