A comprehensive experimental investigation of La@CdS nanostructured thin films: Structural, opto-nonlinear and photodetection properties

Device grade La@CdS nanostructured thin films with hexagonal wurtzite structure were fabricated on glass substrates with 0 wt.%, 1.0 wt.%, 3.0 wt.% and 5.0 wt.% La doping concentrations by spray pyrolysis method. Comprehensive experimental investigations were systematically carried out on the prepared films. The obtained results revealed that the grown films demonstrate excellent opto-nonlinear and visible light photo-detection properties. The optical band gap values of the films were obtained using absorbance spectroscopy and were in the range 2.40–2.42 eV. On the other hand, the third order nonlinear optical susceptibility (χ(3)) values of the films were calculated and were found to be between 2.73 × 10−13–1.36 × 10−10 esu and were remarkably enhanced after La doping. The dark and photo currents were recorded as functions of La doping concentrations and the intensity of the light source as well. La@CdS based devices photodetection parameters like, responsivity, photosensitivity, external quantum efficiency and specific detectivity values were also obtained in the range of 0.101–1.02 A/W, 22–215, 22.97–241.0% and 8.98 × 1010–4.17 × 1011 Jones, respectively. The rise and decay times were also considerably improved after the incorporation of La in the CdS matrix.