Fabrication and characterization of indium tin oxide thin films used as a transparent conductive oxide layer in c-Si heterojection solar cells

The increasing global demand for clean energy has significantly boosted the use of renewable energy sources and highlighted the importance of photovoltaic (PV) technologies. Among these, crystalline silicon (c-Si) solar cells account for more than 90% of the PV market, leading to a focus on cost reduction and efficiency improvement in related research. In this context, silicon heterojunction (SHJ) solar cells have attracted significant attention due to their high-performance characteristics. This study aims to optimize indium tin oxide (ITO) thin films, used as a transparent conductive oxide (TCO) layer in SHJ cells. The characterization and optimization of ITO films were performed by varying the temperature, plasma power, and oxygen flow rate. ITO films with a thickness of 100 nm were deposited on glass substrates using physical vapor deposition (PVD) at different temperatures (RT, 150, 175, 200, 225, 250 °C), with the best results obtained at 200 °C. After temperature optimization, ITO films were produced at different plasma powers (1800, 1850, 1900, 1950, 2000, 2050 W), with optimum results at 2050 W. Additionally, oxygen flow rates (0, 1, 1.5, 2, 2.5, 3, 5 sccm) were tested, and 2.5 sccm was identified as the optimal value. The impact of this optimization on SHJ solar cell efficiency was analyzed, with a final efficiency of 21.64% measured.