  Recent experiments on layered {\alpha}-In2Se3 have confirmed its
room-temperature ferroelectricity under ambient condition. This observation
renders {\alpha}-In2Se3 an excellent platform for developing two-dimensional
(2D) layered-material based electronics with nonvolatile functionality. In this
letter, we demonstrate non-volatile memory effect in a hybrid 2D ferroelectric
field effect transistor (FeFET) made of ultrathin {\alpha}-In2Se3 and graphene.
The resistance of graphene channel in the FeFET is tunable and retentive due to
the electrostatic doping, which stems from the electric polarization of the
ferroelectric {\alpha}-In2Se3. The electronic logic bit can be represented and
stored with different orientations of electric dipoles in the top-gate
ferroelectric. The 2D FeFET can be randomly re-written over more than $10^5$
cycles without losing the non-volatility. Our approach demonstrates a protype
of re-writable non-volatile memory with ferroelectricity in van de Waals 2D
materials.
