Physically responsive field-effect transistors with giant electromechanical coupling induced by nanocomposite gate...

Area of Science:

• Materials Science
• Nanotechnology
• Electronics

Background:

• Physically responsive field-effect transistors (physi-FETs) are sensitive to physical stimuli, but separating sensing material responses from interference remains a challenge.
• Designing flexible physi-FETs with large electro-physical coupling effects using smart materials presents ongoing difficulties.

Purpose of the Study:

• To develop flexible organic FETs with enhanced electro-physical coupling by integrating barium titanate (BT) nanoparticle (NP) and poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) nanocomposite (NC) gate dielectrics.
• To introduce a novel alternating current (AC) biasing method for precise quantification of remnant polarization variations in NCs due to mechanical stimuli.

Main Methods:

• Direct integration of BT NP/P(VDF-TrFE) NC gate dielectrics into flexible organic FETs.
• Application of a new AC biasing method to analyze remnant polarization changes under mechanical stress.
• Characterization of physi-FETs under static mechanical stimuli to determine piezoelectric coefficients.

Main Results:

• Achieved a large electro-physical coupling effect in the developed flexible physi-FETs.
• Reported unprecedented giant, positive piezoelectric coefficients (d33) up to 960 pC/N in the BT/P(VDF-TrFE) NCs.
• Demonstrated precise extraction and quantification of tiny polarization variations caused by mechanical stimuli using the proposed AC biasing method.

Conclusions:

• The direct integration of BT NP/P(VDF-TrFE) NCs offers a promising route for high-performance flexible physi-FETs.
• The intrinsic positive piezoelectricity of BT NPs and P(VDF-TrFE) crystallites contributes to the observed giant piezoelectric coefficients.
• The novel AC biasing method enables accurate characterization of mechanical stimuli-induced polarization changes in NCs.