Sensitivity enhanced tunable plasmonic biosensor using two-dimensional twisted bilayer graphene superlattice

Abstract This study theoretically demonstrated an insight for designing a novel tunable plasmonic biosensor, which was created by simply stacking twisted bilayer graphene (TBG) superlattice onto gold thin film. To achieve ultrasensitive biosensing, the biosensor modulated Goos–Hänchen (GH) shift. Interestingly, our proposed exhibited biosensing ability, largely depending on angle. When relative angle optimized to be 55.3°, such configuration: 44 nm Au film/1-TBG could produce ultralow reflectivity of 2.2038 × 10 −9 and ultra-large GH shift 4.4785 4 µm. For small refractive index (RI) increment 0.0012 RIU (refractive unit) in sensing interface, optimal configuration offer ultra-high detection sensitivity 3.9570 7 µm/RIU. More importantly, theoretical possibility quantitatively monitoring severe acute respiratory syndrome coronavirus (SARS-CoV-2) human hemoglobin. Considering extremely RI change as little 3 −7 RIU, good linear response between concentration SARS-CoV-2 changes differential studied. SARS-CoV-2, interval obtained from 0 2 nM. hemoglobin, range achieved 0.002 g/L. Our work will important develop TBG-enhanced biosensors detecting microorganisms biomolecules biomedical application.