AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS1+EM-TuA

Paper SS1+EM-TuA1
Noncommutative Band Offset at @alpha@-Cr@sub 2@O@sub 3@/@alpha@-Fe@sub 2@O@sub 3@(0001) Heterojunctions

Tuesday, October 26, 1999, 2:00 pm, Room 606

Session: Oxides: Growth and Structure
Presenter: S.A. Chambers, Pacific Northwest National Laboratory
Authors: S.A. Chambers, Pacific Northwest National Laboratory
Y. Liang, Pacific Northwest National Laboratory
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We have measured the valence band discontinuity at artificially structured, epitaxial heterojunctions of @alpha@-Cr@sub 2@O@sub 3@(0001) and @alpha@-Fe@sub 2@O@sub 3@(0001) grown on @alpha@-Al@sub 2@O@sub 3@(0001) substrates. Oxygen-plasma-assisted molecular beam epitaxy was the growth technique, and band offsets were measured by core-level and valence-band photoemission. Layered film structures of these two materials maintain the in-plane lattice parameter of @alpha@-Fe@sub 2@O@sub 3@(0001). Thus, the @alpha@-Cr@sub 2@O@sub 3@(0001) layers are under a 2.3% tensile stress. The valence band offsets are 0.3±0.1 eV and 0.7±0.1 eV when the top layer is Fe@sub 2@O@sub 3@ and Cr@sub 2@O@sub 3@, respectively. The noncommutativity in band offset appears to be due to a growth-sequence-dependent interface dipole caused by different extents of intermixing for the two kinds of interfaces.