Field emission from MoO3 nanobelts

Single-crystalline MoO3 nanobelts having an orthorhombic structure were prepared on a Si wafer via heating a Mo foil in air. The nanobelts were 50-300 nm wide and tens of nanometers thick. The nanobelt lengths lie in the [001] direction. Field-emission measurements showed that the threshold field decreased with the anode-sample separation increasing. Typically, a threshold field of 12.9 V/mum was determined at a spacing of 80 mum. The nanobelts exhibited a sharp increase in emission current density near the threshold field and, thus, reached a high current density at a relatively low field. Emission from both sharp corners and edges of the nanobelts is assumed to contribute to the high emission current. The high-current emission paired with high stability indicates that the prepared MoO3 nanobelt films are excellent field emitters. (C) 2002 American Institute of Physics.