Large-area cd-free CIGS solar modules with In2S3 buffer layer deposited by ALCVD

The development of Cd-free buffer layers by vacuum process for Cu(In,Ga)Se-2 (CIGS) solar modules becomes even more interesting regarding environmental aspects and the implementation in industrial production. This work presents the latest results of CIGS modules with indium sulfide (In2S3) as buffer layer deposited by the atomic layer chemical vapour deposition technique. A module efficiency close to 13% was realised on the area of 30 X 30 cm(2) (eta = 12.9%, V-OC = 27.8 V, FF = 72.6%, I-SC = 0.457 A, aperture area: 714 cm(2) and 42 cells). Diffusion processes at the buffer layer interfaces, dependent on deposition temperature and post annealing, have been investigated by X-ray photoelectron spectroscopy, secondary ion mass spectrometry and sputtered neutral mass spectrometry analysis. Diffusion of Cu and Na into the buffer layer and intermixing of S and Se at the In2S3/CIGS interface have been detected. (C) 2003 Elsevier B.V. All rights reserved.