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Określenie poziomu domieszkowania w absorberach ogniw słonecznych Cu(In,Ga)Se2

Ćwil M.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 5

65-66

PL

Przedstawiono badania rozkładu domieszkowania w absorberach ogniw słonecznych Cu(ln,Ga)Se2 przy wykorzystaniu metody pojemnościowo-napięciowej (C-V). Profil rozkładu defektów w warstwie aktywnej uzyskany na podstawie charakterystyki C-V jest silnie niejednorodny za co odpowiedzialny jest elektrostatyczny ładunek zgromadzony w głębokich stanach materiału. Koncentracja głębokich pułapek jest ok. rząd wielkości większa aniżeli poziom domieszkowania płytkich stanów akceptorowych. Dyskusja i wnioski wsparte są numerycznymi symulacjami charakterystyk C-V przy użyciu programu SCAPS.

EN

Capacitance-voltage profiling has been used in order to determine net shallow acceptor concentration in the absorber of Cu(ln,Ga)Se2 - based solar cell. The influence of deep defects on evaluation of spatial doping distribution in the bulk of Cu(ln,Ga)Se2 absorber is discussed. We attribute the apparent non-uniformity of doping profile towards the back electrode to the accumulation of electrostatic charge in deep bulk acceptors with concentration an order of magnitude higher than net shallow doping. All conclusions have been tested by SCAPS numerical modeling.

2

Electron traps in Cu(In,Ga)Se2 absorbers of thin film solar cells studied by junction capacitance techniques

Igalson M., Zabierowski P.

Opto-Electronics Review

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2003

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Vol. 11, No. 4

261-267

EN

The results of steady state and transient capacitance spectrocsopy for ZnO/CdS/Cu(In,Ga)Se2 solar cells are presented. A minority carrier signal from the interface region of absorber has been investigated using Laplace-DLTS. Contributions belonging to three discrete electron traps with thermal emission rates distorted by electric field - assisted tunnelling have been identified and assigned to InCu antisite defect. Support for these conclusions has been also provided by admittance spectroscopy of samples in various metastable states created by prolonged exposition to light, voltage bias or elevated temperature. Two other deep electron traps have been revealed by the use of DLTS injection. One of them, tentatively assigned to the VSe defect, is involved in the metastable phenomena observed in Cu(In,Ga)Se2 - based solar cells. Judging from the high value of capture cross section for carriers of both signs we conclude that it might be a dominating recombination centre in these devices.

3

Reverse-bias DLTS for investigation of the interface region in thin film solar cells

Igalson M., Zabierowski P., Romeo A., Stolt L.

Opto-Electronics Review

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2000

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Vol. 8, No. 4

346-349

EN

The interface states in TCO/Cds/CdTe and ZnO/CdS/Cu(In,Ga)Se₂ photovoltaic devices has been studied by use of reverse-bias transient capacitance spectroscopy. Laplace transform analysis has been used in order to enhance a spectral resolution of the technique. It is shown that the method yields useful information on the electronic characteristics of the heterointerface in the thin film solar cells. The conclusion include a degree of inversion of the heterointerface and a contribution of tunneling in the carrier transport. The influence of these factors on photovoltaic performance of the devices under study is discussed.