Planar Junctionless Field-Effect Transistor for Detecting Biomolecular Interactions

Area of Science:

• Biosensors and Nanotechnology
• Surface Chemistry
• Semiconductor Devices

Background:

• Label-free immunosensors are crucial for proteomics and diagnostics, offering high multiplexing and fast response.
• Field-effect transistor (FET) based sensors enhance sensitivity for detecting short peptides.

Purpose of the Study:

• To fabricate and characterize planar junctionless FET sensors for pH sensing.
• To evaluate the stability and surface properties of the fabricated FETs for biosensing applications.

Main Methods:

• Fabrication of planar junctionless FET sensors with SiO2 gate oxide.
• Characterization of sensor performance including voltage sensitivity and drain current drift.
• Theoretical modeling and simulation of surface states.
• Experimental verification of surface site immobilization (APTES, peptide, protein).

Main Results:

• The FET sensor exhibited voltage sensitivity ranging from 37.6 to 41.8 mV/pH at various drain currents.
• Stable sensor performance was observed with minimal drift over time (-0.45 to 0.01 pH/h).
• Experimental surface site immobilization values aligned with theoretical calculations.

Conclusions:

• The developed FET sensors demonstrate reliable pH sensing and stability.
• The findings support the potential of these FETs for detecting peptide-protein interactions in future diagnostic and therapeutic applications.