Rapid thermal processing annealing challenges for large scale Cu sub(2)ZnSnS sub(4) thin films

• Published in: Physica status solidi. A, Applications and materials science Vol. 212; no. 1; pp. 103 - 108
• Main Authors: Vauche, Laura, Dubois, Jerome, Laparre, Aurelie, Pasquinelli, Marcel, Bodnar, Sylvie, Grand, Pierre-Philippe, Jaime, Salvador
• Format: Journal Article
• Language: English
• Published: 01-01-2015
• Subjects: Annealing; Conversion; CZT; Stress concentration; Sulfides; Synthesis; Thin films; Volatility
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201431387

Electrodeposition followed by rapid thermal annealing is a favorable process for industrial solar thin film fabrication. In this regard, we attempt to develop a process for earth-abundant pure sulfide kesterite solar cells fabrication of Cu sub(2)ZnSnS sub(4) (CZTS) at pre-industrial scale (1515cm super(2)). Synthesis at a large scale is a challenging issue that we attempt to address discussing the choice of annealing parameters. We found out that in our system a low background pressure is needed to ensure a good vapors distribution. However, S, SnS, Zn volatilities are enhanced, making difficult the control of the composition. Annealing temperature profile has a strong influence on the final absorber composition. The introduction of an intermediate reactive pre-alloying step previously to the high temperature annealing is shown to help to obtain more compact absorbers, leading to a maximum power conversion efficiency of 2.4% for a 0.435cm super(2) CZTS device.