Synchrotron-radiation photoemission study of CdS/CuInSe2 heterojunction formation

Art J. Nelson, Steve Gebhard, Angus Rockett, Elio Colavita, Mike Engelhardt, Hartmut Höchst

Research output: Contribution to journalArticlepeer-review

Abstract

Synchrotron-radiation soft-x-ray photoemission spectroscopy was used to investigate the development of the electronic structure at the CdS/CuInSe2 heterojunction interface. CdS overlayers were deposited in steps on single-crystal p- and n-type CuInSe2 at 250C. Results indicate that the CdS grows in registry with the substrate, initially in a two-dimensional growth mode followed by three-dimensional island growth as is corroborated by reflection high-energy electron-diffraction analysis. Photoemission measurements were acquired after each growth in order to observe changes in the valence-band electronic structure as well as changes in the In 4d, Se 3d, Cd 4d, and S 2p core lines. The results were used to correlate the interface chemistry with the electronic structure at these interfaces and to directly determine the CdS/CuInSe2 heterojunction valence-band discontinuity and the consequent heterojunction band diagram. These results show that the Katnani-Margaritondo method is unreliable in determining offsets for heterojunctions where significant Fermi-level pinning may occur and where the local structure and chemistry of the interface depends strongly on the specific heterojunction.

Original languageEnglish (US)
Pages (from-to)7518-7523
Number of pages6
JournalPhysical Review B
Volume42
Issue number12
DOIs
StatePublished - 1990
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics

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