Abstract
The optical transmittance of cells with Cu-Doped CdS thin films (CdS (Cu) films) was studied to investigate the electromigration of Cu in the CdS films. Cells with SnO2/CdS (Cu) /Au structure were fabricated by successive deposition of Cu (30 nm) and CdS (500 nm) on the SnO2 (F) film at 200°C, and deposition of semitransparent Au film at room temperature. Cu atoms diffused thermally into CdS films. The transmittance of the cells changed upon appling dc voltage to the cells. The change of transmittance of the cells was remained after a high electric field (about 106V/m) was removed from the cells. When the bias was positive for the SnO2 electrode relative to the Au electrode, the transmittance increased. However, the transmittance decreased when the bias was negative for the SnO2 electrode. These characteristics suggest that Cu+ ions migrate to the negative electrode in CdS films under high electric field at room temperature.
