Fabrication of ᵞ-In₂Se₃-Based Photodetector Using RF Magnetron Sputtering and Investigations of Its Temperature-Dependent Properties

Metal chalcogenide indium selenide (In2Se3) is attracting increasing research interest for photodetector applications due to its excellent photoresponse and superior stability under ambient conditions. However, the temperature-dependent performance of In2Se3-based photodetectors has rarely been reported. Here, $\gamma $ -In2Se3 thin films were prepared at various deposition pressures using the RF magnetron sputtering for photodetector applications. The formation of single-phase $\gamma $ -In2Se3 films has been confirmed by the X-ray diffraction (XRD) and Raman analyses. Binding energies and elemental composition of $\gamma $ -In2Se3 films were examined by XPS analysis. Field emission scanning electron microscopy (FE-SEM) images show that the prepared $\gamma $ -In2Se3 films were crack- and pore-free, dense, compact, smooth, and have small grains. The optical energy bandgap decreases from 2.2 to 1.7 eV with an increase in deposition pressure. Then, the photoresponse of $\gamma $ -In2Se3-based photodetectors was investigated. The photodetector fabricated with $\gamma $ -In2Se3 at 5 Pa on an ITO-coated interdigital electrode (IDE) exhibited excellent photoresponsivity ( $2.82~\mu \text{A}$ /W) and detectivity ( $7.06\times 10^{{7}}$ Jones) with a fast rise time of 0.26 s and a decay time of 0.32 s. Finally, the temperature-dependent photoresponse of the photodetector fabricated with $\gamma $ -In2Se3 at 5 Pa is meticulously investigated. We found that the photodetector properties of a photodetector critically depend on the operating temperature.