Role of tellurium addition on the linear and non‐linear optical, structural, morphological properties of Ag_60‐xSe₄₀Te_x thin films for nonlinear applications

Abstract

The tellurium (Te)-doped Ag 60-x Se 40 Te x (x = 0%, 5%, 10%, 15%) thin films of thickness ∼800 nm were prepared from the bulk sample by thermal evaporation method on a glass substrate. The X-ray diffraction study revealed the amorphous nature of the films whereas the change in vibrational modes was noticed from the Raman spectroscopy. The composition of the films was verified by energy dispersive X-ray analysis and the surface morphology pictures were taken by field emission scanning electron microscopy and atomic force microscope. The changes in optical properties (linear and non-linear) with Te addition were studied from UV-Visible spectroscopy data and related empirical formulas. The addition of Te reduced the bandgap values significantly and the reduction in transmission resulted in the increase of the linear refractive index. The decrease in optical bandgap is due to an increase in disorder while the width of the tail in the gap increased with Te%. The optical density, dispersion energy, extinction coefficient, carrier concentration, dielectric constant, oscillator wavelength increased while the oscillator energy, oscillator strength, optical electronegativity decreased with Te content. The electrical susceptibility increased with Te content. The non-linear susceptibilities and the non-linear refractive index increased which is good for the nonlinear photonic devices.

Study of the characterizationn of CdTe thin films prepared by the pulsed laser deposition technique with different laser energies

“…The extinction coefficient (K ) of the analysed films is an important parameter that provides information about the interaction of incoming light with the material through the material's capacity for absorption. Formula (3) expresses the extinction of the electromagnetic wave in the material [35].…”

Annealing-induced phase transformation in In10Se70Te20 thin films and its structural, optical and morphological changes for optoelectronic applications

“…68 In other way, according to the chemical bond approach, the formation of greater bond energy-based bonds such as In-Se (53.64 kcal mol −1 ), Se-Te (44.18 kcal mol −1 ) and In-Te (33.05 kcal mol −1 ) occurs at rst, followed by low energy-based bonds Te-Te (33 kcal mol −1 ) and Se-Se (44 kcal mol −1 ). 49,69,70 The local structure in the lm changed by bond breaking and bond arrangement due to annealing the thin lms. Therefore, the low-energy bonds along with some dangling bonds were annealed with the formation of stronger bonds In-Se and In-Te bonds.…”

Synthesis and Optical Properties of Potassium‐Based Wide‐Bandgap Mixed–Halide Perovskite KPbF2Cl Nanorods

“…To determine the bandgap (E g ) of the system, a Tauc plot (Figure 7) is made by using αhγ = A(hγ À E g ) n , where α is the absorption coefficient, h is the Planck's constant, γ is the frequency of the incident photons, A is an energyindependent proportionality constant, and the exponent n denotes the type of electronic transition between the conduction and valence bands, such as n = 1/2, 2, 3, and 3/2 for direct allowed, indirect allowed, indirect forbidden, and direct forbidden transition, respectively. [38][39][40][41] Since an indirect bandgap is found in KPbF 2 Cl from our calculations, here n = 2 is considered for the Tauc plot (see inset of Figure 7). The intercept of the line along the slope on the hγ axis represents E g with (αhγ) 1/2 equal to zero, providing a bandgap of 4.04 eV.…”