Lauwaert, Johan

Van Puyvelde, Lisanne

Vanhellemont, Jan

Vrielinck, Henk

English

Ghent University Academic Bibliography

Assignment of anomalous DLTS signals to additional barriers in Cu(In,Ga)Se2 solar cellsJ. Lauwaert, L. Van Puyvelde, J. Vanhellemont and H. VrielinckDepartment  of  Solid  State  Sciences,  Ghent  University,  Krijgslaan  281-S1, 9000 Gent, BelgiumKeywords: CIGS, DLTS, Solar cellsCIGS thin-film solar  cells  are multiple-layer structures.   DLTS is traditionally applied for studying carrier trapping by defects. Spectra recorded  on  thin-film  devices  are  often  interpreted  in  terms  of defects  in  the  absorber  layer or  at  its  interfaces.  Recently,  in the context  of  interpretation  of  the  capacitance  spectroscopy  signals observed for CIGS solar cells, we studied the DLTS characteristics  of a non-Ohmic contact in layered structures - acting as a junction  polarized oppositely to the main junction - theoretically, on model devices and on actual solar cells. We found that such a contact may give rise to a strong DLTS signal that can readily be distinguished from that  of defects by comparing DLTS results  after regular and inverted electric pulses [1].  We also demonstrated that the signal of  defects  located  either  in  a  certain  layer  or  at  interfaces  between layers cannot exhibit these properties [2].  It was shown that both the N1 and the N2 signals  reported  in  literature  for  CIGS solar  cells exhibit the behavior of contacts, rather than of defects in the layers [3]. The DLTS signals of  non-ideal  contacts  may be very intense and hamper the intended detection of carrier trap levels inside the layer.  Nonetheless, they may also provide valuable information on the thin-film device if they allow to extract the diode characteristics of the non-ideal contact. In this work we demonstrate that, via fitting the DLTS spectra with regular and inverted pulses of various heights, one can determine these parameters.  [1] Lauwaert et al.  J. Appl. Phys 109, 063721 (2011)[2] Lauwaert et al.  Progress In Photovoltaics 20(5), 588-594 (2012)[3] Lauwaert et al.  Sol. Ener. Mater. Sol. Cells 112, 78-83 (2013)

Assignment of anomalous DLTS signals to additional barriers in Cu(In,Ga)Se2 solar cells

https://biblio.ugent.be/publication/4100828/file/4100865.pdf

Assignment of anomalous DLTS signals to additional barriers in Cu(In,Ga)Se2 solar cells

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Ghent University Academic Bibliography