Memristive effects due to charge transfer in graphene gated through ferroelectric CuInP2S6

Ferroelectricity at the nanometre scale can drive the miniaturisation and wide application of ferroelectric devices for memory and sensing applications. The two-dimensional van der Waals (2D-vdWs) ferroelectrics CuInP2S6 (CIPS) has attracted much attention due to its robust ferroelectricity found in thin layers at room temperature. Also, unlike many 2D ferroelectrics, CIPS is a wide band gap semiconductor, well suited for use as a gate in field-effect transistors (FETs). Here, we report on a hybrid FET in which the graphene conducting channel is gated through a CIPS layer. We reveal hysteresis effects in the transfer characteristics of the FET, which are sensitive to the gate voltage, temperature and light illumination. We demonstrate charge transfer at the CIPS/graphene interface in the dark and under light illumination. In particular, light induces a photodoping effect in graphene that varies from n- to p-type with increasing temperature. These hybrid FETs open up opportunities for electrically and optically controlled memristive devices