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Formation and structure of crystalline inclusions in As2S3–SbSI and As2Se3–SbSI systems glass matrices
Journal of Non-Crystalline Solids 357 (2011) 2232–2234
Contents lists available at ScienceDirect
Journal of Non-Crystalline Solids j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j n o n c r y s o l
Formation and structure of crystalline inclusions in As2S3–SbSI and As2Se3–SbSI systems glass matrices M. Barj a,⁎, O.A. Mykaylo b, D.I. Kaynts b, O.V. Gorina c, O.G. Guranich c, V.M. Rubish c a b c
Université Lille1 Sciences et Technologies, LASIR, C5, 59655 Villeneuve d'Ascq Cedex, France Uzhgorod National University, Uzhgorod, Ukraine Uzhgorod Scientific-Technological Center of the Institute for Information Recording, NASU, Uzhgorod, Ukraine
a r t i c l e
i n f o
Article history: Received 13 July 2010 Received in revised form 4 October 2010 Available online 27 December 2010 Keywords: Raman; Diffraction; Chalcogenide glasses; Ferroelectrics
a b s t r a c t The main aim of the study presented in this paper is the investigation of the structure of (As2S3)100−x(SbSI)x and (As2Se3)100−x(SbSI)x (0 ≤ × ≤ 40) glasses by Raman spectroscopy and X-ray methods, also the nature of the crystalline inclusions which arise up in their matrix at heat treatment. We have found that in conditions of continuous heating in the interval “glassforming temperature–crystallization temperature” a crystallization with predominant mechanism of stable phase SbSI separation is taking place. The formation mechanism of crystalline inclusions of antimony sulphoiodide in glass matrix is discussed in the light of our results. It was established that all investigated glasses have a nano-heterogeneous structure. © 2010 Elsevier B.V. All rights reserved.
1. Introduction The possibility of practical application attracts the interest to the non-crystalline materials whose crystalline analogues possess pronounced ferroelectric properties. The glasses on the basis of SbSI (antimony sulphoiodide) which in crystalline state is distinctly defined as ferroelectric-semiconductors are very promising in this aspect. Some anomalies, related to the transition of glasses to the polar state and their next crystallization were found at the research of temperature dependences of dielectric parameters (ε and tg δ) for chalcogenide glasses from As2S3–SbSI and As2Se3−SbSI systems with a content of antimony sulphoiodide higher than 50 mol% in the temperature range Tg−Tc (Tg, Tc — temperatures of vitrification and crystallization, accordingly) [1–3]. Crystallization of glasses is accompanied by a sharp growth of ε. Investigations of X-ray powder diffraction patterns and Raman spectra of crystallized glasses have demonstrated the structure of phase, which arises up in a glassy matrix, related to the structure of crystalline SbSI [3,4]. The dimensions of crystalline inclusions, and accordingly, of dielectric parameters of obtained ferroelectric glassceramics, depend on the temperature and annealing time. For example, the values of dielectric permittivity ε for (As2S3)10(SbSI)90 and (As2Se3)20(SbSI)80 samples after isothermal annealing during 5 h at temperatures 410 K and 423 K, accordingly, during the 5-hour
⁎ Corresponding author. Tel.: +33 3 20 33 59 95; fax: +33 3 20 43 67 55. E-mail address: [email protected] (M. Barj). 0022-3093/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2010.11.095
growth to 50–70 units [3]. The dimensions of crystalline inclusions in the glassy matrix are insignificant and they are formed at the annealing temperatures below 410 K and 423 K, respectively, and for a short annealing time. However, the production of ferroelectric nanoceramics on the basis of these materials is complicated by the presence of a high content of antimony sulphoiodide in their composition and a high-rate of growth of SbSI crystals [1]. In this aspect the ferroelectric glass-ceramics with nanosize inclusions on the basis of insufficiently known glasses from As2S3– SbSI and As2Se3− SbSI systems with a small content of antimony sulphoiodide (up to 50 mol%) attract an obvious interest. 2. Experimental Glassy alloys (As2S 3) 100−x(SbSI)x and (As 2 Se3 )100−x(SbSI) x (0 ≤ × ≤ 40) glasses were prepared by vacuum melting method of the corresponding components mixture of As2S3, As2Se3 and SbSI components which had been synthesized before from a high purity elementary substances. SbSI was obtained in polycrystalline form by slow cooling of a melt subjected after a homogenization at 900 K during 72 h. As2S3 and As2Se3 glasses were obtained by cooling at ambient air. Their melts were homogenized at 780 and 800 K, accordingly, during 48 h. (As2S3)100−x(SbSI)x and (As2Se3)100−x (SbSI)x melts were homogenized for 24 h at 720–870 K and 800– 870 K, accordingly. The melts were periodically stirred. Cooling of the melts was carried out on the air. X-ray diffraction studies for glassy, crystallized glasses and polycrystalline SbSI were carried out on a DRON-3 diffractometer, CuKα-radiation (λ = 1.5418 Å) being applied. Raman spectra were
M. Barj et al. / Journal of Non-Crystalline Solids 357 (2011) 2232–2234
2233
I, a.u.
