A simple single elementary target sputtering method is proposed as an alternative to the multi-target sputter approach for preparing Cu2ZnSnSe4 absorber films. Several single targets utilizing excess Cu and Zn, including Cu2ZnSnSe4, Cu2Zn1.5SnSe4, Cu2.5Zn1.5SnSe4 and Cu3Zn1.5SnSe4, were investigated to determine the absorber film with the most promising structural and photovoltaic performance. A conversion efficiency of ~4.16% was obtained from the Cu2.5Zn1.5SnSe4 single target, which displayed well-defined grain structures with desirable Zn/Sn and Cu/(Zn+Sn) ratios. Critical roles of excess Cu and Zn during sputtering are discussed in conjunction with microstructural evolution, elemental distribution, photovoltaic characteristics and grain boundary contributions, which are specified for the sputtering method.
Bibliographical noteFunding Information:
This work was financially supported by a grant (no. 2011-0020285 ) from the National Research Foundation of Korea funded by the Korean government .
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films