Light-Regulated Anti-Ambipolar Transport with Multi-Logic States in Metal-WSe2-Metal Transistor

With the advent of big data, multi-valued logic computing becomes an indispensable technology in the field of new micro-electronic devices. As a new concept attracting more attention in recent years, anti-ambipolar behavior shows its application potential in digital electronic and logic circuits. Here, the anti-ambipolar transistors (AATs) based on metal-WSe2-metal configuration with dual contact barriers is fabricated. Under light illumination, the photocurrent as function of gate voltage exhibits anti-ambipolar behavior with a distinct peak which can be varied with incident light power. The appearance of anti-ambipolar transport is attributed to both contact barrier and photo-excited carriers. The variation of the Fermi level in WSe2 regulated by gate voltage plays a key role in altering the dominant transport mechanism of the carrier type. This work proposes a new device concept that the photocarrier and barrier can induce an anti-ambipolar characteristic, guiding the new direction for the multi-valued logic/digital electronic applications.