Copper content dependence of electrical properties and Raman spectra of Se-deficient Cu(In,Ga)Se2 thin films for solar cells
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- 作者：Lei Sun ; Jianhua Ma ; Niangjuan Yao…
- 刊名：Journal of Materials Science: Materials in Electronics
- 出版年：2016
- 出版时间：September 2016
- 年：2016
- 卷：27
- 期：9
- 页码：9124-9130
- 全文大小：1,303 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Optical and Electronic Materials
Characterization and Evaluation Materials - 出版者：Springer New York
- ISSN：1573-482X
- 卷排序：27
文摘
This paper reports the Raman spectra and electrical analysis of Se-deficient Cu(In,Ga)Se2 (CIGS) films with various Cu contents. These films were deposited by low-cost two-step process consisting of sputtering of metallic precursor and subsequent selenization. Raman spectra exhibit the formation of chalcopyrite phase while signs of secondary phases like CuxSe and ordered vacancy compound are also observed. Electrical measurements show the change of main carrier source as well as the transformation of conduction type with varying Cu content. Comprehensive analysis of Raman spectra and electrical measurements qualitatively explains the relationship between electrical properties and Cu contents. Based on this relationship, the optimal range of Cu/(Ga + In) for Se-deficient CIGS solar cells is identified as 0.875–0.925, which is smaller than that for Se-sufficient CIGS solar cells due to the presence of Se vacancies. The efficiency data of CIGS solar cells fabricated with same absorber deposition process are in good agreement with this optimal range. The results of this paper could be used to estimate device performance at early process stages.