Dielectric-Modulated Bulk-Planar Junctionless Field-Effect Transistor for Biosensing Applications

In this article, we have focused on the concept of junction-free transistor to propose and simulate the ultrathin dielectric modulated (DM) bulk-planar junctionless field-effect transistor (BP-JLFET) as a biosensor device. The proposed device is incorporated with a label-free detection of neutral (proteins, enzymes, streptavidin, and APTES) and charged [deoxyribonucleic acid (DNA)] biomolecules in terms of dielectric constant (K) and charge densities ( $\rho $ ). For the detection of the biomolecules, the nanocavity is formed by etching out the oxide underneath the gate dielectric at source end. The presence/absence of biomolecules has been detected by the factor of sensitivity with the immobilization of dielectric constant (K) and the charge density ( $\rho $ ) in the formed nanocavity. Moreover, the comparative study of the BP-JLFET, the dielectric-modulated tunnel field-effect transistor (DM-TFET), and the conventional dielectric-modulated field-effect transistor (DM-FET)-based biosensor in terms of their drain current ( ${\text I}_{ds}$ ) and the sensitivity have been carried out. From the study, it can be depicted that the BP-JLFET has higher sensitivity to sense the biomolecules compared to both the DM-TFET and the conventional DM-FET. Furthermore, we have also analyzed the noise characteristics for the simulated structures to measure the ability of the proposed device for sensing the biomolecules in the presence of noise.