3
2
1
20
30
40
50
2Θ, degree Fig. 1. X-ray powder diffraction patterns of polycrystalline SbSI (1), as-prepared (2) crystallized and (3) at T = 403 K for 48 h (As2S3)60(SbSI)40 glasses.
obtained using a confocal LABRAM micro-spectrometer and a He–Ne cw-laser (λ = 632.8 nm, 1.96 eV). The low frequency Spectra were obtained using a Dilor XY spectrometer in a 90° configuration. The power of the exciting line was set as low as possible to avoid photostructural changes in the sample [5,6].
3. Results and discussion It was aforementioned that glasses from these systems with small content of SbSI (up to 50 mol%) and the products of their crystallization practically were not been studied. All investigated asprepared glasses were without crystalline inclusions according to the X-ray studies (Figs. 1 and 2, curves 2). The glasses of (As2S3)100−x (SbSI)x system were annealed at T1 = 403 K and (As2Se3)100−x(SbSI)x system at T2 = 393 K. These temperatures were selected taking into account the data of differential thermal analysis. Figs. 1 and 2 (curves 2) show the X-ray powder diffraction patterns of (As2S3)60(SbSI)40 and (As2Se3)70(SbSI)30 glasses after annealing at T1 and T2 for 48 and 8 h, respectively, which testify to the presence of a crystalline phase. In the same figures X-ray powder diffraction patterns of polycrystalline SbSI (curves 1) were shown. It is evident, that the positions of weak X-ray reflections for crystallized glasses
Fig. 3. Raman spectra of as-prepared (As2S3)100−x(SbSI)x glasses. x, mol%: 1–0; 2–2; 3–5; 4–10; 5–20; 6–30; and 7–40.
coincide with the positions of intensive bands on the X-ray powder diffraction pattern for polycrystalline SbSI. It shows that the structure of phase, which is formed in the matrix of glasses at their annealing correspond to the structure of crystalline antimony sulphoiodide. The strong reflection diffusion on the X-ray powder diffraction patterns for crystallized glasses testifies to the very small dimensions (a few nm) of the crystalline inclusions of SbSI. The nanoinclusions for (As2S3)100−x(SbSI)x (where x ≤ 30) and (As2Se3)100−x(SbSI)x (where x ≤ 20) glasses have not been fixed by these research methods at these annealing conditions. With the purpose of confirmation of this affirmation the Raman spectra of glasses and crystallization products of their basis were performed. Raman spectra of the as-prepared glasses are significantly modified with the SbSI content increase. The glassy matrix is formed by structural groups consisting of AX3/2 (A As, Sb and X S, Se), AI3 and also contains molecular fragments with homopolar A–A and X–X bonds. As shown in figs. 3 and 4, an important frequency shift is observed for the strong broad components at 340 cm− 1 (sulphide system) and
3
I, a.u.
2
1 20
40
2Θ, degree Fig. 2. X-ray powder diffraction patterns of polycrystalline SbSI (1), as-prepared (2) crystallized and (3) at T = 393 K for 8 h (As2Se3)70(SbSI)30 glasses.
