title: Growth control of oxygen stoichiometry in homoepitaxial SrTiO3 films by pulsed laser epitaxy in high vacuum.
abstract: In many transition metal oxides, oxygen stoichiometry is one of the most critical parameters that plays a key role in determining the structural, physical, optical, and electrochemical properties of the material. However, controlling the growth to obtain high quality single crystal films having the right oxygen stoichiometry, especially in a high vacuum environment, has been viewed as a challenge. In this work, we show that, through proper control of the plume kinetic energy, stoichiometric crystalline films can be synthesized without generating oxygen defects even in high vacuum. We use a model homoepitaxial system of SrTiO3 (STO) thin films on single crystal STO substrates. Physical property measurements indicate that oxygen vacancy generation in high vacuum is strongly influenced by the energetics of the laser plume, and it can be controlled by proper laser beam delivery. Therefore, our finding not only provides essential insight into oxygen stoichiometry control in high vacuum for understanding the fundamental properties of STO-based thin films and heterostructures, but expands the utility of pulsed laser epitaxy of other materials as well.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Ho Nyung
authors.initials: HN
authors.lastname: Lee
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.|Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Sung S
authors.initials: SS
authors.lastname: Ambrose Seo
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.|Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Woo Seok
authors.initials: WS
authors.lastname: Choi
authors.affiliation: Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Rouleau
references.citation: Nature. 2004 Aug 12;430(7001):758-61
references.pmid: 15306803
references.citation: Nat Mater. 2008 Nov;7(11):855-8
references.pmid: 18849974
references.citation: Nature. 2002 Sep 26;419(6905):378-80
references.pmid: 12353030
references.citation: Science. 1994 Dec 2;266(5190):1540-2
references.pmid: 17841713
references.citation: Nature. 2005 Jan 27;433(7024):395-9
references.pmid: 15674286
references.citation: Adv Mater. 2012 Dec 18;24(48):6423-8
references.pmid: 23034879
references.citation: Nat Mater. 2010 Jun;9(6):482-4
references.pmid: 20364139
references.citation: Nature. 2004 Aug 5;430(7000):620-1
references.pmid: 15295580
references.citation: Nat Commun. 2015 Jun 24;6:7424
references.pmid: 26104684
references.citation: Phys Rev Lett. 2007 May 25;98(21):217602
references.pmid: 17677807
references.citation: Phys Rev Lett. 2010 May 14;104(19):197601
references.pmid: 20866998
references.citation: Phys Rev Lett. 2007 May 25;98(21):216803
references.pmid: 17677799