Influence of the GA Content on the Mo/Cu(In,Ga)Se2 Interface Formation

Culn
_1-x
Ga
_x
Se
₂
(CIGS) thin films with various Ga contents x were characterized by micro-Raman spectroscopy. All samples were investigated using the 532 nm line of a Nd:YAG laser in the back-scattering geometry. A linear increase of the frequency of the chalcopyrite A
₁
mode from 174 cm
^-1
to 184 cm
^-1
with increasing Ga content was observed. Special attention was directed to the interface between the CIGS absorber and the Mo back contact. Sputtered neutral mass spectroscopy (SNMS) and Raman line scans on cross-sections revealed a reduced formation of MoSe
₂
at the Mo/CIGS interface for higher Ga contents