Effects of thermal stressing on CdTe/CdS solar cells

Author

Tetali, B. ; Viswanathan, V. ; Morel, D.L. ; Ferekides, C.S.

Author_Institution

Center for Clean Energy & Vehicles, Univ. of South Florida, Tampa, FL, USA

fYear

2002

fDate

19-24 May 2002

Firstpage

600

Lastpage

603

Abstract

The effects of thermal stressing on CdTe/CdS thin film solar cells have been investigated. Cadmium telluride solar cells fabricated by close-spaced sublimation, and contacted with Cu-based back contacts have been subjected to temperatures ranging from 70 to 120°C in inert ambient for over 3500 hours. The average starting V_oc and ff for all stressed devices were 840 mV and 72% respectively. The devices were periodically removed from the stress environment and their light and dark J-V characteristics were measured. It has been found that all cells exhibited some degree of degradation, which was accelerated with temperature. Changes in device characteristics appeared to be gradual for temperatures in the range of 70-90°C. In all cases a significant portion of the observed degradation took place within the first 500-600 hours. SIMS analysis indicated that the stress process resulted in Cu-accumulation near the CdTe/CdS junction, suggesting that Cu is at least partially responsible for the observed junction degradation.

Keywords

II-VI semiconductors; cadmium compounds; copper; dark conductivity; doping profiles; photoconductivity; secondary ion mass spectra; semiconductor device measurement; solar cells; thermal stresses; 3500 hour; 500 to 600 hour; 70 to 120 degC; 840 mV; CdTe-CdS; CdTe/CdS solar cells; Cu; Cu-based back contacts; J-V characteristics; SIMS analysis; close-spaced sublimation; degradation; device characteristics; thermal stressing; Copper; Degradation; Glass; Manufacturing; Ovens; Photovoltaic cells; Stress measurement; Temperature distribution; Thermal stresses; Transistors;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE

ISSN

1060-8371

Print_ISBN

0-7803-7471-1

Type

conf

DOI

10.1109/PVSC.2002.1190636

Filename

1190636