Depth profile measurements

Description

X-ray photoemission and absorption spectroscopies (XPS/HAXPES, XAS/GI-XAS) offer non-destructive depth profile analysis of layered samples. They could be used for example to explore composition profile, secondary phase formation, local atomic structure, chemical and electronic properties in thin film solar cells.

In a previous study we employed HAXPES to study the chemical and electronic
properties at the interface between a CdS buffer and (Ag,Cu)(In,Ga)Se2 absorbers that have been exposed to different alkali metal fluoride treatments (RbF or CsF), which are known to improve the performance of the solar cells. The results gave insights into how selective alkali post deposition treatments could change the absorber surface composition, which is likely to influence the solar cell behavior.

The Cu and Ga decrease and Ag increase was found to be stronger for the RbF treatment as compared to CsF, and this could be correlated to observed device characteristics. You may find the full publication here

In a related study, GI-XAS was employed to study the local atomic-scale structure in
ACIGS absorbers with in depth composition variations. The results showed that local atomic arrangement of the ACIGS is depth-dependent and deviates from expectations of the long-range crystallographic structure. You may find the full publication here