Fully epitaxial ferroelectric ScGaN grown on GaN by molecular beam epitaxy

We report on the ferroelectric properties of single-phase wurtzite ScGaN grown on GaN by plasma-assisted molecular beam epitaxy. Distinct ferroelectric switching behavior was confirmed by detailed electrical characterization. Coercive fields in the range of 2.0–3.0 MV/cm and large, retainable remnant polarization in the range of 60–120 μC/cm2 are unambiguously demonstrated for ScGaN epilayers with Sc contents of 0.31–0.41. Taking advantage of the widely tunable energy bandgap of III-nitride semiconductors, the demonstration of ferroelectricity in ScGaN, together with the recently reported ferroelectric ScAlN, will enable a broad range of emerging applications with combined functionality in ferroelectric, electronic, optoelectronic, photovoltaic, and/or photonic devices and systems.