Graphene Field-Effect Transistors (GFETs)

Graphene Field-Effect Transistors (GFETs) — Precision Sensing at the Atomic Scale

Our Graphene Field-Effect Transistors (GFETs) are engineered for ultra-sensitive detection and high-performance electronic modulation, making them ideal for biosensing, chemical analysis, and advanced research applications. Built on the principles of electrostatic gating and quantum-scale conductivity, these three-terminal devices (source, drain, gate) use a graphene channel to transduce environmental changes into measurable electrical signals with exceptional fidelity.

🧠 How GFETs Work

GFETs operate by modulating the conductance of a graphene channel through an applied gate voltage (VGS). This voltage generates a transverse electric field across a thin dielectric layer, controlling the flow of charge carriers between the source and drain terminals. The result is a tunable drain current (IDS), which can be precisely adjusted based on the surrounding chemical or biological environment.

In biosensing applications, the adsorption of biomolecules onto the graphene surface shifts the Fermi level (EF), altering the carrier density and conductance. This mechanism enables label-free, real-time detection with high signal-to-noise ratios—thanks to graphene’s exceptional mobility and low electronic noise.

We support both:

• Back-Gated GFETs (BG-GFETs): Featuring CVD graphene transferred onto Si/SiO₂ substrates, modulated via back-gate voltage.
• Electrolyte-Gated GFETs (EG-GFETs): Using a reference electrode and electrolyte as the gate, ideal for liquid-phase biosensing with minimal leakage current.

⚙️ Fabrication & Materials

Our GFETs are available in channel sizes from 30 × 30 µm to 100 × 100 µm, with larger formats for high dynamic range and scalable production. We offer full customization of channel geometry, gate architecture, and substrate type.

Fabrication technologies include:

• Laser lithography for micro-scale patterning
• Metal shadow masking for cost-effective mass production
• E-beam lithography for nano-scale graphene channels

Metallization options:

• Gold, platinum, silver with titanium or chromium adhesion layers
• Deposited via PVD (Lesker systems) or e-beam evaporation

Encapsulation materials:

• SiO₂, silicon nitride, Al₂O₃
• Applied via FHR sputtering for robust passivation

🧪 Substrate Options & Integration

We fabricate GFETs on:

• Si/SiO₂ wafers
• Glass
• Flexible polyimide (Kapton)
• Transparent PET
• Custom substrates upon request

Planar gate electrodes (gold or silver chloride) are available for liquid-gated biosensing. Our chips are compatible with PDMS microfluidic chambers featuring inlet/outlet reservoirs, and we provide chip holders/adaptors for easy integration with measurement systems.

📐 Device Specifications

• Chip size: Standard 1 cm², customizable up to 4-inch wafers
• Substrate thickness: 675 µm
• Gate oxide thickness: 90 nm (customizable)
• Metallization: 100 nm Au-based contacts
• Field-effect mobility (back gating): >2000 cm²/V·s
• Dirac point (back gating): <20 V
• Dirac point (liquid gating): <0.9 V
• Max gate-source voltage (liquid gating in PBS): ±2 V
• Max gate-source voltage (back gating): ±50 V
• Max temperature rating: 150 °C
• Max drain-source current density: 10⁷ A/cm²

🔍 Quality Control & Characterization

Every GFET undergoes rigorous inspection and batch-level testing:

• Optical microscopy for structural integrity
• Raman spectroscopy for graphene quality
• Electrical characterization (back and liquid gating)
• AFM analysis for surface morphology

Our GFETs consistently deliver twice the transconductance and mobility compared to conventional market alternatives, with minimal intra-device variation—ensuring reproducibility and reliability across batches.

🌐 Applications

GFETs are ideal for:

• Graphene device research
• Chemical and gas sensing
• Bioelectronics and biosensing
• Optical and fluorescent detection
• Flexible and transparent sensor platforms
• Neuronal interfacing and cell monitoring