Design and Performance Evaluation of a Heterojunction GaAs/GaSb PC-TFET for Label-Free Biosensing Applications

This paper introduces a novel GaAs/GaSb polarity-controlled tunnel field-effect transistor (GaAs/GaSb PC-TFET)-based biosensor with high sensitivity for label-free biomolecule detection. The polarity-controlled concept is employed to create the drain/source region in the proposed structure, reducing fabrication complexity and cost. The electrical characteristics (drain current and threshold voltage) of the GaAs/GaSb PC-TFET biosensor change as different biomolecules are immobilized in the nano-cavity region. This study thoroughly investigates the ON-current sensitivity (S \(_{I_{ON}}\) $_{I_{\mathit{ON}}}^{}$ ) and threshold voltage sensitivity (S \(_{V_{Th}}\) $_{V_{\mathit{Th}}}^{}$ ) parameters of the proposed GaAs/GaSb PC-TFET biosensor. Findings indicate that the GaAs/GaSb PC-TFET biosensor exhibits higher S \(_{I_{ON}}\) $_{I_{\mathit{ON}}}^{}$ and S \(_{V_{Th}}\) $_{V_{\mathit{Th}}}^{}$ values ( \(1.53\times 10^{14}\) $1.53\times {10}^{14}$ and 0.79) as compared to recently reported similar FET/TFET-based biosensors. The efficiency of the proposed biosensor is further examined by studying the impact of the molecule’s charge density, non-ideality (steric hindrance and different fill factors), variation in cavity dimensions, temperature shifts, and noise on sensitivity. Additionally, selectivity, linearity, and transient response are analyzed to validate the proposed GaAs/GaSb PC-TFET biosensor’s abilities. The assessment of all investigated results reveals that the proposed GaAs/GaSb PC-TFET biosensor is a promising candidate for biosensing applications.