A comparative study of heat-light soaking effect on CIGS thin film solar cells with zinc compound buffer layers deposited by ALD and CBD processes

摘要

The effects of a heat-light-soaking (HLS) on the cell performance were investigated for Cu(In,Ga)Se2(CIGS) thin-film solar cells with CBD-ZnS(O,OH) and ALD-Zn(O,S) buffer layers. The CBD-ZnS(O,OH)/CIGS andALD-ZnS(O,S)/CIGS solar cells respectively showed a drastic increase and a slight increase in all basic cell parametersafter the HLS post-treatment under AM1.5, 100mW/cm2 illumination at 130 °C. X-ray photoelectron spectroscopyshowed the decreased S/(S+O) atomic ratio of the CBD-ZnS(O,OH) buffer layer, implying re-arrangement of theconduction-band offset at the CBD-ZnS(O,OH)/CIGS interface. On the other hand, the change in S/(S+O) atomic ratio ofALD-Zn(O,S) buffer layer was not observed. By optimizing the HLS and the deposition conditions for each layers, CBDZnS(O,OH)/CIGS and ALD-Zn(O,S)/CIGS solar cells yielded total efficiencies of 18.8 and 18.7%, respectively.