Interface-Barrier-Induced J-V Distortion of CIGS Cells With Sputtered-Deposited Zn(S,O) Window Layers

Sputtered-deposited Zn(S,O) is an attractive alternative to CdS for the window layer of Cu(In,Ga)Se 2 (CIGS) thin-film solar cells due to its higher band gap, which allows greater blue-photon collection. However, distortions to current-voltage ( J-V) curves are observed in some cases. A straightforw...

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Bibliographic Details
Published inIEEE journal of photovoltaics Vol. 4; no. 3; pp. 942 - 947
Main Authors Tao Song, McGoffin, J. Tyler, Sites, James R.
Format Journal Article
LanguageEnglish
Published Piscataway IEEE 01.05.2014
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects
Charge carrier density
Charge carrier processes
Cu(In
current-voltage (J-V) distortion
Ga)Se _{2} (CIGS
Lighting
Photoconductivity
Photonics
Photovoltaic cells
Solar energy
sputtering
Temperature measurement
thin films
Zn(S
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Summary:Sputtered-deposited Zn(S,O) is an attractive alternative to CdS for the window layer of Cu(In,Ga)Se 2 (CIGS) thin-film solar cells due to its higher band gap, which allows greater blue-photon collection. However, distortions to current-voltage ( J-V) curves are observed in some cases. A straightforward photodiode model with a secondary barrier at the Zn(S,O)/CIGS interface is employed to explain the physical mechanisms of the experimental J-V distortions. The primary contributor to the secondary barrier is the conduction-band offset (CBO), whose magnitude is determined by the oxygen fraction in Zn(S,O) and by the carrier density of Zn(S,O); the latter may be increased with indium-doping. Comparison of experimental and simulated J-V characteristics with variation in oxygen fraction, window carrier density, and temperature, allows a reasonably compelling test of the secondary-barrier model for this system.
ISSN:2156-3381
2156-3403
DOI:10.1109/JPHOTOV.2014.2301894