Soft chemical growth of Zn0.8Mg0.2S one dimensional nanorod thin films for efficient visible light photosensor

Herein, we report the synthesis of well-aligned Zn0.8Mg0.2S one-dimensional (1-D) nanorod thin films for visible-light photosensor application. Zn0.8Mg0.2S 1-D nanorod thin films were synthesized by a simple one-step chemical bath deposition technique on a glass substrate for the first time. The as-grown thin film with a thickness of ∼250 nm had an average crystallite size of ∼19 nm and the optical band gap of 3.32 eV. The enhancement in bandgap to 3.56 eV of the as-grown thin film was observed when annealed at 100 °C for 1 h. The X-ray diffraction (XRD) patterns obtained from as-grown and annealed thin films confirms the formation of mixed phase crystal geometry and decrease in average crystallite size after annealing. The obtained Raman spectra exhibit the Raman peaks originating from ZnS/O and MgS/O phonons. The photosensing properties of Zn0.8Mg0.2S thin films showed an excellent photoresponsivity of 0.89 μA/Watt and 1.523 μA/Watt for as-grown and annealed thin films respectively. The 90.51% photosensitivity with the response and recovery time of ∼93 s and ∼140 s respectively was obtained for the annealed thin film under illumination of 100 W/cm2 at a bias voltage 5 V. In conclusion, the high photosensitivity for visible light proves its potential use as a visible-light photosensor.