Electrically Tunable Piezotronic Transistor by Coupling Interface Polar Symmetry and Strain Gradient

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Piezotronics enable mechanical stimuli to shape electronic systems, crucial for IoT and wearables.
• Interface-dominated polarization limits performance tunability in current piezotronic sensors.

Purpose of the Study:

• To realize a tunable piezotronic effect by triggering bulk-dominated polarization in GaN.
• To overcome limitations of interface-dominated polarization for enhanced sensor applications.

Main Methods:

• Utilized a macroscale tip-induced strain gradient to induce bulk polarization in GaN.
• Investigated the role of interface polar symmetry and bulk piezo-charge shielding.
• Examined the effect of indenter size and spherical tip radii on tunability.

Main Results:

• Achieved a wide sensitivity tunability window (24,403) and high pressure sensitivity (223.2 meV·MPa⁻¹).
• Demonstrated ultrahigh strain sensitivity (1.43 × 10⁸) and exceptional mechanical durability (10,000 cycles).
• Showcased preserved electrical tunability under dynamic operation.

Conclusions:

• Uncovered cooperative roles of bulk polarization and interface symmetry in transport modulation.
• Established a viable strategy for continuous and wide-range performance tunability in mechanical sensors.
• Enriched piezotronic physics with a novel bulk-dominated polarization mechanism.