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Zn(O,OH) layers in chalcopyrite thin-film solar cells: Valence-band maximum versus composition.
- Source :
- Journal of Applied Physics; 9/1/2005, Vol. 98 Issue 5, p053702, 8p, 1 Chart, 4 Graphs
- Publication Year :
- 2005
-
Abstract
- Zn(O,OH) layers deposited by the ion layer gas reaction (ILGAR) technique have the potential to replace the conventionally used CdS buffer layer in Cu(In<subscript>(1-X)</subscript>Ga<subscript>X</subscript>)(S<subscript>Y</subscript>Se<subscript>(1-Y)</subscript>)<subscript>2</subscript>-based thin-film solar cells. To avoid stability issues, the fraction of metastable Zn(OH)<subscript>2</subscript> should be reduced in the final buffer layer. However, hydroxide-poor or -free ZnO “buffers” result in noncompetitive devices. We have therefore investigated the impact of different oxide/hydroxide ratios on the electronic band alignment at the absorber/buffer heterointerface. The surface composition as well as the position of the valence-band maximum (VBM) of respective ILGAR-Zn(O,OH) samples was determined by photoelectron spectroscopy. The position of the conduction-band minimum (CBM) was estimated using optical band gaps determined from optical reflection/transmission measurements. From the comparison of these VBM and CBM values with the respective values of the absorber surface, predictions are made in terms of valence- and conduction-band offsets at the crucial absorber/buffer interface. The results are compared with previous findings, and the drawn conclusions are correlated with the performance of respective solar cell devices. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 98
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 18332745
- Full Text :
- https://doi.org/10.1063/1.2034650