Fig. 4. Raman spectra of as-prepared (As2Se3)100−x(SbSI)x glasses. x, mol.%: 1–0; 2–2; 3–5; 4–10; 5–20; and 6–30.
2234
M. Barj et al. / Journal of Non-Crystalline Solids 357 (2011) 2232–2234
crystallized glasses. The spectra of crystallized glasses have intensive bands in the range of 50–200 cm− 1, which are in a good agreement with band positions in polycrystalline SbSI (Fig. 5, inset). The formation mechanism of crystalline inclusions could be offered. The presence of several types of structural groups in the glass matrix lead to the interaction and deformation in it, then, as results, to the considerable nonequivalence of distances and binding forces between atoms. At the same time, during the heating process, the structural lattice lability even grows more, and there exists the possibility of Sb–S, Sb–I, As–I, As–S(Se), and S(Se)–S(Se) chemical bonds breaking the rearrangement in these binary structural groups in the temperature range from Tg to Tc . This process is accompanied by the diffusion of atoms at distances of the interatomic order. As a result, the triple chain groups that are typical for crystalline antimony sulphoiodide are formed.
4. Conclusion
Fig. 5. Raman spectra of (As2Se3)70(SbSI)30 glasses crystallized at T = 393 K for 8 h. (1), (As2S3)40(SbSI)60 one crystallized at T = 403 K for 48 h and (2) polycrystalline SbSI (inset).
224 cm− 1 (selenide system) of the ν( A–S) and ν( A–Se) modes within the AX3/2 pyramids [3,5,6]. The highest shift is observed for 20 ≤ × ≤ 40 for both systems. For the highest content of SbSI, two strong bands are observed at about 170 cm−1 and 209 cm−1 could be associated to the stretching and bending vibrational modes involving Iodine and Antimony atoms, also Iodine and Arsenic ones, respectively [3,7]. The Raman spectra of these as-prepared samples do not show any bands due to the presence of crystalline SbSI in the glassy matrix. This is in agreement with the X-ray diffraction results. Raman spectra of (As2Se3)70(SbSI)30 glasses crystallized at T = 393 K for 8 h, and (As2S3)40(SbSI)60 glasses crystallized at T = 403 K for 48 h are given in Fig. 5 (curves 1,2). Similar results were obtained for all (As2S3)100−x(SbSI)x (0≤ × ≤ 40) and (As2Se3)100−x(SbSI)x (0≤ × ≤ 30)
Glassy alloys (As2S3)100−x(SbSI)x (0 ≤ × ≤ 40) and (As2Se3)100−x (SbSI)x (0 ≤ × ≤ 30) glasses were prepared and investigated by X-Ray diffraction and Raman spectroscopy. The presence after annealing of weak reflections on X-ray powder diffraction patterns and intensive bands in the range of 50–200 cm− 1 on Raman spectra, at the same position of the diffraction lines and sharp bands of polycrystalline SbSI, indicates the presence of crystalline antimony sulphoiodide inclusions in the glassy matrix. The strong reflection diffusion on these diffractograms is probably due to the nanometric dimensions of the inclusions.
References [1] V.M. Rubish, J. Optoelectron. Adv. Mater. 3 (2001) 941. [2] V.M. Rubish, Sensors electronics microsystems technologies 1 (2007) 62. [3] D.I. Kaynts, A.P. Shpak, V.M. Rubish, O.A. Mykaylo, O.G. Guranich, P.P. Shtets, P.P. Guranich, Ferroelectr. 371 (2008) 28. [4] V.M. Rubish, Phys. Chem. Solid State 8 (1987) 35. [5] V.K. Tikhomirov, M. Barj, S. Turrell, Philos. Mag. Lett. 85 (2005) 325. [6] V.K. Tichomirov, M. Barj, S. Turrell, J. Kobelke, N. Idrissi, M. Bouazaoui, B. Capoen, A.B. Seddon, Europhys. Lett. 76 (2006) 312. [7] L. Koudelká, M. Pisárćik, Solid State Commun. 41 (1982) 115.
