Epitaxial single-crystal thin films of MnxTi1 - xO2 - δ grown on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory

被引：8

作者：

Ilton, Eugene S. ^{[1
]}

Droubay, Timothy C. ^{[1
]}

Chaka, Anne M. ^{[1
]}

Kovarik, Libor ^{[1
]}

Varga, Tamas ^{[1
]}

Arey, Bruce W. ^{[1
]}

Kerisit, Sebastien N. ^{[1
]}

机构：

[1] Pacific NW Natl Lab, Richland, WA 99352 USA

来源：

SURFACE SCIENCE | 2015年 / 632卷

关键词：

Thin films; Pulsed laser deposition; Ab initio thermodynamics; Rutile; Manganese; DOPED TIO2; TITANIUM-DIOXIDE; ELECTRONIC-STRUCTURES; VACANCY FORMATION; RUTILE; MANGANESE; THERMODYNAMICS; HAUSMANNITE; TIO2(110); MINERALS;

D O I：

10.1016/j.susc.2014.10.013

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Epitaxial rutile-structured single-crystal MnxTi1 - xO2 (- delta) films were synthesized on rutile- (110) and -(001) substrates using pulsed laser deposition. The films were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and aberration-corrected transmission electron microscopy (ACTEM). Under the present conditions, 400 degrees C and PO2 = 20 mTorr, single crystal epitaxial thin films were grown for x = 0.13, where x is the nominal average mole fraction of Mn. In fact, arbitrarily thick films could be grown with near invariant Mn/Ti concentration profiles from the substrate/film interface to the film surface. In contrast, at x = 0.25, Mn became enriched towards the surface and a secondary nano-scale phase formed which appeared to maintain the basic rutile structure but with enhanced z-contrast in the tunnels, or interstitial sites. Ab initio thermodynamic calculations provided quantitative estimates for the destabilizing effect of expanding the beta-MnO2 lattice parameters to those of TiO2-rutile, the stabilizing effect of diluting Mn with increasing Ti concentration, and competing reaction pathways for surface oxide formation. (C) 2014 Elsevier B.V. All rights reserved.

引用

页码：185 / 194

页数：10

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