A review on metal-doped chalcogenide films and their effect on various optoelectronic properties for different applications

Abstract

Chalcogenide thin films have been investigated and explored in the last several decades to widen their use in optical, electronic, and optoelectronic device sectors. The phenomenon corresponding to different induced stimuli effects, doping foreign elements is the most productive and efficient way to improve their structural ability, optical characteristics, and electronic approaches. Based on that, metal doping has an enormous impact on the aspects and understanding of the mechanism inside the matrix. This review is mainly based on metal-doped chalcogenide thin films, their effect on various properties of the host materials, and several applications based on that. Thin films doped primarily with bismuth (Bi), antimony (Sb), silver (Ag), tin (Sn), and copper (Cu) were analyzed and discussed. Progress in understanding their structure, bonding, and properties within the matrix was also discussed. This paper also describes the importance and developments of these metal-doped thin films, their physicochemical aspects, and their applications in optoelectronic devices. Different potential applications of these metal-doped chalcogenide thin films in manufacturing technology-based optoelectronic devices, namely sensors, waveguides, switching devices, batteries, optical memories, etc., are also highlighted.

Fig. 1. (a) The transmittance (b) absorption coefficient (α) (c) (αhν)^1/2vs. hν (eV) variation for Ge₃₀Se_70−xBi_x film, (d) the change in transmittance (e) absorption coefficient, and extinction coefficient (inset plot) (f) optical bandgap of As₄₀Se_60−xBi_x thin films.

Fig. 2. (a) The transmittance spectra dependence behavior over wavelength and (b) (αhν)^1/2vs. hν (eV) variation for Bi/As₂S₃ films. (c) The transmission change and (d) bandgap variation for Bi/GeSe₂ film, (e) the transmittance and (f) refractive index spectral behavior over wavelength and energy of Bi/In₂Se₃ thin films.

Fig. 3. (a) The transmittance and (b) optical bandgap variation in as-prepared and irradiated Sn/As₂Se₃ thin films. The Sb doping variation in (c) transmittance behavior and (d) optical energy gap of As_2−xS_3−xSb_x thin film, respectively. The compositional variation for Sb doped As₄₀Se_60−xSb_x thin film in (e) transmittance and (f) optical energy gap behavior. (g) The transmittance and (h) optical energy gap behavior for Sb_xS₄₀Se_60−x thin films with different dopant concentrations.

Fig. 4. (a) Transmittance and reflectance spectra of Ag/GeS as-prepared and illuminated thin films, (b) refractive index dispersion behavior of the Ag/GeS thin films, (c) variation of E_g and χ⁽³⁾ with bilayer Ag/GeS film, (d) transmittance spectra (e) refractive index variation and (f) band energy with nonlinear susceptibility of Ag/Se bilayer thin films.

Fig. 5. (a) Plot of (αhν)²vs. energy (hν) for the undoped and Sn doped CdSe thin films which showed a decreased pattern with different doping percentage, (b) plot of log(resistivity) with the inverse of absolute temperature for the undoped and Sn doped CdSe thin films, (c) photoluminescence emission spectra of undoped and Sn doped CdSe thin films at room temperature showing the variation in the intensity concerning doping percentage.

Fig. 6. (a) Optical transmission (T) of GeSe_2−xSn_x films (0 ≤ x ≤ 0.8) as a function of wavelength of light λ, (b) variation of refractive index (n) against wavelength (c) (αhν)^1/2versus hν for GeSe_2−xSn_x films.

Fig. 7. (a) Transmittance spectra (b) plots of (αhν)²versus hν and (c) variation of refractive index Cu doped SnS thin films prepared at various doping concentrations. (d) Transmittance spectra of pure and Cu doped SnS thin films prepared by sol–gel method, (e) plots of (αhν)²versus hν of pure and Cu doped SnS thin films.