Computational screening of reconfigurable van der Waals ferroelectric semiconductor heterojunctions for all-in-one optoelectronic devices

Reconfigurable optoelectronic devices based on two-dimensional (2D) van der Waals semiconductor heterojunctions (VSHs) are potential candidates for multifunctional applications in a single device. However, device multifunctionalities highly rely on VSHs with tunable band alignment and band offsets for achieving reconfigurable optoelectronic properties. Herein, we report a new class of 2D VSHs consisting of atomically thin ABP2X6-type ferroelectric (FE) semiconductors for the development of an all-in-one optoelectronic architecture based on high-throughput first-principles calculations and the nonequilibrium Green’s function method. Our results reveal that the polarization coupling of dual FE layers in the VSHs leads to multiple polarization states, allowing a sequential band-alignment evolution. Using CuInP2S6/AuInP2S6 VSHs as a prototype example, we demonstrate the heterojunction with reversible band-alignment transitions and tunable band offsets by modulating the polarization state of dual FE layers. This enables the device to achieve a theoretical tunneling electroresistance ratio (TER) of 106% between the interlayer FE and antiferroelectric (AFE) states at the bias voltage of 1.5 V, as well as positive and negative photoresponses. The FE-polarization-dependent band alignment and photoresponse of the heterojunction device can be used to implement in-sensor broadband convolutional processing for image recognition and reconfigurable optoelectronic logic operations including AND, OR, and XOR. These findings suggest huge potential of 2D FE VSHs for exploiting multifunctional optoelectronic device applications.