Silicon Nanotube Tunnel FET as a label free biosensor

Abstract

In this paper, we propose a Silicon Nanotube Tunnel FET-based biosensor in which ambipolar current is used as the sensitivity parameter. For fast switching low power consumption and steeper sub-threshold slope, aluminum (Al) is utilized as a source. A nanogap cavity-based tunnel FET biosensor is already demonstrated but Silicon Nanotube-based TFET biosensor is proposed for the first time. The result shows better sensitivity concerning the two different effects i.e., dielectric constant (k) and the charge of the biomolecules (positive or negative). For the practical realization of the band to band tunneling, the Kane model is employed in this work. The length of the cavity region is the main parameter to optimize the sensitivity. It shows superior results in dielectric modulation effects and higher ambipolar sensitivity even at lower concentrations of biomolecules. Band diagrams and electric field lines are analyzed to observe the performance of the biosensor. On increasing the value of the dielectric constant (k) from 5 to 20, the sensitivity of the biosensor is reduced by 3 times. It could be used in array-type screening and for DNA-based bio genre diagnostics. It has been observed that when we use the TFET as a biosensor, the leakage is minimum and the sensitivity is maximum.