Physical, linear and nonlinear optical properties of amorphous Se90-xTe10Mx (M = Zn, In, Pb, x = 0, 5) chalcogenide thin films by electron-beam deposition

Ganesan

et al. 2022

ACS Appl. Opt. Mater.

This study investigates the effects of 30 keV proton ion irradiation on the structural, morphological, and linear–nonlinear optoelectronic properties of Sb40Se20S40 thin films. The retention of an amorphous nature and vibrational bonding rearrangements caused by ion irradiation demonstrate structural tailoring. The cumulative decrease in roughness with an increase in ion dose decreases the surface energy and optical absorption loss. With the blue shifting of the absorption edges, proton irradiation increased the optical transmittance and reflectance. The variation of fluence changes the optical bandgap and Urbach energy, which are induced by local structural changes caused by defects and disorder. The refractive index decreased considerably, which supports the Moss rule. Proton irradiation reduced the interband transition and average band energy gap of the system. However, ion irradiation increased optical losses while decreasing optical conductivity and dielectric characteristics. The third-order nonlinear susceptibility and nonlinear refractive index decreased significantly as the fluence increased. Such materials with optical tuning capabilities via ion fluence are essential for cutting-edge photonic and optoelectronic applications.

Section: Resultsmentioning

confidence: 99%

Section: Refractive Index (N) Dispersionmentioning

confidence: 99%

Influence of Proton Ion Irradiation on the Linear–Nonlinear Optoelectronic Properties of Sb₄₀Se₂₀S₄₀ Thin Films at Different Fluences for Photonic Devices

Priyadarshini¹,

Ganesan

et al. 2022

ACS Appl. Opt. Mater.

“…The chalcogenide glasses have large nonlinearity than the usual silica (∼1000 times more than silica) due to the presence of a large number of polarizable ions or atoms . All the nonlinear parameters, that is, linear optical susceptibility χ (1) , third-order nonlinear optical susceptibility χ (3) , and second-order nonlinear refractive index n 2 , are linked to the dielectric polarization due to the electric field applied to the thin films . The first-order nonlinear optical susceptibility χ (1) can be expressed in terms of linear refractive index by the given relation .…”

Section: Resultsmentioning

confidence: 99%

“…65 All the nonlinear parameters, that is, linear optical susceptibility χ (1) , third-order nonlinear optical susceptibility χ (3) , and second-order nonlinear refractive index n 2 , are linked to the dielectric polarization due to the electric field applied to the thin films. 66 The first-order nonlinear optical susceptibility χ (1) can be expressed in terms of linear refractive index by the given relation 60 (3) given by The obtained χ (1) and χ (3) values are presented in Table 1, which vary in a similar manner to that of the other linear parameters. The variation of nonlinear susceptibility (3) with E g for the different films is shown in Figure 5d, which finds a window-type change with ion fluence.…”

mentioning

confidence: 99%

Proton Ion Irradiation on As₄₀Se₅₀Sb₁₀ Thin Films: Fluence-Dependent Tuning of Linear–Nonlinear Optical Properties for Photonic Applications

Sahoo¹,

Sahoo

ACS Appl. Electron. Mater.

et al. 2022

The present work is focused on the impact of proton irradiation (30 keV) on the structural, optical, and morphological properties of thermally evaporated As 40 Se 50 Sb 10 thin films. The fluence-induced linear and nonlinear optical parameters were calculated from the transmittance, reflectance, and absorbance data obtained from UV−vis spectroscopy in the range of 550−1100 nm. The increase in transmittance suggests that the material is getting more transparent upon proton irradiation. The change in absorption edge, optical band gap, and refractive index represents the post-irradiation effect. The disorder in the film influenced the density of defect states in the localized state region, which led to the changes in the optical band gap. The variation of dispersion and dielectric parameters such as dispersion energy, oscillator energy, dielectric constant, plasma frequency, and real and imaginary optical conductivities upon proton irradiation displays the tuning capabilities of As 40 Se 50 Sb 10 . The higher values of nonlinear optical parameters with proton irradiation are essential for cutting-edge photonic applications. The X-ray diffraction reveals the amorphous nature of the films after proton irradiation, and the microstructural changes were noticed from the Raman spectra. 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 microscopy.

“…For chalcogenide materials, nonlinearity is one of the important properties that covers a broad portion of the electromagnetic spectrum. Therefore, it has wide application in the field of optical switching, optical computing and electro-optics, infrared sensing, planar waveguides, etc. − The nonlinear properties of the materials are determined by the polarization effect of the material when electromagnetic radiation propagates through it. When an electric field is applied to the material, an induced polarization occurs inside it.…”

Section: Resultsmentioning

confidence: 99%

Thermal Annealing-Induced Transformation of Structural, Morphological, Linear, and Nonlinear Optical Parameters of Quaternary As₂₀Ag₁₀Te₁₀Se₆₀ Thin Films for Optical Applications

Das¹,

Senapati²,

et al. 2022

ACS Appl. Opt. Mater.

This work focuses on the structural, optical, and morphological modifications in As 20 Ag 10 Te 10 Se 60 quaternary thin films that are ∼800 nm thick upon thermal annealing at different temperatures. The structure is analyzed by Xray diffraction that reveals the phase transformation (amorphous to crystalline) due to annealing. This material's phase transition enables it to be used in memory device applications. The increase in particle size is confirmed by field emission scanning electron microscopy of the surface. The increase in particle size signifies the agglomeration occurs at higher annealing temperatures. The optical transmittance shows a red shift toward a lower photon energy as recorded by the ultraviolet−visible spectrometer. The optical bandgap of the films decreases (1.84 to 1.72 eV), whereas the refractive index increases as calculated from the Swanepoel method. The decrease in the bandgap is attributed to the increases in the localized states. The amorphous to crystalline transition results in a significant increase in the third-order nonlinear susceptibility (from 4.524 × 10 −11 to 14.146 × 10 −11 esu). The nonlinear refractive index is found to increase from 5.385 × 10 −10 to 14.786 × 10 −10 esu upon annealing. The static and high-frequency dielectric constant increases with the increase in oscillator and dispersion energy. The observed changes are explained on the basis of phase transformation and the density of defect states. The enhanced value of the nonlinear refractive index with a reduced optical electronegativity and carrier concentration with annealing is useful for nonlinear optical devices.