In-situ investigation of Cu-In-Se reactions by thin film calorimetry

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:323659

Wolf, D; Mueller, G ^[1]

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1. Univ. of Erlangen-Nuernberg, Erlangen (Germany). Crystal Growth Lab.

Studies of the reaction path during annealing of Cu-In-Se thin films for solar cell absorbers have been limited up to now to ex-situ analyses of the phase composition by X-Ray Diffraction (XRD) after processing by a specific temperature-time program. As an indirect method, the application of ex-situ XRD /is not sufficient for the determination of reaction temperatures and reaction times for setting up a general model of CIS-formation. The authors show in this paper that the use of a calorimetric method (Thin film Calorimetry, TFC) offers the advantage of a direct (in-situ) observation of thin film reactions. Special care is taken to use film thicknesses of practical interest for industrial application (1.5--3 {micro}m). In a first step the authors show results of binary reactions in the Cu-In, In-Se and Cu-Se systems. Their knowledge is necessary for understanding the processes involved in the ternary CIS-layers. It turned out that thin Cu-In and Cu-Se films react already at room temperature and behave as predicted by the bulk equilibrium phase diagrams during heating. In-Se thin films show prominent exothermic reactions starting with the melting of In. The first phase to be formed is generally In{sub 2}Se which is then converted to more Se-rich compounds. In ternary Cu-In-Se films (Cu/In = 1.00) the authors observe transitions of the Cu-Se-system which can be attributed to the decomposition of CuSe{sub 2} and CuSe. Consequences for the model of improved CIS-growth by a Cu-Se flux agent are discussed.

• OSTI ID: 323659
• Report Number(s): CONF-971201--
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
ANNEALING
CHEMICAL REACTIONS
COPPER SELENIDE SOLAR CELLS
COPPER SELENIDES
FABRICATION
INDIUM SELENIDE SOLAR CELLS
INDIUM SELENIDES
PHASE STUDIES