CuInS 2 (CIS) absorber thin films were prepared by sulfurization of In/Cu metallic stacked precursor. The precursor thin films were sulfurized using a commercial furnace system in the S 2 (s) + Ar atmosphere at 425°C for 1 h. Effects of different S vapor temperature from 150 to 400°C on the structural, morphological, compositional and optical properties of CIS thin films were investigated. X-ray diffraction and Raman studies showed that the sulfurized thin films with S vaporization temperature below 300°C exhibited CIS tetragonal structure with secondary phases such as Cu x S y , CuIn 5 S 8 , and In x S y . The sulfurized thin films with S vaporization temperature over 350°C showed a single CIS tetragonal structure. Compositional ratio of CIS thin films showed that Cu/In and S/(Cu + In) ratio in the CIS thin films with S vaporization temperature over 350°C were 1.0-1.2 and 0.9-1.1, respectively, while compositional ratio deviated from stoichiometry when the sulfurized thin films below S vaporization temperature of 350°C. Optical study showed that the band gap energy and the absorption coefficient of CIS thin films were estimated from 1.18 eV to 1.5 eV and over 10 4 cm -1 , respectively.
Bibliographical noteFunding Information:
This work is supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.: 20124010203180) and partially supported by a grant from the Fundamental R & D program for Core Technology of Materials funded by the Ministry of Knowledge Economy (10037233).
- Low cost process
- S powder
- Thin film solar cells (TFSCs)
- Vaporization temperature