High-responsivity PtSe2 photodetector enhanced by photogating effect

Platinum diselenide (PtSe2), a recently rediscovered two-dimensional transition metal dichalcogenide, has attracted immense attention in the optoelectronic field due to its tunable bandgap, ultrastability, and high electron mobility. However, the applications of PtSe2 photodetectors are seriously restricted by their low responsivity. In this work, a high-responsivity (5 × 104 A/W) PtSe2 photodetector is obtained by exploiting a photogating effect; this is induced by the hole-trapping states, which are attributed to Se vacancies. Moreover, a gate-tunable transition between the positive and negative photoconductances is observed under light illumination. A theoretical calculation based on the Boltzmann transport theory is performed to explain the carrier transport of PtSe2, considering the contributions of charged impurity, acoustic phonon, and polar optical phonon scattering.