MoS₂ Field-Effect Transistor for Next-Generation Label-Free Biosensors

Abstract

Biosensors based on field-effect transistors (FETs) have attracted much attention, as they offer rapid, inexpensive, and label-free detection. While the low sensitivity of FET biosensors based on bulk 3D structures has been overcome by using 1D structures (nanotubes/nanowires), the latter face severe fabrication challenges, impairing their practical applications. In this paper, we introduce and demonstrate FET biosensors based on molybdenum disulfide (MoS₂), which provides extremely high sensitivity and at the same time offers easy patternability and device fabrication, due to its 2D atomically layered structure. A MoS₂-based pH sensor achieving sensitivity as high as 713 for a pH change by 1 unit along with efficient operation over a wide pH range (3–9) is demonstrated. Ultrasensitive and specific protein sensing is also achieved with a sensitivity of 196 even at 100 femtomolar concentration. While graphene is also a 2D material, we show here that it cannot compete with a MoS₂-based FET biosensor, which surpasses the sensitivity of that based on graphene by more than 74-fold. Moreover, we establish through theoretical analysis that MoS₂ is greatly advantageous for biosensor device scaling without compromising its sensitivity, which is beneficial for single molecular detection. Furthermore, MoS₂, with its highly flexible and transparent nature, can offer new opportunities in advanced diagnostics and medical prostheses. This unique fusion of desirable properties makes MoS₂ a highly potential candidate for next-generation low-cost biosensors