Transport properties of CuGaSe2-based thin-film solar cells as a function of absorber composition

THIN SOLID FILMS

卷:519

Article; Proceedings Paper

Rusu, M.¹  Baer, M.¹  Fuertes Marron, D.²  Lehmann, S.¹  Schedel-Niedrig, Th¹  Lux-Steiner, M. Ch¹ 

[1] Helmholtz Zentrum Berlin Mat & Energie GmbH, Solar Energy Res, D-14109 Berlin, Germany

[2] Escuela Tecn Super Ingenieros Telecomunicac, Inst Energia Solar, Madrid 28040, Spain

关键词: CuGaSe2;    Chalcopyrite;    Solar cells;    Transport mechanism;   

DOI  :  10.1016/j.tsf.2011.01.185

来源: Elsevier

【 摘 要 】

The transport properties of thin-film solar cells based on wide-gap CuGaSe2 absorbers have been investigated as a function of the bulk [Ga]/[Cu] ratio ranging from 1.01 to 1.33. We find that (i) the recombination processes in devices prepared from absorbers with a composition close to stoichiometry ([Ga]/[Cu] = 1.01) are strongly tunnelling assisted resulting in low recombination activation energies (E-a) of approx. 0.95 eV in the dark and 1.36 eV under illumination. (ii) With an increasing [Ga]/[Cu] ratio, the transport mechanism changes to be dominated by thermally activated Shockley-Read-Hall recombination with similar E-a values of approx. 1.52-1.57 eV for bulk [Ga]/[Cu] ratios of 1.12-1.33. The dominant recombination processes take place at the interface between CdS buffer and CuGaSe2 absorber independently from the absorber composition. The increase of E-a with the [Ga]/[Cu] ratio correlates with the open circuit voltage and explains the better performance of corresponding solar cells. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

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