Controlling oxidation states in uranium oxides through epitaxial stabilization

The fabrication of single-crystal like epitaxial uranium oxides with controlled oxidation states through epitaxial stabilization has been demonstrated. To grow uranium oxides with controlled oxidation states, a polymer-assisted deposition (PAD) technique was used that does not necessitate an expensive vacuum technique or reactive organometallic actinide precursors as other solution techniques do. A polymer, Polyethylenimine (PEI), was used to control the desired viscosity for the process and to bind the metal ions to prevent premature precipitation and formation of metal oxide oligomers. A variety of uranium oxides with controllable phase and controlled oxidation states were achieved by pinning the crystal lattice in epitaxial films, by employing the advantage of the strong bonding across the interface between the substrate, LaAlO₃, and the film in heteroepitaxy.