Information processing with optoelectronic devices provides an alternative way to efficiently process hybrid optical and electronic signals. Ferroelectric field‐effect transistors (FeFETs) can effectively respond to external optical and electrical stimuli by modulating their polarization states. Here, a 2D FeFET is demonstrated by the epitaxial growth of high‐quality 2D bismuth layered oxyselenide (Bi2O2Se) films on PMN‐PT(001) ferroelectric single‐crystal substrates. Upon switching the polarization direction of PMN‐PT, the authors realize in situ, reversible, and nonvolatile manipulation of the resistance of Bi2O2Se thin film (≈877%). The device simultaneously exhibits a polarization‐dependent photoresponse through visible light (λ = 405 nm) and infrared light (IR, λ = 980 nm) illumination. Combining optical stimuli with ferroelectric gating, it is demonstrated that the devices not only show nonvolatile memory and optoelectronic responses, but also show coincidence detection of visible and IR light. This work holds great potential in constructing new multiresponse and multifunction 2D‐FeFETs.

Integration of different functional materials into a device in which the physical properties can be tuned using an electric field in a reversible and nonvolatile manner is highly desired for the fabrication of compact and energy-efficient multifunctional electronic devices. The integration of In 2 O 3based semiconductor thin films with ferroelectric 0.71PbMg 1/3 Nb 2/3 O 3 -0.29PbTiO 3 (PMN-0.29PT) single crystals in ferroelectric-field-effect-transistor devices that allow for the tuning of carrier density, carrier type, Fermi level, and their related properties in a reversible and nonvolatile manner, is reported. Specifically, gating of In 2-x Cr x O 3 (x = 0, 0.02, 0.05, 0.08, 0.11) films with a PMN-0.29PT layer provides a means to reversibly tune and modulate the resistivity of the films up to an on-and-off ratio of 5.2 × 10 4 % in a nonvolatile manner at room temperature. Such resistivity modulation is associated with reversible and nonvolatile transformation of the carrier type between n-type and p-type due to polarization switching. Additionally, reversible switching of resistivity is realized utilizing DEME-TFSI ionic liquid as a top-gate material. These results demonstrate that electrical-voltage control of physical properties using PMN-xPT as both substrate and gating material provides a highly effective approach to study the carrier-density/type-related physical properties of semiconductor films.