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

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 ZnIn2S4 are filled with selenium atoms of PdSe2. 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 PdSe2/ZnIn2S4 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 × 1011 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 PdSe2/ZnIn2S4 alloy heterojunction for future optoelectronic applications. PdSe2/sulfur vacancies‐ZnIn2S4 (Sv‐ZIS) alloy heterojunction connected by chemical bonding is proposed for realizing efficient photogenerated carrier transfer. Thanks to the tight interfacial contact and enhanced light absorption of the heterojunction, the as‐fabricated photodetectors exhibit excellent performance in terms of photocurrent, switching ratio, responsivity, and detectivity. Moreover, the transistor with gate voltage modulation capability amplifies the photocurrent to the milliampere level and increases the responsivity.