XPS characterization of different thermal treatments in the ITO–Si interface of a carbonate-textured monocrystalline silicon solar cell

In this work we have applied the X-ray photoelectron spectroscopy (XPS) in depth to study, for the first time, the influence of different thermal treatments in the ITO–Si interface of a monocrystalline Si-based solar cell where the Si surface is carbonate-textured and covered by an ITO sputtered layer. The efficiency of the solar cells significantly increases when thermal treatments are applied just after the ITO deposition. The efficiency is also dependent on the characteristics of the pyramidal relief of the silicon surface previously obtained by immersion of the Si wafers in a sodium carbonate/bicarbonate solution. An efficiency of 15.5% has been obtained with an optimized texturization of the silicon substrates and an annealing treatment of the solar cells at 400 °C just after the ITO deposition.