Materials for Optical Sensors of X-ray Irradiation Based on (Ga_xIn₁ – _x)₂Se₃ Films

(Ga_𝑥In_1−𝑥)₂Se₃ films with 0.1≤𝑥≤0.4 were deposited by the thermal evaporation technique. As-deposited (Ga_𝑥In_1−𝑥)₂Se₃ films were irradiated using the wideband radiation of a Cu-anode X-ray tube at different exposure times. The spectral dependences of the refractive index and extinction coefficient are measured by the spectral ellipsometry technique. The optical transmission spectra of X-ray irradiated (Ga_𝑥In_1−𝑥)-2Se₃ films are studied for various irradiation times. Parameters of the Urbach absorption edge for X-ray-irradiated (Ga_𝑥In_1−𝑥)₂Se₃ thin films are determined and compared with those of non-irradiated films. The spectral dependences of the refractive indices of non-irradiated and X-ray-irradiated (Ga_𝑥In_1−𝑥)₂Se₃ films are described in the framework of the model developed by Cauchy, Sellmeier, Wemple, and DiDomenico, as well as by the optical-refractometric relation. The detailed variation of the parameters of the Wemple–DiDomenico model for non-irradiated and X-ray-irradiated(Ga_𝑥In_1−𝑥)₂Se₃ films has been analyzed. The perspective of applications of (Ga_𝑥In_1−𝑥)₂Se₃ films as the materials for optical sensors of X-rays is discussed. (author)