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  Photoelectron emission from heterojunctions with intralayers: band-offset changes vs. band-bending effects

Horn, K., Moreno, M., Alonso, M., Höricke, M., Hey, R., Sacedón, J. L., et al. (2002). Photoelectron emission from heterojunctions with intralayers: band-offset changes vs. band-bending effects. Vacuum, 67(1), 115-123. doi:10.1016/S0042-207X(02)00198-7.

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 Creators:
Horn, Karsten1, Author           
Moreno, Maria, Author
Alonso, Maria, Author
Höricke, M., Author
Hey, R., Author
Sacedón, J. L., Author
Ploog, K. H., Author
Affiliations:
1Molecular Physics, Fritz Haber Institute, Max Planck Society, ou_634545              

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Free keywords: semiconductor heterojunctions; band offset; band bending; photoemission spectroscopy
 Abstract: The concept of "tuning" semiconductor heterojunction band offsets, by inserting a very thin layer of foreign atoms at the interface which acts as an "interface dipole", has received considerable attention. Modifications of the apparent valence-band offset, as measured by photoelectron spectroscopy (PES), have been indeed observed upon Si insertion at GaAs-AlAs interfaces, and have been interpreted as real band-offset changes. However, there is an alternative explanation of the results in terms of band-bending effects. Here, we present results of PES experiments designed to test these two interpretations. We have examined the effect of Si insertion at polar (1 0 0) and nonpolar (1 10) interfaces, and we have studied the insertion of Si (n-type) and Be (p-type) intralayers. Similar results are obtained for polar and nonpolar interfaces, and effects of opposite sign are observed for Si and Be intralayers. These results can be readily interpreted in terms of a band-bending profile modification upon Si or Be insertion. We analyse the implicit assumptions often made when using photoemission for band-offset determination, and the consequences of neglecting them. Photoemission experiments performed at different substrate temperatures, which make use of the surface photovoltage induced by the incident photons, permit a test of our proposed band profiles. From these data, we obtain evidence for a sample band bending, which is consistent with the room-temperature band profiles proposed. Hence, our results can be completely understood within a band-bending interpretation, without need to invoke the interpretation of intralayer action in terms of a "band-offset tuning" effect.

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Language(s): eng - English
 Dates: 2002-09-02
 Publication Status: Published in print
 Pages: -
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 Table of Contents: -
 Rev. Type: Peer
 Identifiers: eDoc: 8343
DOI: 10.1016/S0042-207X(02)00198-7
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Title: Vacuum
Source Genre: Journal
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Pages: - Volume / Issue: 67 (1) Sequence Number: - Start / End Page: 115 - 123 Identifier: -