Study of Cd-free buffer layers using Inx(OH,S)y on CIGS solar cells

The alternative buffer layer material Inx(OH,S)y was deposited on Cu(In,Ga)Se2 (CIGS) thin films by chemical-bath-deposition (CBD). The impurities in Inx(OH,S)y buffer layers and their atomic concentration were characterized by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) analyses. In addition, AES was used to depth profile the samples. The band-gap energy of the deposited Inx(OH,S)y was determined from optical absorption data. Both the dark- and photo-current-voltage (I–V) characteristics of the CIGS solar cells with Inx(OH,S)y buffer layers were measured, and the results were compared to the CIGS cells deposited with CBD CdS buffer layers.