  A few-layer palladium diselenide (PdSe2) field effect transistor is studied
under external stimuli such as electrical and optical fields, electron
irradiation and gas pressure. We observe ambipolar conduction and hysteresis in
the transfer curves of the PdSe2 material unprotected and as-exfoliated. We
tune the ambipolar conduction and its hysteretic behavior in the air and pure
nitrogen environments. The prevailing p-type transport observed at room
pressure is reversibly turned into dominant n-type conduction by reducing the
pressure, which can simultaneously suppress the hysteresis. The pressure
control can be exploited to symmetrize and stabilize the transfer
characteristic of the device as required in high-performance logic circuits.
The transistor is immune from short channel effects but is affected by trap
states with characteristic times in the order of minutes. The channel
conductance, dramatically reduced by the electron irradiation during scanning
electron microscope imaging, is restored after several minutes anneal at room
temperature. The work paves the way toward the exploitation of PdSe2 in
electronic devices by providing an experiment-based and deeper understanding of
charge transport in PdSe2 transistors subjected to electrical stress and other
external agents.
