Influence of sputtered gallium oxide as buffer or high-resistive layer on performance of Cu(In,Ga)Se2-based solar cells

• Published in: Journal of materials research Vol. 37; no. 11; pp. 1825 - 1834
• Main Authors: Witte, Wolfram, Hempel, Wolfram, Paetel, Stefan, Menner, Richard, Hariskos, Dimitrios
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 14.06.2022; Springer Nature B.V
• Subjects: Ammonia; Antireflection coatings; Applied and Technical Physics; Biomaterials; Buffers; Cadmium sulfide; Chemistry and Materials Science; Copper indium gallium selenides; Deposition; Gallium oxides; Inorganic Chemistry; Invited Paper; Magnetron sputtering; Materials Engineering; Materials research; Materials Science; Nanotechnology; Photovoltaic cells; Solar cells; Substitutes; Thin films; Zinc oxide; Thin films; Solar cells; Cu(In,Ga)Se; Wide bandgap; Sputtering; Gallium oxide
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/s43578-022-00608-z

Oxides could be candidates for buffer, passivation, or high-resistive (HR) layers in Cu(In,Ga)Se 2 (CIGS) thin-film solar cells. From an industrial point of view, a high-rate and dry deposition method like sputtering would be the most favorable technique. This study presents results with the wide-bandgap material gallium oxide (Ga 2 O 3 ) deposited by magnetron sputtering applied as a substitution for the traditional CdS buffer or the intrinsic ZnO (i-ZnO) HR layer. With state-of-the-art CIGS absorber layers, subject to a RbF post-deposition treatment, an ammonia rinsing of the CIGS surface before sputtering of X-ray amorphous Ga 2 O 3 has mostly a positive impact on device performance reaching efficiencies up to 14%. An efficiency of 20.2% with anti-reflective coating was achieved with Ga 2 O 3 applied as HR layer as substitution for i-ZnO in combination with a solution-grown CdS buffer and ZnO:Al as front contact. This result is comparable to the efficiency of 20.4% for the CIGS/CdS/i-ZnO/ZnO:Al reference cell. Graphical abstract