Cu2ZnSnS4 (CZTS) thin films were deposited by sol-gel spin coating using precursor solutions prepared with copper acetate, zinc acetate, tin chloride, and thiourea in methanol and ethylenediamine followed by sulfurization. Sol-gel precursor solutions were prepared with different amounts of sulfur and copper, and their effects on film growth, crystal properties, and optical properties of CZTS films were investigated. CZTS film thickness increased with the amount of metal salt in the precursor solution. This is attributed to an increase in solution viscosity and a decrease in the solution density/viscosity ratio. All CZTS thin films exhibited kesterite structures with absorption coefficients larger than 104 cm-1 in the visible region. Band gap energy increased with increasing amounts of sulfur and decreasing amounts of copper. The blue shift of the band gap is attributed to changes in the degree of p-d hybridization related to Cu d- and S p-levels. The role of sulfur and copper on Hall mobility and carrier concentration was investigated. By optimizing the metal salt ratio in the precursor, CZTS film with a resistivity of 5.3 × 10-2 Ωcm were prepared.
|Number of pages||8|
|Journal||Journal of Materials Science: Materials in Electronics|
|Publication status||Published - 2013 Oct|
Bibliographical noteFunding Information:
Acknowledgments This work was supported by the New & Renewable Energy Technology Development Program of the Korea Institute of Energy, Technology, Evaluation, and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (20113020010010). The Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (2009-0093823) also supported this work.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering