Effect of reduced dimensionality on the optical band gap of SrTiO3

Che Hui Lee, Nikolas J. Podraza, Ye Zhu, Robert F. Berger, Shaoping Shen, Michelle Sestak, Robert W. Collins, Lena F. Kourkoutis, Julia A. Mundy, Huiqiong Wang, Qingyun Mao, Xiaoxing Xi, Leonard J. Brillson, Jeffrey B. Neaton, David A. Muller, Darrell G. Schlom

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Abstract

The effect of dimensional confinement on the optical band gap of SrTiO3is investigated by periodically introducing one extra SrO monolayer every n SrTiO3layers. The result is the n 1-5 and 10 members of the Srn1TinO3n1Ruddlesden-Popper homologous series. Spectroscopic ellipsometry, optical transmission, and cathodoluminescence measurements reveal these Srn1TinO3n1phases to have indirect optical band gaps at room temperature with values that decrease monotonically with increasing n. First-principles calculations suggest that as n increases and the TiO6octahedra become connected for increasing distances along the c-axis, the band edge electronic states become less confined. This is responsible for the decrease in band gaps with increasing n (for finite n) among Srn1TinO3n1phases.
Original languageEnglish
Article number122901
JournalApplied Physics Letters
Volume102
Issue number12
DOIs
Publication statusPublished - 25 Mar 2013
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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