https://doi.org/10.1051/epjpv/2013022
Investigation of silicon heterojunction solar cells by photoluminescence under DC-bias
1
Total Énergies Nouvelles, La Défense, France
2
LPICM, CNRS – École Polytechnique, Palaiseau, France
3
Energy Research Unit, Indian Association for the Cultivation of
Science, Kolkata,
India
4
Inorganic and Physical Chemistry Research Division,
Institut Teknologi
Bandung, Indonesia
a
e-mail: guillaume.courtois@polytechnique.edu
Received:
30
July
2012
Accepted:
4
June
2013
Published online:
27
September
2013
Photoluminescence measurements on solar cells are usually carried out under open-circuit conditions. We report here on an innovative approach, in which the samples are simultaneously illuminated and DC-biased, so that the luminescence can be monitored under several operating points, that is to say several injection levels, ranging from short-circuit conditions to the light-emitting regime of the device. The experiments were performed on in-house made c-Si/a-Si:H heterojunction solar cells illuminated by a continuous green laser diode and positively biased. The luminescence spectra obtained this way were compared to those obtained with no light excitation source, which corresponds to usual electroluminescence mode and dark J(V). Firstly, the obtained luminescence spectra have shown the expected exponential dependence on the applied voltage. Furthermore, given that the amplitude of the emitted luminescence is proportional to the radiative recombination rate, this approach enables to indirectly characterise the non-radiative recombination phenomena. In the case of HJ solar cells with intrinsic thin layers processed on high quality FZ-wafers, non-radiative recombination is dominated by the defects at the c-Si/a-Si:H interface. The luminescence measurements presented here therefore give information on the quality of the surface passivation. An estimation of the interface defect density was achieved by comparing our experimental results with modelling.
© Courtois et al., published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative
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