Built-In Potential in Fe2O3-Cr2O3 Superlattices for Improved Photoexcited Carrier Separation

Tiffany C Kaspar; Daniel K Schreiber; Steven R Spurgeon; Martin E McBriarty; Gerard M Carroll; Daniel R Gamelin; Scott A Chambers

doi:10.1002/adma.201504545

Built-In Potential in Fe2O3-Cr2O3 Superlattices for Improved Photoexcited Carrier Separation

Adv Mater. 2016 Feb 24;28(8):1616-22. doi: 10.1002/adma.201504545. Epub 2015 Dec 17.

Authors

Tiffany C Kaspar¹, Daniel K Schreiber², Steven R Spurgeon¹, Martin E McBriarty¹, Gerard M Carroll³, Daniel R Gamelin³, Scott A Chambers¹

Affiliations

¹ Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99354, USA.
² Energy and Environment Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99354, USA.
³ Department of Chemistry, University of Washington, P.O. Box 1700, Seattle, WA, 98195-1700, USA.

PMID: 26679198
DOI: 10.1002/adma.201504545

Abstract

Hematite (α-Fe2 O3) is engineered to improve photoexcited electron-hole pair separation by synthesizing Fe2O3-Cr2O3 superlattices (SLs) with precise atomic control. The different surface terminations exhibited by Fe2O3 and Cr2O3 determine the hetero-junction interface structure and result in controllable, noncommutative band offset values. This controllable band alignment is harnessed to generate a built-in potential as large as 0.8 eV in Fe2 O3-Cr2O3 SLs.

Keywords: X-ray photoelectron spectroscopy; hematite; photoconductivity; potential; superlattices.