A silicon carbide nanowire field effect transistor for DNA detection

Area of Science:

• Nanotechnology
• Biosensing
• Materials Science

Background:

• Label-free biosensing is crucial for real-time molecular detection.
• Silicon carbide (SiC) offers unique properties like chemical inertness and biocompatibility for electronic devices.
• Nanowire field-effect transistors (NWFETs) are highly sensitive platforms for detecting surface-bound molecules.

Purpose of the Study:

• To report the first label-free electrical detection of DNA molecules using silicon carbide nanowire field-effect transistors (SiC NWFETs).
• To investigate the performance of SiC NWFETs as DNA sensors, evaluating their sensitivity, selectivity, and stability.
• To establish a proof of concept for SiC-based NWFETs in biological sensing applications.

Main Methods:

• Growth of non-intentionally n-doped SiC nanowires (NWs) via a vapor-liquid-solid (VLS) mechanism.
• Fabrication of SiC NWFETs and functionalization with DNA probes using covalent coupling.
• Label-free electrical detection of DNA hybridization by monitoring drain current changes.

Main Results:

• SiC NWFETs functionalized with DNA probes showed a significant decrease in drain current after DNA grafting (22%) and hybridization (7%).
• Reference devices exhibited minimal current variation (±0.6%), confirming the specificity of the sensor response to DNA.
• Experiments demonstrated the selectivity, reproducibility, reversibility, and stability of the SiC NWFET-based DNA sensors.

Conclusions:

• Silicon carbide NWFETs are effective for label-free electrical detection of DNA.
• The observed current modulation is attributed to the field effect induced by DNA molecule charges.
• This work establishes SiC NWFETs as a promising platform for future advanced biosensor development.