Abstract
We describe the growth and properties of well-defined epitaxial TiO 2− x N x rutile for the first time. A mixed beam of atomic N and O radicals was prepared in an electron cyclotron resonance plasma source and Ti was supplied from a high-temperature effusion cell or an electron beam evaporator, depending on the required flux. A very high degree of structural quality is generally observed for films grown under optimized anion-rich conditions. N substitutes for O in the lattice, but only at the ∼1 at.% level, and is present as N 3−. Epitaxial growth of TiO 2 and TiO 2− x N x rutile prepared under anion-rich conditions is accompanied by Ti indiffusion, leading to interstitial Ti (Ti i ), which is a shallow donor in rutile. Our data strongly suggest that Ti i donor electrons compensate holes associated with substitutional N 2− (i.e., Ti(III) + N 2− → Ti(IV) + N 3−), leading to highly resistive or weakly n-type, but not p-type material. Ti 2p core-level line shape analysis reveals hybridization of N and Ti, as expected for substitutional N. Ti–N hybridized states fall in the gap just above the VBM, and extend the optical absorption well into the visible.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
