A study of CIS thin films prepared by SEL technique
| Autor: | Chun-Hong Chiu, 邱俊閎 |
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| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 I-III-VI2 solar cells such as CuInSe2 (CIS) compound semiconductor is a great candidate for large-area solar panels because of its high efficiency, reliable long-term performance and potential for low-cost production. The high absorption coefficient (~105 cm -1) can be obtained from a thin CIS layer. A 2 μm CIS film is sufficient to absorb the most useful part of the solar spectrum. The most widely accepted methods are co-evaporation of the elements on heated substrate and annealing of Cu-In precursors in H2Se or Se atmosphere. Both processes are extremely toxic to health and harmful to environment. In my thesis, a new approach to form CIS absorber film is presented. Ternary semiconductor CIS thin films prepared by stack element layer (SEL) technique (i.e. In/Se/Cu, etc.) using sputtering for Cu/In and chemical bath deposition (CBD) technique for Se followed by a one-step selenization. The advantages of using CBD Se process is that it is a low-cost process and pollution free, i.e. it totally avoided usage of highly toxic H2Se or Se vapor. The studies of growth CBD Se versus deposition time have been carried out. Thick enough CBD Se film and proper Cu/In thickness can fabricate 2 μm thick CIS film. Different stacking sequences to form CIS absorber were studied by comparing the reaction mechanisms. In/Se/Cu is the best stacking structure for preparing CIS absorber films. Using this structure, we have achieved a close 1:1:2 stoichiometicy ratio for Cu, In and Se,respectively. Thin film has a high XRD intensity on the CIS (112) plane. The total thickness of the CIS film was about 2μm and had grain sizes of 2 - 2.5 μm. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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