Isotropic conduction and negative photoconduction in ultrathin PtSe2 films
Urban, Francesca, Gity, Farzan, Hurley, Paul K., McEvoy, Niall, Di Bartolomeo, Antonio
Abstract
PtSe2 ultrathin films are used as the channel of back-gated field-effect transistors that are investigated at different temperatures and under super-continuous white laser irradiation. The temperature-dependent behavior confirms the semiconducting nature of multilayer PtSe2, with p-type conduction, a hole field-effect mobility up to 40 cm2 V−1 s−1, and significant gate modulation. Electrical conduction measured along different directions shows isotropic transport. A reduction of PtSe2 channel conductance is observed under exposure to light. Such a negative photoconductivity is explained by a photogating effect caused by photo-charge accumulation in SiO2 and at the Si/SiO2 interface.