Solution-processed ZnBi2S4 polycrystalline thin films for low noise photodetection

Abstract

Chalcogenide semiconductors have emerged as promising candidates for optoelectronic applications due to their unique properties, including low toxicity, fabrication cost, superior stability, and decent charge transport properties. In particular, Bi-based chalcogenides, e.g., AgBiS2 and Bi2S3, have been extensively studied for photovoltaic and photodetection applications. AgBiS2 exhibits relatively high photoconversion efficiency but large dark current. On the other hand, Bi2S3 possesses relatively low dark current but limited charge transport. In this study, we introduce zinc ion within the Bi2S3 precursor and fabricate phase-pure ZnBi2S4 semiconductor, which showed improved optoelectronic properties. The fundamental properties of ZnBi2S4 are fully characterized, and we also demonstrated photodiodes with excellent device performance, suggesting great potential for photodetection.