Influence of an external electric field on the rapid synthesis of MoO_3 micro- and nanostructures by Joule heating of Mo wires

Abstract

The growth mechanism of layered alpha-MoO_3 nano- and microplates on the surface of Mo wires during Joule heating has been investigated by application of an external electric field to the current carrying wire. The observed rapid growth of the structures, involving enhanced diffusion processes associated to the intense electric current, is further enhanced by the external field leading to a near instantaneous formation of MoO_3 plates. Thermally assisted electromigration in the Mo wire with the additional effect of the electric field appears as a very time effective method to grow MoO_3 layered low dimensional structures. Other molybdenum oxide nanostructures, such as nanospheres and nanocrystallites with different shapes, have been found to grow by deposition from the Mo wire on the electrodes used to apply the external electric field. The growth on the electrodes takes place by a thermally assisted electric-field-driven process.