DocumentCode :
3197799
Title :
Effects of Impurities in CdTe/CdS Structures: Towards Enhanced Device Efficiencies
Author :
Halliday, D.P. ; Emziane, M. ; Durose, K. ; Bosio, A. ; Romeo, N.
Author_Institution :
Dept. of Phys., Durham Univ.
Volume :
1
fYear :
2006
fDate :
38838
Firstpage :
408
Lastpage :
411
Abstract :
We report on a comprehensive study of the effect of impurities in thin film CdTe/CdS PV structures. Dynamic, quantitative SIMS and ICPMS spectrometry have been used to analyze starting materials, device layers and final device structures. Source materials of different purity were used: CdCl2 (5N to 95%), CdTe (7N to 5N), CdS (4N) and TCO (5N). Structures grown on glass have been compared with those grown on sapphire. Impurity profiles were obtained for O, Na, Si, Cl, Cu, Zn, Sn, Sb, In, Pb, S, Cd and Te. The profiles for Cu, Zn, Sn and Pb were found to be independent of the CdTe starting material and post-growth CdCl2 treatment. Cl, O, Na and Si had higher levels in structures grown with 5N CdTe source material. Interdiffusion of Te and S was enhanced in devices grown with 5N CdTe. In was found to originate from the TCO. Na originated principally from the glass but was also introduced by the use of lower grade CdCl2. The Si profile was independent of the substrate used. Intentional incorporation of 62 during the CdTe growth led to an enhanced concentration of both O and Cl in finished devices. This resulted in an improvement in all device parameters and an increase in efficiency from 11.5% to 14%
Keywords :
II-VI semiconductors; cadmium compounds; chemical interdiffusion; impurities; mass spectroscopic chemical analysis; secondary ion mass spectra; semiconductor growth; semiconductor thin films; solar cells; 11.5 to 14 percent; Cd; CdCl2; CdS; CdTe; CdTe growth; CdTe source material; CdTe-CdS; Cl; Cu; ICPMS spectrometry; In; Na; O; Pb; S; Sb; Si; Si profile; Sn; TCO; Te; Zn; device layers; device structures; enhanced device efficiencies; glass; impurity effects; impurity profiles; interdiffusion; post-growth treatment; quantitative SIMS; sapphire; thin film PV structures; Cascading style sheets; Glass; Impurities; Physics; Plasma temperature; Sputtering; Substrates; Tin; Transistors; Zinc;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
1-4244-0017-1
Electronic_ISBN :
1-4244-0017-1
Type :
conf
DOI :
10.1109/WCPEC.2006.279476
Filename :
4059649
Link To Document :
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