SEMINAIRE LMGP - 30.03.2021 - Abderrahime SEKKAT

Abderrahime SEKKAT
Ph.D. student,
Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, 38000 Grenoble, France
Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP, IMEP-LaHC, 38000 Grenoble, France
Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMAP, 38000 Grenoble, France

   Cuprous oxide (Cu₂O) is a non-toxic and abundant p-type semiconductor with a direct band gap around 2.1 eV and a large visible absorption coefficient. It has been studied and developed for several devices such as solar cells, thin film transistors or batteries. However, controlling the defect formation, transport properties, and the phase material seem to be a challenging task especially when using soft chemistry and low-cost approaches. Here, an innovative technique for depositing conformal and high-quality thin films, AP-SALD (Atmospheric Pressure Spatial Atomic Layer Deposition), is used to deposit Cu₂O at low temperatures (below 260 °C), under atmospheric pressure for photovoltaic applications. AP-SALD is an alternative approach to conventional ALD in which the precursors are separated in space rather than in time, allowing fast deposition rates as compared to conventional ALD (up to nm/s in some cases). I will show that using this technique, the Cu₂O thin films can be tuned in terms of defect formation and transport properties. By optimizing the deposition conditions and the precursor used, record conductivity and mobility values have been achieved. The Cu₂O thin films have been integrated in all-oxide solar cell as an absorber film and to silicon heterojunction solar cells as a hole transport layer. The results performances obtained have been correlated with simulation studies. Finally, we have also achieved a full control over the different phase of the material, namely, cuprous and cupric oxide and its metallic phase.