Effect of iodine content on optical properties of chalcohalide glasses Ix(As20Se80)100-x

doi:10.1016/j.jnoncrysol.2020.120261

Journal of Non-Crystalline Solids

Volume 546, 15 October 2020, 120261

https://doi.org/10.1016/j.jnoncrysol.2020.120261 Get rights and content

Highlights

•
Preparation of chalcohalides with different content in Iodine.
•
Measurements of linear and nonlinear properties on evaporated thin films.
•
Effect of iodine content on the optical properties is pointed out.
•
Comparison of the measured band gap with theoretical prediction.

Abstract

The effect of iodine content in I_x (As₂₀Se₈₀)_100-x where x=0, 4, 8, 12, and 16 atomic % was studied both theoretically and experimentally. The calculated mean coordination number, cohesion energy, mean overall bonding energy, and band gap decrease with iodine content. This is correlated to the decrease of crosslinking by progressive incorporation of iodine. The impact of increasing iodine content on optical properties was studied through the analysis of a single reflection spectrum using Minkov's method. The experimentally evaluated band gap decreases from 1.7 eV to 1.41 eV in good agreement with the different estimations based on Manca's relation. The Urbach energy, related to the structural disorder, increases with the incorporation of iodine. From the measured refraction index, one deduces that the single oscillator energy decreases with iodine content while its dispersion energy increases. The nonlinear optical properties increase substantially with the incorporation of the more polarizable iodine atom.

Introduction

There is an increasing interest of combining chalcogenide and halide glasses in order to use their individual characteristics and overcome their shortcomings [1], [2], [3], [4], [5], [6]. From one side, chalcogenide glasses (ChGs) have good transparency in the mid - near infrared region and good chemical stability making them essential materials for infrared devices [7]. From other side, halide glasses (HGs) are also good infrared optical materials [8] and are known for their low optical loss but have less chemical stability, low glass transition temperature and high crystallizing ability compared to their ChG counterpart. Consequently, chalcohalides should have both good IR transmissions extended to the mid-infrared range as well as good chemical stability and enhanced glass forming ability. In general, chalcohalide shows enhanced infrared optical properties and good chemical stability. Furthermore, the structure becomes less cross-linked and shows a better capability of dissolving rare-earth ions which makes these glasses good candidate for active devices as fiber amplifiers or micro lasers [6,9,10].

The binary chalcogenide system As_xSe_1-x is known for its wide applications and large photosensitivity resulting in the ability of photo-induced surface gratings or structural changes [11], [12], [13]. Hence many investigations aimed to correlate its structural and physical properties [14], [15], [16]. Particularly, the composition dependence of As_xSe_1-x shows a clear maximum [14] at the coordination 2.4 as proposed by the rigidity model based on percolation proposed by Philipps and Thorpe [17].

Iodine (I) has a low melting temperature (113.7°C) and large atomic radius (133 pm), hence its addition to chalcogenides has interested many authors [2,3,18] and was found to enhance the packing density and improves the glass formation ability by preventing crystallization. Furthermore, iodine could broaden the transmission window by shifting upward the mid-infrared cutoff. Consequently, the introduction of iodine is expected to lower the absorption in the atmospheric IR windows making these compounds interesting for solar cells. The increasing optical application of chalcohalide is urging scientists to study the effect of incorporating halide within chalcogenide glasses on the optical properties mainly the index of refraction n and the extinction coefficient k. In order to study thermally evaporated thin glassy films, the commonly used experimental methods to deduce n and k of a glassy thin film is by analyzing either the single transmission spectrum [19], or both transmission and reflection spectra [20]. In addition to these methods, we could also use a single reflection spectrum to deduce optical constants as in this work and which was introduced by Minkov [21].

In this article, we start by calculating for I_x (As₂₀Se₈₀)_100-x (where x=0, 4, 8, 12, 16 at. %) the mean coordination number (N_C), the constraints number (Ns), the cohesion energy CE, the heat of atomization Hs, the mean overall bonding energy and then propose theoretical estimations of the band gap based on Manca's relation. The experimental evaluation of different linear and nonlinear optical features is then deduced from single reflection spectrum.

