Bidirectional rectifier with gate voltage control based on Bi2O2Se/WSe2 heterojunction

Abstract

Two-dimensional (2D) WSe₂ has received increasing attention due to its unique optical properties and bipolar behavior. Several WSe₂-based heterojunctions exhibit bidirectional rectification characteristics, but most devices have a lower rectification ratio. In this work, the Bi₂O₂Se/WSe₂ heterojunction prepared by us has a type Ⅱ band alignment, which can vastly suppress the channel current through the interface barrier so that the Bi₂O₂Se/WSe₂ heterojunction device has a large rectification ratio of about 10⁵. Meanwhile, under different gate voltage modulation, the current on/off ratio of the device changes by nearly five orders of magnitude, and the maximum current on/off ratio is expected to be achieved 10⁶. The photocurrent measurement reveals the behavior of recombination and space charge confinement, further verifying the bidirectional rectification behavior of heterojunctions, and it also exhibits excellent performance in light response. In the future, Bi₂O₂Se/WSe₂ heterojunction field-effect transistors have great potential to reduce the volume of integrated circuits as a bidirectional controlled switching device.