Biological Sensing Using Vertical MoS₂-Graphene Heterostructure-Based Field-Effect Transistor Biosensors

Our study develops two configurations of MoS₂ and graphene heterostructures-MoS₂ on graphene (MG) and graphene on MoS₂ (GM)-to investigate biomolecule sensing in field-effect transistor (FET) biosensors. Leveraging MoS₂ and graphene's distinctive properties, we employ specialized functionalization techniques for each configuration: graphene with MoS₂ on top uses a silane-based method with triethoxysilylbutyraldehyde (TESBA), and MoS₂ with graphene on top utilizes 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE). Our research explores the application of MoS₂-Graphene heterostructures in biosensors, emphasizing the roles of synthesis, fabrication, and material functionalization in optimizing sensor performance. Through our experimental investigations, we have observed that doping MoS₂ and graphene leads to noticeable changes in the Raman spectrum and shifts in transfer curves. Techniques such as XPS, Raman, and AFM have successfully confirmed the biofunctionalization. Transfer curves were instrumental in characterizing the biosensing performance, revealing that GM configurations exhibit higher sensitivity and a lower limit of detection (LOD) compared to MG configurations. We demonstrate that GM heterostructures offer superior sensitivity and specificity in biosensing, highlighting their significant potential to advance biosensor technologies. This research contributes to the field by detailing the creation process of vertical MoS₂-graphene heterostructures and evaluating their effectiveness in accurate biomolecule detection, advancing biosensing technology.