Suspended Graphene/LiTaO₃ Pyro-FeFETs for high-sensitivity uncooled infrared detection

Pyroelectric detectors are widely employed as uncooled infrared sensors. However, their conventional capacitor-based design generates weak electrical signals, requiring complex external amplification that limits integration density and signal-to-noise ratio. Here, we design and fabricate suspended pyroelectric-ferroelectric field-effect transistors (Pyro-FeFETs) featuring a monocrystalline lithium tantalate (LiTaO₃) gate dielectric and a graphene channel. Infrared-induced temperature variations alter the ferroelectric spontaneous polarization in LiTaO₃ due to perturbation of its internal dipole alignment. This ferroelectric polarization change effectively modulates the carrier concentration and conductivity of the graphene channel, resulting in a measurable current signal through the source-drain electrodes. Leveraging inherent nonlinear signal amplification of field-effect transistors and a suspended micro-bridge for enhanced thermal isolation, the device achieves uncooled blackbody infrared detection with a specific detectivity of 1.4 × 109 cm Hz1/2 W−1 and a response time of 51/38 ms. This integrated sensing-amplification architecture establishes a promising architecture for highly sensitive and compact uncooled infrared systems.