+Three-step H2Se/Ar/H2S reaction of metal precursors for large area Cu(In,Ga)(Se,S)2 with uniform Ga distribution

A three-step H
2
Se/Ar/H
2
S reaction is used to process Cu-In-Ga metal precursors to form Cu(In,Ga)(Se,S)
2
films over 10 × 10 cm
²
substrates. The 1
^st
selenization step gives fine microstructure with Ga accumulation near the Mo back contact, primarily in a Cu
9
Ga
4
phase. Significant grain growth with homogenous through-film Ga distribution is obtained by the 2
^nd
Ar annealing step. The 3
^rd
sulfization step completes the reaction process and incorporates S near the Cu(In,Ga)Se
2
surface. The resulting films show good adhesion and yielded devices with η = 14.8% and V
OC
= 612 mV.