Graduation Year


Document Type




Degree Granting Department

Electrical Engineering

Major Professor

Christos S. Ferekides, Ph.D.

Committee Member

Don L. Morel, Ph.D.

Committee Member

Yun L. Chiou, Ph.D.


Copper, Transients, Degradation, Stress testing, Light soaking


Solar energy is one of the abundant, non-polluting renewable energy options in our planet. During the last three decades considerable progress has been achieved in developing technologies to produce electricity from solar radiation, but producing electricity with low cost and low pollution is of concern. The CdTe solar cells are the leading source for the production of cost effective solar cells. The main issue of concern in these CdTe solar cells is degradation observed when stressed at elevated temperatures. The degradation in CdTe solar cells can be attributed to the back contact, which often contains Cu to improve the electronic properties of CdTe (absorber layer) and to enable a quasi ohmic back contact.

The main objective of this thesis was to study effect of amount of Cu in the back contact and contact annealing temperature on device stability. The samples used for this study had varied amounts of Cu sputtered thickness in the back contact and varied contact annealing temperatures. The stress tests were conducted in dark and light, at elevated temperatures, and under open circuit and short circuit conditions. The stress analysis was done after 700 hours of light soaking. Degradation in specific parameters like Voc, FF, Rse, Rsh has been noted and an attempt has been made to explain these results.