  Palladium diselenide (PdSe2) is a recently isolated layered material that has
attracted a lot of interest for the pentagonal structure, the air stability and
the electrical properties largely tunable by the number of layers. In this
work, PdSe2 is used in the form of multilayer as the channel of back-gate
field-effect transistors, which are studied under repeated electron
irradiations. Source-drain Pd leads enable contacts with resistance below 350
kOhm um. The transistors exhibit a prevailing n-type conduction in high vacuum,
which reversibly turns into ambipolar electric transport at atmospheric
pressure. Irradiation by 10 keV electrons suppresses the channel conductance
and promptly transforms the device from n-type to p-type. An electron fluence
as low as 160 e-/nm2 dramatically change the transistor behavior demonstrating
a high sensitivity of PdSe2 to electron irradiation. The sensitivity is lost
after few exposures, that is a saturation condition is reached for fluence
higher than 4000 e-/nm2. The damage induced by high electron fluence is
irreversible as the device persist in the radiation-modified state for several
hours, if kept in vacuum and at room temperature. With the support of numerical
simulation, we explain such a behavior by electron-induced Se atom vacancy
formation and charge trapping in slow trap states at the Si/SiO_2 interface.
