Commercially available metal substrates such as ferritic Cr steel and titanium have been smoothed by:
- Electrochemical polishing (INASMET)
- Mechanical polishing (INASMET)
- The deposition of a levelling SiOx layer (CIEMAT).
Mirror like surfaces were obtained by a mechanical polishing procedure. The differently treated foils have been analysed and assessed by fabrication of CIGS devices (IPE, ZSW) and application of different measurements (SEM, AFM, profilometry, optical microscopy, SIMS, I/V-curve).
Various dielectric (e.g. SiOx) and conductive (e.g. Cr) layers were deposited and evaluated as diffusion barriers against the diffusion of detrimental elements from the steel substrate into the CIGS absorber. A specific selective CIGS pollution procedure has been successfully applied at the IPE to identify detrimental elements. A chemical treatment of the CIGS absorber was applied to remove residual contaminants accumulating at the CIGS surface.