Investigation on structural and photodetection properties of Gd2O3 thin films after annealing

In the present study, the electron beam evaporation technique was employed to deposit gadolinium oxide thin films (Gd₂O₃-TF) on the silicon substrate. The as-grown sample was then annealed at different annealing temperatures with a cooling/heating ramp of 5 °C/min. The successful growth of thin films and formation of the polycrystalline nature with cubic crystal system were confirmed using field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mean crystallite size was found to increase from ~ 8.64 to ~ 12.51 nm after post-deposition annealing at 500 °C. The electrical analysis was evaluated by preparing a device using Ag contact on the as-grown and the 500 °C annealed Gd₂O₃-TF. The annealed device showed an enhanced responsivity of 1.83 A/W with an internal gain of 9.08. The detectivity recorded for the as-grown and annealed devices was 2.23 × 10¹³ Jones and 4.31 × 10¹³ Jones, whereas values for noise equivalent power (NEP) were 2.52 × 10^–13 and 1.30 × 10^–13 W, respectively. Also, a fast switching response was observed with a rise/fall time value of 0.34 s/0.15 s upon annealing, which makes the device suitable for photodetector application.