CIGS layers were grown using NaF and LiF precursor layers with different th
icknesses deposited on top of the Mo back contact layer prior to the CIGS d
eposition. The substrates were soda lime glass with and without Na diffusio
n barriers. Two types of barriers were used, silica and alumina. The CIGS l
ayers were analysed structurally with SEM, TEM and XRD, and solar cell devi
ces were prepared. We found improvements in grain structure, film texture a
nd surface flatness when NaF precursor layers were used as compared to Na-f
ree and Na-poor samples. Also electrically we found that the solar cell eff
iciency increased with modest additions of Na. Changes in film morphology s
aturated at an NaF thickness of 30 Angstrom and the solar cell efficiency s
aturated with an NaF precursor thickness of about 100 Angstrom. NaF precurs
or layers were also used at lower deposition temperatures and we observed i
mproved solar cell efficiencies using the NaF precursor layer, even at subs
trate temperatures as low as 310 degrees C. (C) 2000 Published by Elsevier
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