Interface reactions and Kirkendall voids in metal organic vapor-phase epitaxy grown Cu(In,Ga)Se2 thin films on GaAs

C. H. Lei; A. A. Rockett; I. M. Robertson; N. Papathanasiou; S. Siebentritt

doi:10.1063/1.2397282

Interface reactions and Kirkendall voids in metal organic vapor-phase epitaxy grown Cu(In,Ga)Se₂ thin films on GaAs

C. H. Lei, A. A. Rockett, I. M. Robertson, N. Papathanasiou, S. Siebentritt

Research output: Contribution to journal › Article › peer-review

Abstract

Cu (In1-x Gax) Se2 (CIGS) films were grown on (001) GaAs at 570 or 500 °C by means of metal organic vapor-phase epitaxy. All films were Cu-rich [Cu (In+Ga) >1] with pseudomorphic Cu2 Se second phase particles found only on the growth surface. During growth, diffusion of Ga from the substrate and vacancies generated by the formation of CIGS from Cu2 Se at the surface occurred. The diffusion processes lead to the formation of Kirkendall voids at the GaAs/CIGS interface. Transmission electron microscopy and nanoprobe energy dispersive spectroscopy were used to analyze the diffusion and void formation processes. The diffusivity of Ga in CIGS was found to be relatively low. This is postulated to be due to a comparatively low concentration of point defects in the epitaxial films. A reaction model explaining the observed profiles and voids is proposed.

Original language	English (US)
Article number	114915
Journal	Journal of Applied Physics
Volume	100
Issue number	11
DOIs	https://doi.org/10.1063/1.2397282
State	Published - 2006
Externally published	Yes

ASJC Scopus subject areas

General Physics and Astronomy

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10.1063/1.2397282

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@article{8b7baeddb27d465ca0ae4f2e5d4fe5e4,

title = "Interface reactions and Kirkendall voids in metal organic vapor-phase epitaxy grown Cu(In,Ga)Se2 thin films on GaAs",

abstract = "Cu (In1-x Gax) Se2 (CIGS) films were grown on (001) GaAs at 570 or 500 °C by means of metal organic vapor-phase epitaxy. All films were Cu-rich [Cu (In+Ga) >1] with pseudomorphic Cu2 Se second phase particles found only on the growth surface. During growth, diffusion of Ga from the substrate and vacancies generated by the formation of CIGS from Cu2 Se at the surface occurred. The diffusion processes lead to the formation of Kirkendall voids at the GaAs/CIGS interface. Transmission electron microscopy and nanoprobe energy dispersive spectroscopy were used to analyze the diffusion and void formation processes. The diffusivity of Ga in CIGS was found to be relatively low. This is postulated to be due to a comparatively low concentration of point defects in the epitaxial films. A reaction model explaining the observed profiles and voids is proposed.",

author = "Lei, {C. H.} and Rockett, {A. A.} and Robertson, {I. M.} and N. Papathanasiou and S. Siebentritt",

note = "Funding Information: This work was partly supported (HMI) by the German Research Ministry (BMBF) in the framework of “Hochspannungsnetz” and by the National Science Foundation under Award No. 0602938-0017756000 Materials World Network. The authors also gratefully acknowledge the support of the U.S. Department of Energy. At the beginning of the project the program “Fundamental studies of the defect chemistry of CIS” at UIUC was supported by the Office of Basic Energy Sciences under Contract No. DEFG02-91ER45439, which also supports the Center for Microanalysis of Materials at the University of Illinois. UIUC characterization of solar cell materials was also supported during the initial stage of this investigation through the National Renewable Energy Laboratory contract ADJ-2-30630-26.",

year = "2006",

doi = "10.1063/1.2397282",

language = "English (US)",

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journal = "Journal of Applied Physics",

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AU - Rockett, A. A.

AU - Robertson, I. M.

AU - Papathanasiou, N.

AU - Siebentritt, S.

N1 - Funding Information: This work was partly supported (HMI) by the German Research Ministry (BMBF) in the framework of “Hochspannungsnetz” and by the National Science Foundation under Award No. 0602938-0017756000 Materials World Network. The authors also gratefully acknowledge the support of the U.S. Department of Energy. At the beginning of the project the program “Fundamental studies of the defect chemistry of CIS” at UIUC was supported by the Office of Basic Energy Sciences under Contract No. DEFG02-91ER45439, which also supports the Center for Microanalysis of Materials at the University of Illinois. UIUC characterization of solar cell materials was also supported during the initial stage of this investigation through the National Renewable Energy Laboratory contract ADJ-2-30630-26.

PY - 2006

Y1 - 2006

N2 - Cu (In1-x Gax) Se2 (CIGS) films were grown on (001) GaAs at 570 or 500 °C by means of metal organic vapor-phase epitaxy. All films were Cu-rich [Cu (In+Ga) >1] with pseudomorphic Cu2 Se second phase particles found only on the growth surface. During growth, diffusion of Ga from the substrate and vacancies generated by the formation of CIGS from Cu2 Se at the surface occurred. The diffusion processes lead to the formation of Kirkendall voids at the GaAs/CIGS interface. Transmission electron microscopy and nanoprobe energy dispersive spectroscopy were used to analyze the diffusion and void formation processes. The diffusivity of Ga in CIGS was found to be relatively low. This is postulated to be due to a comparatively low concentration of point defects in the epitaxial films. A reaction model explaining the observed profiles and voids is proposed.

AB - Cu (In1-x Gax) Se2 (CIGS) films were grown on (001) GaAs at 570 or 500 °C by means of metal organic vapor-phase epitaxy. All films were Cu-rich [Cu (In+Ga) >1] with pseudomorphic Cu2 Se second phase particles found only on the growth surface. During growth, diffusion of Ga from the substrate and vacancies generated by the formation of CIGS from Cu2 Se at the surface occurred. The diffusion processes lead to the formation of Kirkendall voids at the GaAs/CIGS interface. Transmission electron microscopy and nanoprobe energy dispersive spectroscopy were used to analyze the diffusion and void formation processes. The diffusivity of Ga in CIGS was found to be relatively low. This is postulated to be due to a comparatively low concentration of point defects in the epitaxial films. A reaction model explaining the observed profiles and voids is proposed.

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