High-performance α-Ga₂O₃/CdS quantum dots PEC photodetector based on the pyro-phototronic effect for optical communication

The photoelectrochemical (PEC) self-powered photodetector fabricated from α-Ga₂O₃ was limited by its bandgap to only absorbing light within the solar-blind ultraviolet (UV) range, and also exhibited relatively slow response characteristics. The pyro-phototronic effect (PPE) was demonstrated to play a crucial role in enhancing detector performance. In this study, an α-Ga₂O₃ nanorods/CdS quantum dots heterojunction PEC photodetector was successfully prepared through low-cost hydrothermal method and chemical bath deposition (CBD). Under the influence of the pyro-phototronic effect, a broadband response ranging from 220 nm (UV) to 700 nm (visible) was constructed. At the solar-blind UV wavelength of 254 nm, the photodetector has reached the optimal responsivity (R) and specific detectivity (D^*) of 0.99 mA/W and 3.62 × 10⁹ Jones, and the response times of this photodetector were promoted to 30 ms (rise) and 24 ms (fall). Furthermore, at the visible wavelength of 450 nm, the photodetector exhibited optimal R and D^* values of 1.48 mA/W and 6.76 × 10⁹ Jones, respectively. Based on the pyro-phototronic effect, three logic gate operations—“AND”, “OR”, and “NOT”—were successfully implemented, providing valuable insights for the application of PEC detectors in optical communication systems.