Electrochemical deposition of Na-doped p-type Cu2O film on n-type Si for photovoltaic application

• Electrochemical deposition of Na-doped Cu2O was successfully achieved.
• The incorporation of Na in Cu2O film enhances the resistivity and the hole concentration.
• The optimal Na content incorporated in Cu2O film was found to be ≈ 1.39 at.%.
• Cu2O/Si solar cell was fabricated based on undoped and Na-doped p-Cu2O films.

Sodium doped p-type Cu2O film deposited by electrochemical method was achieved by adding sodium alumina complex compound to the copper (II) lactic solution. The optimal incorporated Na content (measured in partial atomic percentage at. %) in Cu2O film was found to be approximately 1.39 at.%. As the Na content increased the resistivity dramatically decreased from (1.2 × 106 to 330) Ω·cm and the carrier concentration was also increased from (5.1 × 1014 to 1.7 × 1018) cm− 3.The XPS result shows the appearance of a binding energy at 1072.4 ± 0.2 eV corresponds to the presence of sodium related to sodium oxide. The Mott–Schottky plot confirms that the Cu2O film conductivity type was p-type and remains unchanged after the doping process. Cu2O/Si p-n heterojunction was fabricated using the undoped and the optimized Na-doped Cu2O film. The efficiency was improved from 0.05% to 0.45% or about nine times its value for the undoped.