Microcrystalline silicon solar cells with passivated interfaces for high open-circuit voltage

• Published in: Physica status solidi. A, Applications and materials science Vol. 212; no. 4; pp. 840 - 845
• Main Authors: Hänni, Simon, Boccard, Mathieu, Bugnon, Grégory, Despeisse, Matthieu, Schüttauf, Jan-Willem, Haug, Franz-Josef, Meillaud, Fanny, Ballif, Christophe
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.04.2015; Wiley Subscription Services, Inc
• Subjects: Crystal structure; Devices; Electric potential; interfaces; microcrystalline silicon; open-circuit voltage; passivation; Photovoltaic cells; Silicon; Solar cells; Thin films; Voltage
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201431708

We introduce passivating hetero‐interfaces in single‐junction microcrystalline silicon (μc‐Si:H) solar cells. We investigate the effect of different i–n layer stacks in thin μc‐Si:H devices, in which recombination is significant at the interfaces as well as in the bulk material. By applying amorphous silicon passivating layers at the μc‐Si:H i–n interface, we show a device with a high open‐circuit voltage (Voc) of 608 mV, for a standard Raman crystalline fraction of the i‐layer (>50%). This Voc is the highest reported value for a state‐of‐the‐art μc‐Si:H device made by plasma‐enhanced chemical vapor deposition. We also report an efficiency of 9.45% for a solar cell with an absorber layer as thin as 650 nm on an area greater than 1 cm2, and show with a simple crystalline silicon model that for such thin μc‐Si:H devices or μc‐Si:H devices with a very high bulk‐material quality, well‐mastered interfaces and doped layers are of paramount importance for high efficiency.