A Novel Biosensing Approach: Improving SnS₂ FET Sensitivity with a Tailored Supporter Molecule and Custom Substrate

Abstract The exclusive features of two‐dimensional (2D) semiconductors, such as high surface‐to‐volume ratios, tunable electronic properties, and biocompatibility, provide promising opportunities for developing highly sensitive biosensors. However, developing practical biosensors that can promptly detect low concentrations of target analytes remains a challenging task. Here, a field‐effect‐transistor comprising n‐type transition metal dichalcogenide tin disulfide (SnS₂) is developed over the hexagonal boron nitride (h‐BN) for the detection of streptavidin protein (Strep.) as a target analyte. A self‐designed receptor based on the pyrene‐lysine conjugated with biotin (PLCB) is utilized to maintain the sensitivity of the SnS₂/h‐BN FET because of the π–π stacking. The detection capabilities of SnS₂/h‐BN FET are investigated using both Raman spectroscopy and electrical characterizations. The real‐time electrical measurements exhibit that the SnS₂/h‐BN FET is capable of detecting streptavidin at a remarkably low concentration of 0.5 pm, within 13.2 s. Additionally, the selectivity of the device is investigated by measuring its response against a Cow‐like serum egg white protein (BSA), having a comparative molecular weight to that of the streptavidin. These results indicate a high sensitivity and rapid response of SnS₂/h‐BN biosensor against the selective proteins, which can have significant implications in several fields including point‐of‐care diagnostics, drug discovery, and environmental monitoring.