Extraction of the Surface Recombination Velocity and Diffusion Length from LBIC and EBIC Measurements at Grain Boundaries in mc Silicon

Autor: Zuschlag, A., Micard, G., Junge, J., Kaes, M., Seren, S., Hahn, G., Coletti, G., Jia, G., Seifert, W.
Jazyk: angličtina
Rok vydání: 2008
Předmět:
ISSN: 1915-1918
Popis: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1915-1918
The surface recombination velocity at grain boundaries as well as the intra-grain diffusion length can be extracted in principle from Light and Electron Beam Induced Current measurements (LBIC and EBIC). This paper focuses on the influence of the grain size and the impact of hydrogen passivation steps during the solar cell process on these parameters. A set of differently treated multicrystalline floatzone (mc FZ) solar cells with different grain sizes (0.2–1 mm) was characterized by LBIC and EBIC measurements. Efficiencies reached on the processed solar cells (up to 16.0%) are the highest reported so far for material with such small grains. Also, the positive effect of hydrogenation can clearly be seen and quantitatively compared by extraction of the surface recombination velocity and the intra-grain diffusion length using a direct fitting procedure. Compared to [1] the describing theoretical model is adapted and extended [2], which allows the modeling of neighboring grains with different diffusion length. The obtained results could be very helpful for evaluation and determination of the efficiency potential of small grained wafer materials.
Databáze: OpenAIRE