Effect of Different Annealing Techniques on CIGS Deposited Using One-Step Single-Target Sputtering

The post-processing of CuInGaSe 2 (CIGS) thin films deposited using a single-target sputtering method was studied. Post-processing annealing was performed in a traditional muffle furnace and rapid thermal processing (RTP) tube furnace. The samples were annealed at 450°C for 10 min in a muffle furnace and subsequently quenched, whereas multiple quenching cycles were performed in RTP. The structural, optical, elemental, and morphological properties of the samples were analyzed. The obtained XRD data were refined using the Rietveld refinement algorithm, which showed that the c/a value approaches the ideal tetragonal crystal structure in the RTP-treated sample and that the crystallinity of the RTP-treated sample was better than that of the traditional furnace-annealed samples. Optical measurements showed increased absorbance values in the RTP-treated samples compared with the furnace-annealed samples. Bandgap was estimated to be 1.30 eV, 1.22 eV, and 1.18 eV for as-deposited, furnace annealing, and RTP-treated samples. Our experiment showed that better results were obtained in the RTP-treated samples, with a similar parameter used for annealing.