A two-dimensional modeling of the fine-grained polycrystalline silicon thin-film solar cells

• Published in: Thin solid films 2002-02, Vol.403, p.258-262
• Main Authors: Christoffel, E, Rusu, M, Zerga, A, Bourdais, S, Noël, S, Slaoui, A
• Format: Article
• Language: English
• Subjects: 2D modeling; Grain boundary; Polycrystalline silicon; Solar cell; Thin film
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(01)01644-3

A two-dimensional device modeling for polycrystalline silicon thin-film solar cells was performed. A ThRee-dimensional Emitter Based on Locally Enhanced diffusion (TREBLE) concept was applied to evaluate the degree of leveling of the device efficiency. The model assumes a n +-p-p + junction device of a 3-μm grain size and 10-μm-thick polycrystalline Si columnar structure unit, where the n + regions extend along the grain boundaries. The analysis was carried out using ISE-DESSIS, a two-dimensional semiconductor device simulator. It has been found that open circuit voltage could be improved by increasing the base doping level to the optimum value of 10 17 cm −3. Preferential doping has a beneficial effect on short-circuit current of the cell and a slight influence on open circuit voltage. Conversion efficiency of ∼10% could be expected at the surface, recombination velocity of 10 4 cm/s and dopant diffusion depth along the grain boundary x gb=2.5 μm At base doping ∼10 17 cm −3 and well-passivated grain boundaries ( S gb=10 3 cm/s), an efficiency of approximately 12% may be obtained when x gb=3.7 μm.