Graphene Field-Effect Transistor for Biomolecular Recognition Essay

The collective vibrational motions of biomolecules at the terahertz/far infrared frequencies can be employed as a unique fingerprint for molecular recognition. The conventional far infrared spectroscopy methods show very weak absorption signals of biomolecules. At present, a detection method is needed with enhanced sensitivity that can be utilized to identify biomolecules in dilute concentrations required for immunological diagnostic in clinical applications. We fabricate graphene field-effect transistor devices for biomolecular detection at the terahertz frequencies. The intensity of the collective vibrational modes of biomolecules is efficiently enhanced in a desired frequency range by tuning the gate voltage. Fourier transform infrared spectroscopy is used as a simultaneous authentication of vibrational modes. The device can measure a low concentration of biomolecules with plasmons induced amplification factor of ∼ 40 as compared to FTIR signals.