CIGS Surface Research Articles

High resolution XPS studies of Se chemistry of a Cu(In, Ga)Se 2 surface

Chemistry of co-evaporated Cu(In, Ga)Se 2 (CIGS) surfaces submitted or not to chemical treatments was investigated by high resolution XPS. The surface analysis allowed us to compare the surface composition with the bulk one as a function of the treatments. We also studied too several standard compounds as Cu 2− x Se, In 2Se 3, ZnSe, Se 0 and CdSe. A Se XPS signal specific of the CIGS surfaces was identified. In this paper, we present a detailed study of Se signal in CIGS and show of the different spectroscopic contributions can be separated using standards information. Then, we discuss the chemical origin of these signals and the implications for the device processing.

Interface Defects in GIGS-based Solar Cells from Coupled Electrical and Chemical Points of View

ABSTRACTChemistry of co-evaporated CIGS surfaces submitted to chemical treatments relevant to fabrication steps were investigated by XPS and admittance spectroscopy. A Se XPS signal specific of the CIGS surfaces was identified. Surface states seen by Admittance and surface chemistry are seen to change significantly during the elaboration steps. Consequences for device elaboration are briefly discussed.

High-efficiency CIGS solar cells with modified CIGS surface

CIGS films were treated in In–S aqueous solution for high-efficiency CIGS solar cells. The In–S aqueous solution contained InCl 3 and CH 3CSNH 2 (thioacetamide). The In–S treatment modified the CIGS surface favorably for high-efficiency CIGS solar cells as evidenced by the increase in V oc, J sc and FF. The In–S treatment formed thin CuInS 2 layer on the CIGS surface which contributes to the high efficiency and stable performance of the CIGS solar cell. The best cell showed an efficiency of 17.6% ( V oc=0.649 V, J sc=36.1 mA/cm 2 and FF=75.1%) without any annealing and light soaking before I– V measurement.