Adhesion Dependence of the Electroplated Copper Electrodes on the Sputtering Condition of Transparent Conductive Indium Tin Oxide Layer for Silicon Heterojunction Solar Cells

Substituting copper for silver in electrodes is a promising approach to cut down the production costs of silicon heterojunction (SHJ) solar cells. Nevertheless, the adhesion between electroplated copper electrodes and transparent conductive oxide layers, like indium tin oxide (ITO) layers, is crucial for the reliable and stable operation of these solar cells. In this research, magnetron sputtering is utilized to fabricate ITO layers for the SHJ solar cells with electroplated copper electrodes and how the sputtering parameters influenced the performance of the solar cells, particularly the adhesion at the Cu/ITO interface, is explored. The results demonstrate that ITO layers deposited with high sputtering power density and low oxygen flow rate show high crystallinity and low oxygen content, which can contribute to the enhanced adhesion to the electroplated copper electrodes. Conversely, ITO layers made with low sputtering power density or high oxygen flow rate contain more oxygen and have a decreased corrosion resistance, which detrimentally affect the adhesion at the Cu/ITO interface. These findings provide an applicable way to fabricate the efficient and stable SHJ solar cells with electroplated copper electrodes by optimizing the ITO deposition.