In this talk, I will review the grand challenges of the synthesis of metal oxides thin films containing elements of low oxidation potential. I will present our group’s effort to address these challenges using a new radical-based hybrid MBE approach. Using Stannate (BaSnO₃ and SrSnO₃) as a model material system, I will present a detailed growth study of epitaxial, phase-pure, stoichiometric (Ba,Sr)SnO₃ films using hexamethylditin, (CH₃)₆Sn₂ (HMDT) as a tin precursor, elemental solid source for Sr and Ba, and a rf plasma source for oxygen. Combined with a battery of structural characterization techniques, we will present a comprehensive electronic transport study of La-doped BaSnO₃ and SrSnO₃ and will discuss the important role of structural defects such as dislocations, and non-stoichiometry, and dopant concentration on electronic properties. We will also discuss different scattering mechanisms in La-doped BaSnO₃, which limits the room temperature electron mobility. Finally, we will present pathways to enhance electron mobilities towards high room temperature mobility oxide heterostructures using defect-managed thin films and interfaces.

Work supported by the NSF, and AFOSR YIP Program.