Characterization of the interface properties in a-Si:H/c-Si heterostructures by photoluminescence

S Tardon (1) , R Brüggemann (1)

1 Institut für Physik

Photoluminescence measurements on hydrogenated amorphous silicon / crystalline silicon (a-Si:H / c-Si) heterostructures have been used for two aspects of their characterisation: the monitoring of the crystalline silicon wafers and of their interface properties after different steps of solar cell processing and the tracking of interface properties on purpose-built symmetrical structures with different amorphous silicon overlayers. The difference in the quasi-Fermi level splittings in these symmetrical structures, determined both experimentally and by numerical modelling, suggest an energetic position of the interface defect distribution with a peak at around 0.7 eV – 0.8 eV above the c-Si valence band edge. Numerical modelling is also applied to the structures after solar-cell processing steps and consistently tracks the variation in quasi-Fermi level splitting, i.e., excess carrier densities, in the c-Si layer. The agreement in the experimental and simulated open-circuit voltages for the final cell adds confidence to the interface defect parameters determined.

Mots clés: photoluminescence; recombination; a-Si:H/c-Si; heterostructure; solar cell

S Tardon, R Brüggemann. Characterization of the interface properties in a-Si:H/c-Si heterostructures by photoluminescence. Journal of Physics D: Applied Physics, 2010, 43 (11), pp.115102. ⟨10.1088/0022-3727/43/11/115102⟩. ⟨hal-00569553⟩