Design of a label-free biosensor based on dielectrically modulated GeSn heterojunction vertical TFET

In this manuscript, a Label free biosensor based on dielectrically modulated GeSn heterojunction Vertical Tunnel Field-Effect transistor has been designed and analyzed. The performance of Label-free biosensor has been checked for the detection of several biological molecules viz. Protein, Uricase, Keratin and Gelatin. To perceive the biomolecules, a nano-gap cavity of 5 nm has been formed under the metal gate layer on the both sides. Due to the alteration in the device’s effective dielectric constant caused by the introduction of biomolecules, a considerable shift in different electrical metrics such as drain current, electric field, electron band-to-band tunneling (eBTBT) rate, threshold voltage, and drain current sensitivity have been detected. Further, sensitivity of the biosensor has been investigated for both neutral and charged biomolecules. Charged biomolecule with dielectric constant of K = 12 is studied for various positive and negative charge densities. Irregular/non-uniform hybridization contours such as: decreasing, increasing, concave and convex step contours are also evaluated for Gelatin (K = 12) biomolecule. The device’s sensing capability is assessed in terms of different DC performance metrics. For the Gelatin biomolecule at K = 12, the maximum ON-current and OFF-current for the biosensor are 6.85 × 10^–5 _A/µm and 3.99 × 10^–16 _A/µm respectively. The suggested biosensor yielded subthreshold swing and drain current sensitivity measurements of 24.45 mV/dec and 5.87 × 10⁶ respectively. As the relative permittivity difference between the biomolecules is larger than the selectivity of the biomolecules will also be higher. Finally, the suggested biosensor device is benchmarked against other published research, and has been demonstrated to produce better sensitivity.