Section snippets

Theoretical estimation of different properties

Taking into account the element's bonding manner in their neighborhood as well as their coordination number which could be deduced from the 8-N rule, one could calculate an important structural parameter, the so called mean coordination number N_c for our ternary glasses I_x(As₂₀Se₈₀)_100-x (0 ≤ x ≤ 16 at. %) using the following relation: $N_{c} = (100 - x) \cdot N_{c} (A s_{20} S e_{80}) + x \cdot N_{c} (I)$

The needed coordination numbers of the involved elements As, Se, and I as well as their different physical properties used in this

Experimental details

The common melt quenching method was used to prepare different compositions of bulk glassy chalcogenides I_x(As₂₀Se₈₀)_100-x where (0 ≤ x ≤ 16 at. %). High purity (5N) elements from Sigma–Aldrich were introduced into pre-cleaned silica tubes in proper amounts. A high precision balance was used for this purpose. The sample's tubes were continously evacuated down to 5 × 10⁻⁵ Torr, then sealed off also under vacuum. The ampoules were introduced in a programmable oven, where the rate of heating 20

Results and discussion

The measured reflectance spectra for the deposited thin films of I_x(As₂₀Se₈₀)_100-x, R(λ), and the glass substrate, R_s(λ) are represented both in Fig. 1 simultaneously with the created envelopes R_M and R_m as supported by the study of Manifacier et al. [39]. Minkov [21] gave an analyzing method to evaluate from the maxima and minima of the interference fringes the film thickness and the index of refraction (n) of the deposited thin films. This method was widely applied in other chalcogenide

Conclusions

Incorporation of iodine at different contents in As₂₀Se₈₀ was achieved by the melt quenching technique and different thins films of I_x (As₂₀Se₈₀)_100-x (x=0, 4, 8, 12, 16 at. %) were thermally evaporated. After estimating theoretically different structural, energetic and optical features, one deduced the linear and nonlinear optical properties using single reflection method. It was found that different relations deduced from Manca's relation give good estimations of the decreasing experimental

CRediT authorship contribution statement

R. Neffati: Writing - original draft, Writing - review & editing. Imed Boukhris: Visualization. Imen Kebaili: Validation. K.A. Aly: Methodology. Y.B. Saddeek: Conceptualization. A. Dahshan: Supervision.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for financial support through research groups program under grant number (R.G. P2/81/41).

References (53)

A. Dahshan et al.
Optical constants of Ge-Sb-Se-I chalco-halide glasses using a single reflectance spectrum
Infrared Phys. Technol.
(2019)
C. Jiang et al.
Improvements on the optical properties of Ge–Sb–Se chalcogenide glasses with iodine incorporation
Infrared Phys. Technol.
(2015)
M. Guignard et al.
Optical and structural properties of new chalcohalide glasses
J. Non Cryst. Solids
(2008)
S.M. Lima et al.
Thermal and optical properties of chalcohalide glass
J. Non Cryst. Solids
(2001)
Z. Wang et al.
Synthesis and spectroscopy of high concentration dysprosium doped GeS2Ga2S3CdI2 chalcohalide glasses and fiber fabrication
J. Alloys Compd.
(2017)
C. Florea et al.
Surface relief gratings in AsSe glass fabricated under 800-nm laser exposure
Mater. Lett.
(2007)
J.C. Mauro et al.
Multiscale modeling of arsenic selenide glass
J. Non Cryst. Solids
(2007)
J.C. Phillips et al.
Constraint theory, vector percolation and glass formation
Solid State Commun.
(1985)
J.C. Phillips et al.
Constraint theory, vector percolation and glass formation
Solid State Commun.
(1985)
L. Zhenhua
Chemical bond approach to the chalcogenide glass forming tendency
J. Non-Cryst. Solids
(1991)

I. Boukhris et al.

Optical constants of Sn-doped amorphous Ge-As-Te thin films and their physical characterization

Physica B

(2020)

L. Tichy et al.

The composition dependence of the gap in amorphous films of Si_xGe_1-x, Sb_xSe_1-x and AsxTe_1-x systems

Solid State Commun.