Contents lists available at ScienceDirect
Journal of Non-Crystalline Solids j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j n o n c r y s o l
Formation and structure of crystalline inclusions in As2S3–SbSI and As2Se3–SbSI systems glass matrices M. Barj a,⁎, O.A. Mykaylo b, D.I. Kaynts b, O.V. Gorina c, O.G. Guranich c, V.M. Rubish c a b c
Université Lille1 Sciences et Technologies, LASIR, C5, 59655 Villeneuve d'Ascq Cedex, France Uzhgorod National University, Uzhgorod, Ukraine Uzhgorod Scientific-Technological Center of the Institute for Information Recording, NASU, Uzhgorod, Ukraine
a r t i c l e
i n f o
Article history: Received 13 July 2010 Received in revised form 4 October 2010 Available online 27 December 2010 Keywords: Raman; Diffraction; Chalcogenide glasses; Ferroelectrics
a b s t r a c t The main aim of the study presented in this paper is the investigation of the structure of (As2S3)100−x(SbSI)x and (As2Se3)100−x(SbSI)x (0 ≤ × ≤ 40) glasses by Raman spectroscopy and X-ray methods, also the nature of the crystalline inclusions which arise up in their matrix at heat treatment. We have found that in conditions of continuous heating in the interval “glassforming temperature–crystallization temperature” a crystallization with predominant mechanism of stable phase SbSI separation is taking place. The formation mechanism of crystalline inclusions of antimony sulphoiodide in glass matrix is discussed in the light of our results. It was established that all investigated glasses have a nano-heterogeneous structure. © 2010 Elsevier B.V. All rights reserved.
1. Introduction The possibility of practical application attracts the interest to the non-crystalline materials whose crystalline analogues possess pronounced ferroelectric properties. The glasses on the basis of SbSI (antimony sulphoiodide) which in crystalline state is distinctly defined as ferroelectric-semiconductors are very promising in this aspect. Some anomalies, related to the transition of glasses to the polar state and their next crystallization were found at the research of temperature dependences of dielectric parameters (ε and tg δ) for chalcogenide glasses from As2S3–SbSI and As2Se3−SbSI systems with a content of antimony sulphoiodide higher than 50 mol% in the temperature range Tg−Tc (Tg, Tc — temperatures of vitrification and crystallization, accordingly) [1–3]. Crystallization of glasses is accompanied by a sharp growth of ε. Investigations of X-ray powder diffraction patterns and Raman spectra of crystallized glasses have demonstrated the structure of phase, which arises up in a glassy matrix, related to the structure of crystalline SbSI [3,4]. The dimensions of crystalline inclusions, and accordingly, of dielectric parameters of obtained ferroelectric glassceramics, depend on the temperature and annealing time. For example, the values of dielectric permittivity ε for (As2S3)10(SbSI)90 and (As2Se3)20(SbSI)80 samples after isothermal annealing during 5 h at temperatures 410 K and 423 K, accordingly, during the 5-hour
⁎ Corresponding author. Tel.: +33 3 20 33 59 95; fax: +33 3 20 43 67 55. E-mail address: [email protected] (M. Barj). 0022-3093/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2010.11.095
growth to 50–70 units [3]. The dimensions of crystalline inclusions in the glassy matrix are insignificant and they are formed at the annealing temperatures below 410 K and 423 K, respectively, and for a short annealing time. However, the production of ferroelectric nanoceramics on the basis of these materials is complicated by the presence of a high content of antimony sulphoiodide in their composition and a high-rate of growth of SbSI crystals [1]. In this aspect the ferroelectric glass-ceramics with nanosize inclusions on the basis of insufficiently known glasses from As2S3– SbSI and As2Se3− SbSI systems with a small content of antimony sulphoiodide (up to 50 mol%) attract an obvious interest. 2. Experimental Glassy alloys (As2S 3) 100−x(SbSI)x and (As 2 Se3 )100−x(SbSI) x (0 ≤ × ≤ 40) glasses were prepared by vacuum melting method of the corresponding components mixture of As2S3, As2Se3 and SbSI components which had been synthesized before from a high purity elementary substances. SbSI was obtained in polycrystalline form by slow cooling of a melt subjected after a homogenization at 900 K during 72 h. As2S3 and As2Se3 glasses were obtained by cooling at ambient air. Their melts were homogenized at 780 and 800 K, accordingly, during 48 h. (As2S3)100−x(SbSI)x and (As2Se3)100−x (SbSI)x melts were homogenized for 24 h at 720–870 K and 800– 870 K, accordingly. The melts were periodically stirred. Cooling of the melts was carried out on the air. X-ray diffraction studies for glassy, crystallized glasses and polycrystalline SbSI were carried out on a DRON-3 diffractometer, CuKα-radiation (λ = 1.5418 Å) being applied. Raman spectra were
M. Barj et al. / Journal of Non-Crystalline Solids 357 (2011) 2232–2234
2233
I, a.u.
