Residual strain measurement of Cu₂ZnSnS₄ thin film using X-ray line broadening

ABSTRACT

In this study, the residual strain in Cu₂ZnSnS₄ (CZTS) photoabsorber for solar cell application was analyzed by X-ray line broadening. Metal precursor of CZTS was deposited on a glass substrate using the co-sputtering method with Cu, Zn, and Sn single targets at a substrate temperature of 100°C. Then, the metal precursor was sulfurized within a previously evacuated corning tube that at the present stage contained sulfur powder at an annealing temperature of 550°C for 10 min. The structural properties of a CZTS thin film were analyzed by performing X-ray diffraction. The main peaks, (112), (220), and (312) were clearly visible. The residual strain was determined by using a Williamson–Hall (W–H) plot, which is a very convenient tool for determining the residual strain of thin films. The slope of the graph indicates the residual strain of the CZTS thin film, and it is determined as 2.831 × 10^{− 4}. Using the W–H plot, it was concluded that the residual stress of CZTS thin film is tensile.

KEYWORDS:

• CZTS
• residual strain
• residual stress
• solar cell
• Williamson-Hall plot

Additional information

Funding

This study was supported by the Daegu University Research Grant, 2017.