Hexagonal-phase single-crystal Gd₂O₃ is deposited on GaN in a molecular beam epitaxy system (see image). The dielectric constant is about twice that of its cubic counterpart when deposited on InGaAs or Si. The capacitive effective thickness of 0.5 nm in hexagonal Gd₂O₃ is perhaps the lowest on GaN-metal-oxide-semiconductor devices. The heterostructure is thermo dynamically stable at high temperatures and exhibits low interfacial densities of states after high-temperature annealing. The research was conducted at the NSRRC beamline BL17B.

W. H. Chang, C. H. Lee, Y. C. Chang, P. Chang, M. L. Huang, Y. J. Lee, C. H. Hsu, J. Minghuang Hong, C. C. Tsai, J. Raynien Kwo and Minghwei Hong