3
2
1
20
30
40
50
2Θ, degree Fig. 1. X-ray powder diffraction patterns of polycrystalline SbSI (1), as-prepared (2) crystallized and (3) at T = 403 K for 48 h (As2S3)60(SbSI)40 glasses.
obtained using a confocal LABRAM micro-spectrometer and a He–Ne cw-laser (λ = 632.8 nm, 1.96 eV). The low frequency Spectra were obtained using a Dilor XY spectrometer in a 90° configuration. The power of the exciting line was set as low as possible to avoid photostructural changes in the sample [5,6].
3. Results and discussion It was aforementioned that glasses from these systems with small content of SbSI (up to 50 mol%) and the products of their crystallization practically were not been studied. All investigated asprepared glasses were without crystalline inclusions according to the X-ray studies (Figs. 1 and 2, curves 2). The glasses of (As2S3)100−x (SbSI)x system were annealed at T1 = 403 K and (As2Se3)100−x(SbSI)x system at T2 = 393 K. These temperatures were selected taking into account the data of differential thermal analysis. Figs. 1 and 2 (curves 2) show the X-ray powder diffraction patterns of (As2S3)60(SbSI)40 and (As2Se3)70(SbSI)30 glasses after annealing at T1 and T2 for 48 and 8 h, respectively, which testify to the presence of a crystalline phase. In the same figures X-ray powder diffraction patterns of polycrystalline SbSI (curves 1) were shown. It is evident, that the positions of weak X-ray reflections for crystallized glasses
Fig. 3. Raman spectra of as-prepared (As2S3)100−x(SbSI)x glasses. x, mol%: 1–0; 2–2; 3–5; 4–10; 5–20; 6–30; and 7–40.
coincide with the positions of intensive bands on the X-ray powder diffraction pattern for polycrystalline SbSI. It shows that the structure of phase, which is formed in the matrix of glasses at their annealing correspond to the structure of crystalline antimony sulphoiodide. The strong reflection diffusion on the X-ray powder diffraction patterns for crystallized glasses testifies to the very small dimensions (a few nm) of the crystalline inclusions of SbSI. The nanoinclusions for (As2S3)100−x(SbSI)x (where x ≤ 30) and (As2Se3)100−x(SbSI)x (where x ≤ 20) glasses have not been fixed by these research methods at these annealing conditions. With the purpose of confirmation of this affirmation the Raman spectra of glasses and crystallization products of their basis were performed. Raman spectra of the as-prepared glasses are significantly modified with the SbSI content increase. The glassy matrix is formed by structural groups consisting of AX3/2 (A As, Sb and X S, Se), AI3 and also contains molecular fragments with homopolar A–A and X–X bonds. As shown in figs. 3 and 4, an important frequency shift is observed for the strong broad components at 340 cm− 1 (sulphide system) and
3
I, a.u.
2
1 20
40
2Θ, degree Fig. 2. X-ray powder diffraction patterns of polycrystalline SbSI (1), as-prepared (2) crystallized and (3) at T = 393 K for 8 h (As2Se3)70(SbSI)30 glasses.
