Locally resolved investigation of wedged Cu(In,Ga)Se 2 films prepared by physical vapor deposition using hard X-ray photoelectron and X-ray fluorescence spectroscopy
| Autor: | Britta Höpfner, Thomas Unold, Bünyamin Ümsür, Christan A. Kaufmann, Iver Lauermann, Martha Ch. Lux-Steiner, Karsten Prietzel, Wolfram Calvet |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Metals and Alloys X-ray Analytical chemistry Tantalum chemistry.chemical_element Surfaces and Interfaces Substrate (electronics) Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound X-ray photoelectron spectroscopy chemistry Molybdenum Physical vapor deposition Selenide Microscopy Materials Chemistry |
| Zdroj: | Thin Solid Films. 582:361-365 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/j.tsf.2014.11.067 |
| Popis: | We have investigated a specially grown Cu(In,Ga)Se2 (CIGSe) absorber, which was deposited by co-evaporation of Cu, In, Ga, and Se using a modified three stage process. Prior to the growth, the molybdenum-coated glass substrate was covered by a bent shroud made from tantalum (Ta), leading to a wedged absorber structure with a width of about 2 mm where the film thickness varies from 0 to 2 μm. In this region of interest the thickness dependency of morphology, concentration ratios and electronic properties was studied with secondary electron microscopy (SEM), X-ray fluorescence (XRF) and hard X-ray photoelectron spectroscopy (HAXPES), probing the CIGSe sample along the thickness gradient. The evidence of the thickness gradient itself was proven with SEM measurements in cross section geometry. By using XRF it was found that with decreasing film thickness the Cu concentration decreases significantly. This finding was also verified by HAXPES measurements. Furthermore, an enrichment of Ga towards the Mo back contact was found using the same technique. Besides these results the formation of a molybdenum selenide (MoSe) phase was observed on the fully covered part of the Mo coated substrate indicating a high mobility of Se on Mo under the given temperature conditions of the modified three stage deposition process. |
| Databáze: | OpenAIRE |
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