(1982)

J. Bicerano et al.

Chemical bond approach to glass structure

J. Non-Cryst. Solids

(1985)

J. Bicerano et al.

Chemical bond approach to the structures of chalcogenide glasses with reversible switching properties

J. Non-Cryst. Solids

(1985)

L. Tichy et al.

Covalent bond approach to the glass-transition temperature of chalcogenide glasses

J. Non Cryst. Solids

(1995)

A. Dahshan et al.

Characterization of new quaternary Ge 20 Se 60 Sb 20−x Ag x (0 ≤ x ≤ 20 at.%) glasses

J. Non Cryst. Solids

(2015)

L. Tichý et al.

The composition dependence of the gap in amorphous films of SixGe1− x, SbxSe1− x and AsxTe1− x systems

Solid State Commun.

(1982)

P. Manca

A relation between the binding energy and the band-gap energy in semiconductors of diamond or zinc-blende structure

J. Phys. Chem. Solids

(1961)

A. Dahshan

Optical and other physical characteristics of Ge–Se–Cd thin films

Opt. Mater.

(2009)

K. Tanaka

Optical properties and photoinduced changes in amorphous AsS films

Thin Solid Films

(1980)

D. Minkov et al.

Optical properties of Ge-As-S thin films

J. Non Cryst. Solids

(1987)

K.A. Aly et al.

Optical constants of thermally evaporated Se–Sb–Te films using only their transmission spectra

Mater. Chem. Phys.

(2009)

H. Fritzsche

Density-of-states distribution in the mobility gap of a-Si:H

J. Non Cryst. Solids

(1985)

J. Lucas

Chalcohalide glasses

R. Balda, M. Sanz, A. Mendioroz, J. Fernandez, L. Griscom, J.-L.J.P.R.B. Adam, Infrared-to-visible upconversion in Nd...

A.R. Hilton, Chalcogenide glasses for infrared optics,...

Cited by (9)

