Enhanced performance of γ-In₂Se₃ photodetector on ITO-coated interdigital electrodes fabricated via RF-magnetron sputtering

In this study, we investigated the effect of RF sputtering power on the structural, morphological, optical, and photodetector properties of γ-In₂Se₃ thin films. The In₂Se₃ films were deposited at 80 W, 100 W, 120 W, and 150 W and characterized using XRD, Raman spectroscopy, FE-SEM, and EDS. The XRD results showed that the rise in RF sputtering power enhanced the crystallinity of the prepared films. The formation of the γ phase of In₂Se₃ was confirmed by Raman spectroscopy. FE-SEM images showed that the In₂Se₃ films were compact, smooth, and had uniform grain growth. The increase in film thickness with RF power was observed in cross-sectional FE-SEM. The EDS analysis confirmed that as-prepared γ-In₂Se₃ films have stoichiometric chemical composition. The optical bandgap of the films decreased from 2.07 to 1.85 eV with an increase in RF power, which can be attributed to an increase in crystallite size due to an increase in RF power. The optoelectronic performance of the films was evaluated by fabricating γ-In₂Se₃ photodetectors. The photodetector fabricated at 100 W sputtering power had excellent performance. It had a detectivity of 2.5 × 10⁸ Jones, photoresponsivity of 17 µA/W, fast rise time of 0.27 s, and decay times of 0.31 s.