Room‐Temperature High‐Performance Photodetector and Phototransistor Based on PdSe2/ZnIn2S4 Alloy Heterojunctions

Abstract Various semiconductor devices have been developed based on 2D heterojunction materials owing to their distinctive optoelectronic properties. However, to achieve efficient charge transfer at their interface remains a major challenge. Herein, an alloy heterojunction concept is proposed. The sulfur vacancies in ZnIn 2 S 4 are filled with selenium atoms of PdSe 2 . This chemically bonded heterojunction can significantly enhance the separation of photocarriers, providing notable advantages in the field of photoelectric conversion. As a demonstration, a two‐terminal photodetector based on the PdSe 2 /ZnIn 2 S 4 heterojunction materials is fabricated. The photodetector exhibits stable operation in ambient conditions, showcasing superior performance in terms of large photocurrent, high responsivity (48.8 mA W −1 ) and detectivity (1.98 × 10 11 Jones). To further validate the excellent optoelectronic performance of the heterojunction, a tri‐terminal phototransistor is also fabricated. Benefiting from gate voltage modulation, the photocurrent is amplified to milliampere level, and the responsivity is increased to 229.14 mA W −1 . These findings collectively demonstrate the significant potential of the chemically bonded PdSe 2 /ZnIn 2 S 4 alloy heterojunction for future optoelectronic applications.