Vertical 1T'-WTe₂/WS₂ Schottky-Barrier Phototransistor with Polarity-Switching Behavior

In recent years, 2D reconfigurable phototransistors (RPTs) have been applied in broadband convolutional processing, retinomorphic hardware devices, and non-volatile memorizers. However, there has been a lack of investigation into all-2D Schottky junctions used in RPT with polarity control behavior. Herein, a vertically stacked multilayered WS2/WTe2 Schottky RPT is reported. The semimetal characteristics of 1T'-WTe2 is designed to form a built-in electric field of 69 meV across the heterojunction and WS2 exhibits gate-tunable characteristics. Therefore, reconfigurable rectifying behavior and self-driven bidirectional photo response can be achieved. The phototransistor possesses a gate-tunable rectification ratio ranging from 10(-2) to 10(5), and the corresponding logic half-wave rectifier shows excellent switchable rectifying states. Under 635 nm illumination, the responsivity can be adjusted from -1325 to 430 mA W(-1 )with reversed signs. Meanwhile, the maximum power conversion efficiency is 2.84%, and the specific detectivity is 1.47 x 10(12 )Jones. The device shows both negative and positive responsivity with linear gate dependence within a voltage window of 10 V. Impressively, nonvolatile photovoltaic performance can be demonstrated by reversing short-circuit current and open-circuit voltage by applying and releasing pulsed gate voltage. Finally, reconfigurable polarization behavior, single-pixel imaging, and the optical logic circuit are applicable to the heterostructure.