Composition-dependent ferroelectricity in epitaxial AlYN

Abstract

We report molecular beam epitaxy and ferroelectric properties of Al1-xYxN thin films with Y composition up to x = 41%. Structural characterization reveals that a wurtzite lattice structure is well preserved despite the large lattice distortions induced by increasing Y content. Both the coercive field and remanent polarization show a strong dependence on Y composition. The coercive field varies from 5.5 to 2.8 MV/cm with increasing Y compositions from 10% to 41%, whereas the remanent polarization is reduced from 140 to 70 μC/cm2. These properties are further compared with previously reported AlScN and GaScN. This study establishes AlYN as a tunable ferroelectric ultrawide-bandgap semiconductor for next-generation electronic, photonic, and electromechanical devices.