Direct Copper Plating to IWO for Silicon Heterojunction Solar Cells

Indium tungsten oxide (IWO) can provide advantages over indium tin oxide (ITO) as a transparent conducting oxide silicon heterojunction (SHJ) solar cells due to its lower absorption in the long wavelength region. However, low-temperature metallization methods are required for IWO-coated cells. This paper introduces a new process for the direct Cu plating to IWO surfaces for SHJ cells. The process, which employs a rapidly-plated initial seed Cu layer, can achieve strong interfacial adhesion and specific resistivity values as low as 1.81 ± 0.32 mΩ-cm
²
. It is proposed that the enhanced contact adhesion resulted from the reduced Cu nuclei grain size at the IWO-Cu interface and increased surface roughness.