Fig. 4. Raman spectra of as-prepared (As2Se3)100−x(SbSI)x glasses. x, mol.%: 1–0; 2–2; 3–5; 4–10; 5–20; and 6–30.
2234
M. Barj et al. / Journal of Non-Crystalline Solids 357 (2011) 2232–2234
crystallized glasses. The spectra of crystallized glasses have intensive bands in the range of 50–200 cm− 1, which are in a good agreement with band positions in polycrystalline SbSI (Fig. 5, inset). The formation mechanism of crystalline inclusions could be offered. The presence of several types of structural groups in the glass matrix lead to the interaction and deformation in it, then, as results, to the considerable nonequivalence of distances and binding forces between atoms. At the same time, during the heating process, the structural lattice lability even grows more, and there exists the possibility of Sb–S, Sb–I, As–I, As–S(Se), and S(Se)–S(Se) chemical bonds breaking the rearrangement in these binary structural groups in the temperature range from Tg to Tc . This process is accompanied by the diffusion of atoms at distances of the interatomic order. As a result, the triple chain groups that are typical for crystalline antimony sulphoiodide are formed.
4. Conclusion
Fig. 5. Raman spectra of (As2Se3)70(SbSI)30 glasses crystallized at T = 393 K for 8 h. (1), (As2S3)40(SbSI)60 one crystallized at T = 403 K for 48 h and (2) polycrystalline SbSI (inset).
224 cm− 1 (selenide system) of the ν( A–S) and ν( A–Se) modes within the AX3/2 pyramids [3,5,6]. The highest shift is observed for 20 ≤ × ≤ 40 for both systems. For the highest content of SbSI, two strong bands are observed at about 170 cm−1 and 209 cm−1 could be associated to the stretching and bending vibrational modes involving Iodine and Antimony atoms, also Iodine and Arsenic ones, respectively [3,7]. The Raman spectra of these as-prepared samples do not show any bands due to the presence of crystalline SbSI in the glassy matrix. This is in agreement with the X-ray diffraction results. Raman spectra of (As2Se3)70(SbSI)30 glasses crystallized at T = 393 K for 8 h, and (As2S3)40(SbSI)60 glasses crystallized at T = 403 K for 48 h are given in Fig. 5 (curves 1,2). Similar results were obtained for all (As2S3)100−x(SbSI)x (0≤ × ≤ 40) and (As2Se3)100−x(SbSI)x (0≤ × ≤ 30)
Glassy alloys (As2S3)100−x(SbSI)x (0 ≤ × ≤ 40) and (As2Se3)100−x (SbSI)x (0 ≤ × ≤ 30) glasses were prepared and investigated by X-Ray diffraction and Raman spectroscopy. The presence after annealing of weak reflections on X-ray powder diffraction patterns and intensive bands in the range of 50–200 cm− 1 on Raman spectra, at the same position of the diffraction lines and sharp bands of polycrystalline SbSI, indicates the presence of crystalline antimony sulphoiodide inclusions in the glassy matrix. The strong reflection diffusion on these diffractograms is probably due to the nanometric dimensions of the inclusions.
References [1] V.M. Rubish, J. Optoelectron. Adv. Mater. 3 (2001) 941. [2] V.M. Rubish, Sensors electronics microsystems technologies 1 (2007) 62. [3] D.I. Kaynts, A.P. Shpak, V.M. Rubish, O.A. Mykaylo, O.G. Guranich, P.P. Shtets, P.P. Guranich, Ferroelectr. 371 (2008) 28. [4] V.M. Rubish, Phys. Chem. Solid State 8 (1987) 35. [5] V.K. Tikhomirov, M. Barj, S. Turrell, Philos. Mag. Lett. 85 (2005) 325. [6] V.K. Tichomirov, M. Barj, S. Turrell, J. Kobelke, N. Idrissi, M. Bouazaoui, B. Capoen, A.B. Seddon, Europhys. Lett. 76 (2006) 312. [7] L. Koudelká, M. Pisárćik, Solid State Commun. 41 (1982) 115.