Research on a novel chalcohalide glass and its physical optics properties
2022, Infrared Physics and Technology
Citation Excerpt :
As we all know, the introduced halogen elements will not only doesn’t import extra infrared impurity absorption peak, but also can increase the IR transmission rate of chalcogenide glasses. Several chalcohalide glasses have been reported in S-based [17,18], Se-based [19,20] and Te-based [21] chalcogenide glasses. Among these conventional chalcohalide glasses, the ZDWs of Se-[22] and Te-based [23,24] glasses are generally above 6 μm.
Two series of novel chalcohalide glasses varying on different molar percentages of cations and anions were prepared successfully. We experimentally investigated the physical optics properties of the chalcohalide hybrid glass (Ge-As-S-Se-I) system. The results show that the short-wavelength cut-off edge (λ_vis), linear refractive index (n₀), and zero-dispersion-wavelength (ZDW) regularly decrease with the increase of anionic iodine mole percentage. And the addition of cationic germanium enhances the glass transition temperature (T_g), softening temperature (T_p) and crystallization temperature (T_x). Besides, a mono-index optical fiber was drawn successfully using the high temperature polymer as the protective layer, with a minimum loss of 1.91 dB/m at 2.6 μm. Supercontinuum (SC) covering 1.01 ∼ 8.32 μm was generated by pumping the 10-cm-long fiber at a femtosecond laser of 3.78 μm (∼150 fs, 1 kHz, 20 mW). This novel infrared (IR) glass shows great potential in many applications, such as defense military, spectroscopy, long-distance remote sensing.
DC conductivity and threshold switching in iodine doped Ge-Se-Te glasses
2021, Ceramics International
Citation Excerpt :
Te rich glasses in Ge-Se-Te system show higher transparency in the IR region even beyond 15 μm [18]. The addition of halogen, particularly iodine (I) with large atomic radius 133 p.m. and a low melting point of 113.7 °C into chalcogenide glasses, prevents crystallization, which improves the glass-forming ability [19]. So, here we report the dc conductivity and threshold switching in iodine doped Ge-Se-Te glasses.
The composition and temperature-dependent dc conductivity of (Ge₂₀Se₁₈Te₆₂)_100-xI_x (x = 0 and 8) glasses have been studied. The activation energy at constant current decreases, whereas with composition, it increases. The I–V characteristic curves for the glassy compositions show threshold switching. Iodine content shows a remarkable effect when introduced in Ge-Se-Te glasses on the switching properties. Variation in the threshold voltage (V_th) with composition decreased from 334 to 308 V. The thickness and temperature dependency on V_th is also examined. With increasing temperature, the V_th decreases exponentially, whereas it increases as T² with an increase in the thickness of the glass samples. The thermal breakdown ΔT_breakdown is also calculated. The threshold switching properties may be explored for numerous applications such as high-speed electronic memory and selector devices.
Elastic moduli and theoretical estimations of physical properties of Ge<inf>3</inf>Se<inf>7</inf>–As<inf>2</inf>Te<inf>3</inf>
2021, Current Applied Physics
Citation Excerpt :
Yamaguchi [41] proposed a linear relationship that connected Eg with the heat of atomization (Hs). So, the rigidity parameters such as the mean bond energy (Es), the cohesive energy (CE), and the overall average bond energy (<E>) can be used to estimate the Eg Refs. [10,35,42]. Furthermore, the chemical-bond approach (CBA) [43] is also utilized to expect the type and distribution of bonds that occurred in the glasses, and then one can estimate the Eg Refs. [36,37].
The Bulk (100-x)Ge₃Se₇ - (x)As₂Te₃ (0 ≤ x ≤ 30) glassy alloys were prepared using the melt quenching technique. The elastic moduli (Bulk (K), Micro-hardness (H), Young (Y)), and Poisson's ratio (P_r) of the prepared glasses have been determined using the measured values of the ultrasonic velocities and density (ρ). Values of ρ were measured, then the molar volume (V_m) was estimated theoretically. The DSC thermograms are used to determine the glass transition temperature (T_g). The thermal evaporation method was used to prepare the (100-x)Ge₃Se₇- (x)As₂Te₃ (0 ≤ x ≤ 30) thin films under a vacuum of about 10⁻⁴Pa. The absorbance (A) of the films in the spectral range from 0.45 to 0.85 μm has been measured, then the absorption coefficient (α) and energy gap (E_g) were determined. The Chemical Bond Approach (CBA) has been used successfully to estimate theoretically various physical and structural characteristics of the studied system. Theoretical values of E_g and T_g have been obtained using different methods. The results proved a remarkable agreement between the theoretical and experimental values for both the E_g and T_g. The E_g values decreased from 2.1 to 1.73 eV by increasing the As₂Te₃ content from 0 to 30 at. %. Therefore, these compounds can be used as an absorbing layer for electromagnetic radiation in photovoltaic devices and sensors.
Mechanical properties and band gap estimations of stoichiometric GeSe<inf>2</inf>-As<inf>2</inf>Se<inf>3</inf> glasses
2021, Optik
Citation Excerpt :
Various physical factors such as CE, Es, < E > , and the whole difference of electronegativity (Δχ), as well as the degree of both ionicity (Ion) and covalency (Cov) were determined using some physical parameters of bonds. These parameters are type and quantity that arisen in ChGs [9,10,31,39]. Also, the theoretical calculation of energy gap by utilizing the concept of distributions of the chemical bonds had been evaluated [32,33].
