  We report the fabrication and performance of all-metallic three-terminal
devices with tantalum diselenide thin-film conducting channels. For this
proof-of-concept demonstration, the layers of 2H-TaSe2 were exfoliated
mechanically from single crystals grown by the chemical vapor transport method.
Devices with nanometer-scale thicknesses exhibit strongly non-linear
current-voltage characteristics, unusual optical response, and electrical
gating at room temperature. We have found that the drain-source current in
thin-film 2H-TaSe2-Ti/Au devices reproducibly shows an abrupt transition from a
highly resistive to a conductive state, with the threshold tunable via the gate
voltage. Such current-voltage characteristics can be used in principle for
implementing radiation-hard all-metallic logic circuits. These results may open
new application space for thin films of van der Waals materials.
