MOCVD indium sulphide for application as a buffer layer in CIGS solar cells

Indium sulphide has a high potential as a buffer layer material in Cu(In,Ga)Se2 (CIGS) solar devices. In this work a metal organic vapour deposition (MOCVD) process was investigated for the indium sulphide deposition. Trimethyl-indium and t-butyl-thiol were applied as precursor sources. The films produced with different process conditions were characterised by scanning electron microscopy. We also present the first results of CIGS laboratory cells with an MOCVD indium sulphide buffer layer. The best device showed an efficiency of 12.3% (CdS reference = 13.0%) at a deposition temperature of 300 °C and a deposition time of 20 min, combined with a 5 min post-annealing treatment at 200 °C in air.