In situ and ex situ characterisation of thermally induced crystallisation of CuInS2 thin films for solar cell

Ex situ structural characterization during the formation of CuInS2 thin films

“…The CA/(CA + CH) peak intensity ratios for the 500 and 500°C/15 min samples are 20.3% and 20.7%, respectively. This indicates that the sulfurization process reduces the amount of the undesirable CA structure to a level that is close to the lowest level reported [22]. Furthermore, the existence of the CA structure is also accompanied by the undesirable blue-shift and broadening of the CH peaks.…”

“…The CuIn 5 S 8 /(CH + CuIn 5 S 8 ) peak intensity ratios for the 310 and 400°C samples are 66.7% and 49.5%, respectively. On the other hand, the CuIn 5 S 8 /(CH + CuIn 5 S 8 ) peak intensity ratios for the 500 and 500°C/15 min samples reduce to 23.2% and 23.9%, respectively, due to the transformation of CuIn 5 S 8 into CIS [22]. Continuous sulfurization at 500°C leads to insignificant changes in the ratio.…”

“…1 and 2 show the existence of CIS structure. However, as noted above, it is known that CIS can exhibit two different structural orders: CH, which is stable at room temperature, and metastable CA [22]. In a single crystal, the Raman A1 mode of the CH structure is centered at 290 cm À1 [15].…”

Three dimensional web-like fibrous CuInS2 film

“…CIS-CuAu structure. Use of a copper-rich precursor has been suggested to increase the CH phase relative to the CA phase [26,27]. The peaks at 323, 337, and 349 cm −1 are the metastable CuIn 5 S 8 structure [28].…”

“…In general, Cu 2 S promotes crystal growth and decreases impurities while CIS is being formed. Cu 2 S plays the role of catalyst to transform CuIn 5 S 8 into CuInS 2 through the reaction: CuIn 5 S 8 + 2Cu 2 S → 5CuInS 2 [26,27,[29][30][31].…”