Surface trap mediated electronic transport in biofunctionalized silicon nanowires

Area of Science:

• Nanotechnology
• Biosensing
• Biophysics

Background:

• Silicon nanowires (SiNWs) offer potential for electrical biosensing.
• Existing methods for detecting breast tumor markers have limitations in sensitivity and resolution.

Purpose of the Study:

• To develop and model a novel SiNW biosensor for detecting breast tumor markers.
• To investigate the "voltage gap" phenomenon as a detection parameter.

Main Methods:

• Fabrication of functionalized SiNWs using a top-down approach.
• Electrical characterization of SiNWs with and without biomarkers.
• Development of a physical model for surface electronic transport.

Main Results:

• SiNWs functionalized with probes exhibit a "voltage gap" in response to breast tumor markers.
• The voltage gap shows high-resolution dependence on biomarker concentration, achieving femtomolar sensitivity.
• A physical model accurately reproduces experimental I-V characteristics and explains the voltage gap behavior.

Conclusions:

• The voltage gap in SiNW biosensors is a novel and powerful parameter for sensitive biomarker detection.
• Dynamic recombination of nanowire surface states with bio-species charges is key to the voltage gap phenomenon.
• The developed model can predict I-V characteristics for various nanostructured devices and sensing applications.