CIGS solar cells grown by a three-stage process with different evaporation rates

• Published in: 2009 34th IEEE Photovoltaic Specialists Conference (PVSC) pp. 000812 - 000816
• Main Authors: Chirila, A., Guettler, D., Bremaud, D., Buecheler, S., Verma, R., Seyrling, S., Nishiwaki, S., Haenni, S., Bilger, G., Tiwari, A.N.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.06.2009
• Subjects: Coatings; Costs; Glass; Grain size; Laboratories; Photovoltaic cells; Polyimides; Scanning electron microscopy; Substrates; Temperature
• ISBN: 1424429498; 9781424429493
• ISSN: 0160-8371
• DOI: 10.1109/PVSC.2009.5411161

Solar cells based on polycrystalline Cu(In,Ga)Se 2 (CIGS) absorber layers have shown high potential for low cost photovoltaic energy conversion. Our group has achieved 18.1% efficient cells on glass substrates and 14.1% on flexible polyimide foils without antireflection (AR) coating. These results were achieved by applying a three-stage evaporation process with common growth rates of about 35 nm/min. Aim of this study was to enhance the growth rates of layers deposited at low substrate temperature (450°C) suitable for polyimide foils and to investigate structural properties of CIGS layers and photovoltaic properties of solar cells. It was found that very high deposition rates of 500 nm/min during the 2nd and 3rd stage of the evaporation process are feasible, maintaining high absorber quality and performance of solar cells.