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Title: Band offsets for mismatched interfaces. The special case of ZnO on CdTe (001)

High-quality planar interfaces between ZnO and CdTe would be useful in optoelectronic applications, but appear difficult to achieve given the rather different crystal structures (CdTe is zinc blende with cubic lattice constant a = 6.482 Å, ZnO is hexagonal wurtzite with a = 3.253 Å and c = 5.213 Å.) However, ZnO has been reported to occur in some epitaxially stabilized films in the zinc blende structure with an fcc primitive lattice constant close to the hexagonal a value. Observing that this value equals half of the CdTe cubic lattice constant to within 1%, we propose that (001)-oriented cubic ZnO films could be grown epitaxially on a CdTe (001) surface in an R45° √2 x √2 configuration. Many terminations and alignments (in-plane fractional translations) are possible, and we describe density-functional total-energy electronic-structure calculations on several configurations to identify the most likely form of the interface, and to predict valence-band offsets between CdTe and ZnO in each case. Growth of ZnO on Te-terminated CdTe (001) is predicted to produce small or even negative (CdTe below ZnO) valence band offsets, resulting in a Type I band alignment. Growth on Cd-terminated CdTe is predicted to produce large positive offsets for a type IImore » alignment as needed, for example, in solar cells. We also describe recent experiments that corroborate some of these predictions.« less
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  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0734-2101; 34725
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 31; Journal Issue: 6
American Vacuum Society
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org:
Country of Publication:
United States
47 OTHER INSTRUMENTATION; Environmental Molecular Sciences Laboratory