Composition-dependent ferroelectricity in epitaxial AlYN
Rui Shen, Md Mehedi Hasan Tanim, Yutong Gan, Jiangnan Liu, Shubham Mondal, Yiran Li, Samuel Yang, Parag Deotare, Mackillo Kira, Kai Sun, Zetian MiWe 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.