Large Pyroelectric Enhancement in Freestanding Epitaxial BaTiO3 Membranes on Si

TL;DR

This study demonstrates a significant enhancement of pyroelectric response in freestanding epitaxial BaTiO3 membranes transferred onto silicon, promising improved applications in infrared detection and energy management.

Contribution

The paper reports the integration of single crystalline BaTiO3 membranes on Si with a 4-34x increase in pyroelectric coefficient, a novel approach for enhancing ferroelectric responses in oxide electronics.

Findings

4x enhancement of pyroelectric coefficient at 30°C

34x enhancement at 60°C compared to clamped films

Effective pyroelectric coefficient of ~75 μC/m^2K at 30°C

Abstract

Ferroelectric membranes transferred onto arbitrary substrates provide reduced mechanical clamping at the interfaces that can diminish the effective polarization-rotation barrier offering a pathway to engineer larger electromechanical and thermally driven responses in oxide electronics. Here, we report integration of single crystalline thin film BaTiO3 (BTO) ferroelectric membrane on Si and demonstrate a 4x at 30C and 34x at 60C enhancement of pyroelectric coefficient compared to clamped films. The BTO membrane is grown epitaxially on a water-soluble Sr3Al2O6 sacrificial layer, released by selective dissolution, and transferred onto Si, yielding a strain-relaxed membrane with robust intrinsic polarization. Temperature dependent piezoresponse force microscopy (PFM) reveals pronounced thermally driven evolution of domain orientation, consistent with reduced barriers for dipolar modulation in the freestanding state. Variable-temperature Kelvin probe force microscopy (KPFM) quantifies an effective pyroelectric coefficient of ~75 uC/m^2K at 30C and 450 uC/m^2K at 60C with a detectivity of 40 m^2K^-1at room temperature. These results establish lead-free freestanding BTO membranes as a promising silicon-integrable platform for cryogen-free infrared detection and waste-heat energy management.