ILGAR technology. VIII. Sulfidic buffer layers for Cu(InGa)(S,Se)₂ solar cells prepared by ion layer gas reaction (ILGAR)

摘要

The ion layer gas reaction (ILGAR) is a novel deposition techniquefor chalcogenide compounds. This sequential and cyclic method, whichinvolves a solid-gas reaction, is used to deposit sulfidic buffer layerson Cu(InGa)(S,Se)₂ (CIGSSe) absorbers. Chemical pretreatmentsof the absorber in several metal salt baths are investigated, whichimprove the device performance of the solar cell significantly. In thecase of a Zn-bath a temperature above 100° C forces the modificationof the absorber surface resulting in a drastic increase of the opencircuit voltage with increasing bath temperature. As a first result thecombination of Cd-pretreatment and ILGAR-CdS buffer in a solar cell (0.5cm²) yields an efficiency of 14.2 % (total area) comparablewith the quality of the corresponding standard device (CBD-CdS buffer,η=14.1%); the Cd-free combination of Zn-pretreatment and ILGAR-ZnSbuffer also results in a device with an efficiency of 14.2 % (totalarea)