High Gain Solution‐Processed Carbon‐Free BiSI Chalcohalide Thin Film Photodetectors. (27th September 2021)

• Record Type: Journal Article
• Authors: Farooq, Sidra; Feeney, Thomas; Mendes, Joao O.; Krishnamurthi, Vaishnavi; Walia, Sumeet; Della Gaspera, Enrico; van Embden, Joel
• Is Part Of: Advanced functional materials. Volume 31:Number 52(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-27
• Subjects: bismuth -- chalcohalide -- oxyiodide -- photodetectors -- sulfiodide -- thin films; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202104788
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Chalcohalide semiconductors are an emergent class of materials for optoelectronics. Here, the first work on BiSI chalcohalide thin film photodetectors (PDs) is presented. An entirely new method for the fabrication of bismuth chalcohalide thin films (BiOI and BiSI) is developed. This method circumvents the use of any ligands or counter ions during fabrication and provides highly pure thin films free of carbon residues and other contaminants. When integrated into lithographically patterned lateral PDs these BiSI thin films show outstanding performances and high stability. The direct ≈1.55 eV bandgap of BiSI perfectly accommodates optical sensing over the full visible spectrum. The responsivity ( R ) of the BiSI PDs reaches 62.1 A W −1, which is the best value reported to date across chalcohalide materials of any type. The BiSI PDs display remarkable sensitivity to low light levels, supporting a broad operational detectivity ≈10 12 Jones over four decades in light intensity, with a peak specific detectivity (D*) of 2.01 × 10 13 Jones. The dynamics of photocurrent generation are demonstrated to be dominated by photoconductive gain. These results cement BiSI as an exciting candidate for high performance photodetector applications and encourage ongoing work in BiSX (X = Cl, Br, I) materials for optoelectronics. Abstract : Chalcohalides semiconductors are an emergent class of materials for optoelectronics. The hybrid composition of chalcohalides enables access to materials with improved stabilities, common to metal sulfides, but with the processability afforded by metal halides. In this article, bismuth sulfide iodide photodetectors with performances that surpass those of all other chalcohalide materials reported to date are presented.