Piezoresistive effects in controllable defective HFTCVD graphene-based flexible pressure sensor

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Flexible pressure sensors are crucial for various applications.
• Graphene's unique properties make it a promising material for sensor development.
• Defects in graphene can significantly alter its electronic properties.

Purpose of the Study:

• To investigate the piezoresistive effects of defective graphene in flexible pressure sensors.
• To demonstrate how graphene defect density influences sensor performance.
• To explore the tunability of sensor sensitivity via deposition temperature.

Main Methods:

• Graphene was synthesized using hot-filament thermal chemical vapor deposition (HFT-CVD) at varying temperatures (750, 850, 1000 °C).
• Defective graphene films were incorporated as sensing materials in flexible pressure sensor devices.
• The piezoresistive response was measured under applied gas pressures ranging from 0 to 50 kPa.

Main Results:

• A linear relationship between resistance change and applied gas pressure (0-50 kPa) was observed.
• Graphene deposited at lower temperatures (higher defect density) exhibited significantly higher sensitivity.
• The sensor with graphene deposited at 750 °C showed nearly four times the sensitivity compared to that deposited at 1000 °C.

Conclusions:

• Graphene defect density is a critical factor in determining the sensitivity of flexible pressure sensors.
• Controlling graphene deposition temperature allows for tuning sensor performance.
• Charge carrier scattering at defects and between graphene islands contributes to the enhanced piezoresistive effect.