The elastic moduli (Bulk (K_e), Micro-hardness (H_e), Young (Y_e)) and Poisson’s ratio (P_r) of the prepared xGeSe₂-(100-x)As₂Se₃ (0 ≤ x ≤ 100) glasses are estimated using the ultrasonic velocities (Longitudinal (ν_l) and Transverse wave (ν_t)) and the density (ρ). The glass transition temperature (T_g) of the glasses has been obtained using the DSC thermograms recorded at a heating rate 10 K/min. As well, many physical and structural features have been obtained theoretically by applying the Chemical Bond Approach (CBA). Theoretical evaluations of optical band-gap (E_g) and the glass-transition temperature (T_g) for the glasses have been studied. It was found that the obtained theoretical values of the parameters E_g and T_g agree with the experimental values within uncertainty < 4%. Also, rigidity parameters such as the heat of atomization (H_s), the mean bond energy (E_s), the cohesive energy (CE), and the overall average bond energy (< E > ) have been estimated. The dependence of E_g on the rigidity parameters (H_s, E_s, CE, and < E > ) was verified and discussed. Furthermore, the coordination number (CN), lone pair electrons (LP), and crosslinking density (CD) were estimated. E_g values increased from 1.6 to 2.04 eV with increasing the GeSe₂ concentration from 0 to 100 at%. So, these materials can be used as optical absorbers in solar cells and sensors.
Synthesis and theoretical characterization of ternary Cu<inf>x</inf>(Ge<inf>30</inf>Se<inf>70</inf>)<inf>100−x</inf> glasses
2021, Results in Physics
The Cu_x(Ge₃₀Se₇₀)_100−x (0 ≤ x ≤ 12 at.%) chalcogenide alloys have been synthesized by the conventional melt quenching technique. The physical properties such as the mean coordination number, density, molar volume, compactness, overall bond energy, and cohesive energy were estimated for the Cu doped Ge-Se glassy alloys. The chemical bond approach (CBA) was used to predict the type and proportion of the formed bonds in the studied glasses. Subsequently, several structural and physical properties have been estimated. The results show that the studied glasses are rigidly connected, having an average coordination number increase from 2.6 to 2.77. The density and glass compactness show an increase with the Cu content, whereas the main atomic volume decreases. The cohesive energy and the heat of atomization show a similar behavior trend with the enhancement of Cu % in the Ge-Se binary glasses. The optical band gap was estimated theoretically compared with the previously published experimental values for the Cu_x(Ge₃₀Se₇₀)_100−x (0 ≤ x ≤ 12 at.%) thin films. The covalency parameter >91% for the studied glasses so that the compositions may be used as a stable glass former. Furthermore, the mechanical properties as the elastic bulk modulus, Poisson’s ratio, Young’s modulus, micro-hardness, and Debye temperature were investigated as a function of the Cu content.
Assessment of linear/nonlinear optical constants and dispersion parameters of Se<inf>85−x</inf>Te<inf>15</inf>Sb<inf>x</inf> glasses for photonic applications
2021, Optical Materials
The effect of $S b a t %$ on structural and linear/nonlinear optical properties was studied theoretically and experimentally for $S e_{85 - x} T e_{15} S b_{x}$ ( $x = 10, 12.5 a n d 15 a t %$ ) glasses. The structural characterization was examined using EDX, XRD, DTA and FTIR. The calculated mean coordination number $N_{C N}$ , average constraints number $N_{s}$ , overall mean bond energy $E_{b}$ and average heat of atomization $H_{S}$ increase with $S b a t %$ , which reflects an increase in the system rigidity and correlated to the increase in crosslinking with Sb at%. The linear/nonlinear optical constants such as optical energy gap $E_{g}$ , Urbach's energy $E_{e}$ , linear refractive index $n$ , nonlinear refractive index $n_{2}$ , the third order susceptibility $χ^{(3)}$ and the electronic polarizability $α_{p}$ are all evaluated and discussed for the studied films. The dispersion parameters were analyzed using Wemple-DiDomenico model of single oscillator model and the optical/electrical/thermal conductivities and electronic properties were deduced. The optical energy gap $E_{g}$ , optical conductivities $σ_{o p t}$ and single oscillator energy $E_{o}$ decreased while the Urbach's energy $E_{e}$ and the refractive index $n$ increased with $S b a t %$ . Assessment of linear/nonlinear and other optical and physical parameters shows that $S e_{70} T e_{15} S b_{15}$ could be a candidate for several photonic applications.

View all citing articles on Scopus

View full text

Effect of iodine content on optical properties of chalcohalide glasses Ix(As20Se80)100-x

Highlights

Abstract

Introduction

Section snippets

Theoretical estimation of different properties

Experimental details

Results and discussion

Conclusions

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgement

Infrared Phys. Technol.

Infrared Phys. Technol.

J. Non Cryst. Solids

J. Non Cryst. Solids

J. Alloys Compd.

Mater. Lett.

J. Non Cryst. Solids

Solid State Commun.

Solid State Commun.

J. Non-Cryst. Solids

Physica B

Solid State Commun.

J. Non-Cryst. Solids

J. Non-Cryst. Solids

J. Non Cryst. Solids

J. Non Cryst. Solids

Solid State Commun.

J. Phys. Chem. Solids

Opt. Mater.

Thin Solid Films

J. Non Cryst. Solids

Mater. Chem. Phys.

J. Non Cryst. Solids

Chalcohalide glasses

Effect of iodine content on optical properties of chalcohalide glasses I_x(As₂₀Se₈₀)_100-x