Accurate CIGS composition measurements using surface analytical techniques

Conversion efficiency for Cu(In
_x
, Ga
_1-x
)Se
₂
is dependent on a number of factors including band-gap and defect structures. Material composition affects band gap and it affects the formation of defect structures. A fundamental understanding of the relationship between material composition, band gap and defect structures requires that the composition measurement be accurate. Accuracy is required for really explaining how and why the cells function. Why certain defect levels form as a function of concentration, and how the influence of defects is mitigated by compensation from other defects, also dependent on the composition. [1] In this work we will look at the accuracy of a number of analytical techniques. We evaluate strengths and limitations of each for reporting useful information on thin film CIGS materials and evaluate them for accuracy in reporting CIGS composition.