Transparent Conductive Oxide in Silicon Heterojunction Solar Cells

摘要

Devices and methods for reducing optical losses in transparent conductive oxides (TCOs) used in silicon heterojunction (SHJ) solar cells while enhancing series resistance are disclosed herein. In particular, the methods include reducing the thickness of TCO layers by about 200% to 300% and depositing hydrogenated dielectric layers on top to form double layers of antireflection coating. It has been discovered that the conductivity of a thin TCO layer can be increased through a hydrogen treatment supplied from the capping dielectric during the post deposition annealing. The optimized cells with ITO/SiO_x:H stacks achieved more than 41 mA/cm² generation current on 120-micron-thick wafers while having approximately 100 Ohm/square sheet resistance. Further, solar cells and methods may include integration of ITO/SiO_x:H stacks with Cu plating and use ITO/SiN_x/SiO_x triple layer antireflection coatings. The experimental data details the improved optics and resistance in cell stacks with varying materials and thicknesses.