2021/05/20 by Joseph Casamento, Ved Gund, Casamento, Joseph +26
Engineering · Physics and Astronomy · #Acoustic Wave Resonator Technologies #Applied Physics (physics.app-ph) #FOS: Physical sciences #GaN-based semiconductor devices and materials #Materials Science (cond-mat.mtrl-sci) #Ultrasonics and Acoustic Wave Propagation #cond-mat.mtrl-sci #physics.app-ph
paper · pdf · doi:10.48550/arxiv.2105.10114
openalex publication_date 2021/05/20 · arxiv created 2021/05/21 · arxiv updated 2021/05/24 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
Room temperature ferroelectricity is observed in lattice-matched ~18% ScAlN/GaN heterostructures grown by molecular beam epitaxy on single-crystal GaN substrates. The epitaxial films have smooth surface morphologies and high crystallinity. Pulsed current-voltage measurements confirm stable and repeatable polarization switching in such ferroelectric/semiconductor structures at several measurement conditions, and in multiple samples. The measured coercive field values are Ec~0.7 MV/cm at room temperature, with remnant polarization Pr~10 μC/cm2 for ~100 nm thick ScAlN layers. These values are substantially lower than comparable ScAlN control layers deposited by sputtering. Importantly, the coercive field of MBE ScAlN is smaller than the critical breakdown field of GaN, offering the potential for low voltage ferroelectric switching. The low coercive field ferroelectricity of ScAlN on GaN heralds the possibility of new forms of electronic and photonic devices with epitaxially integrated ferroelectric/semiconductor heterostructures that take advantage of the GaN electronic and photonic semiconductor platform, where the underlying semiconductors themselves exhibit spontaneous and piezoelectric polarization.