title: Strain Dependent Electronic Structure and Band Offset Tuning at Heterointerfaces of ASnO3(A=Ca, Sr, and Ba) and SrTiO3.
abstract: The valence band (VB) electronic structure and VB alignments at heterointerfaces of strained epitaxial stannate ASnO3(A=Ca, Sr, and Ba) thin films are characterized using in situ X-ray and ultraviolet photoelectron spectroscopies, with band gaps evaluated using spectroscopic ellipsometry. Scanning transmission electron microscopy with geometric phase analysis is used to resolve strain at atomic resolution. The VB electronic structure is strain state dependent in a manner that correlated with a directional change in Sn-O bond lengths with strain. However, VB offsets are found not to vary significantly with strain, which resulted in ascribing most of the difference in band alignment, due to a change in the band gaps with strain, to the conduction band edge. Our results reveal significant strain tuning of conduction band offsets using epitaxial buffer layers, with strain-induced offset differences as large as 0.6 eV possible for SrSnO3. Such large conduction band offset tunability through elastic strain control may provide a pathway to minimize the loss of charge confinement in 2-dimensional electron gases and enhance the performance of photoelectrochemical stannate-based devices.
authors.affiliation: Fujitsu Laboratories, Atsugi, Kanagawa-ken, Japan.
authors.forename: John D
authors.initials: JD
authors.lastname: Baniecki
authors.affiliation: Fujitsu Laboratories, Atsugi, Kanagawa-ken, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: Innovator and Inventor Development Platform, Tokyo Institute of Technology,4259-J3-21 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Dan
authors.initials: D
authors.lastname: Ricinschi
authors.affiliation: Institute of Mechanics, Materials and Civil Engineering, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Van Overmeere
authors.affiliation: Fujitsu Laboratories, Atsugi, Kanagawa-ken, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Aso
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Miyata
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Fujimura
authors.affiliation: School of Materials Science and Engineering, University of New South Wales, Sydney, 2052, Australia.
authors.forename: Ronald
authors.initials: R
authors.lastname: Maran
authors.affiliation: Fujitsu Laboratories, Atsugi, Kanagawa-ken, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Anazawa
authors.affiliation: School of Materials Science and Engineering, University of New South Wales, Sydney, 2052, Australia.
authors.forename: Nagarajan
authors.initials: N
authors.lastname: Valanoor
authors.affiliation: Fujitsu Laboratories, Atsugi, Kanagawa-ken, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Imanaka