【Device Papers】Solar-blind ultraviolet β-Ga₂O₃ phototransistor for logic and secure optical communication applications

      Researchers from the Jiangnan University have published a dissertation titled "Solar-blind ultraviolet β-Ga₂O₃ phototransistor for logic and secure optical communication applications" in Applied Physics Letters.

Abstract

      This work presents the fabrication of a high-performance solar-blind phototransistor based on a β-Ga₂O₃ thin film with a ring-shaped gate electrode, featuring a high-κ Al₂O₃ gate dielectric layer. Under 255 nm ultraviolet (UV) illumination, the device exhibits a high specific detectivity (D^*) of 5.26 × 10¹⁴ Jones, a photo-to-dark current ratio of 7.11 × 10⁵, a responsivity (R) of 4.01 A/W, and a UV-to-visible rejection ratio of 6 × 10². In addition, by using the gate voltage and solar-blind UV light as inputs and adjusting the source–drain voltage, switchable Not OR and Not AND (NAND) logic functions are achieved, with the source–drain current as the output. Based on the NAND logic operation, the gate voltage serves as a key to encrypt input signals, enabling secure optical communication. These results provide an appropriate approach for implementing secure optical communication based on Ga₂O₃ phototransistors.

DOI：https://doi.org/10.1063/5.0281687