Photoelectric characteristic of single-phase In_xGa_1-xN films with tunable bandgap through RF magnetron sputtering

In_xGa_1-xN films with tunable bandgap hold significant potential for photoelectric applications, particularly in wavelength-selective and UV–visible photodetection. Herein, a unique target was designed to prepare bandgap-tunable In_xGa_1-xN films by RF (radio frequency) magnetron sputtering. By adjusting the RF power to change the In content (x value), we prepared In_xGa_1-xN films with bandgap variations in the range of 2.15–2.63 eV. Upon further investigation, it was found that the grown In_xGa_1-xN films had hexagonal structure and did not undergo phase separation in the In-rich composition. With the increase of In content from 0.46 to 0.60, the preferred orientation of the In_xGa_1-xN films changed from (101) to (100) plane, while the surface morphology of the In_xGa_1-xN films changed from worm-like to spherical grains. Photoluminescence peaks of In_xGa_1-xN films was composed of intrinsic and defect luminescence. Under irradiation of 450 and 650 nm laser, the responsivity of the In_xGa_1-xN metal–semiconductor-metal photodetector can reach 5.15 × 10⁻⁷ and 3.2 × 10⁻⁷ A/W, and the fastest response time can reach 1.28 and 1.32 s, respectively.