PHASE FORMATION IN THE AS2SE3-TL2S3 SYSTEM AND THE PHYSICO-CHEMICAL PROPERTIES OF THE OBTAINED PHASES Текст научной статьи по специальности «Химические науки»

CHEMICAL SCIENCES

PHASE FORMATION IN THE AS2Se3-TkS3 SYSTEM AND THE PHYSICO-CHEMICAL PROPERTIES OF THE OBTAINED PHASES

Aliyev I.,

Institute of Catalysis and Inorganic Chemistry named after M.F.Nagiyev of the National Academy of Sciences of Azerbaijan Ahmedova C.,

Adiyaman State University, Faculty of Arts and Sciences, Department of Chemistry, Turkey.

Rzaev R.,

Azerbaijan State University of Economics Gashimov Kh.

Azerbaijan State University of Economics

Abstract

Chemical interactions and glass formation in the As2Se3-Tl2S3 system were studied by the methods of physi-cochemical analysis: differential thermal analysis (DTA), X-ray phase analysis (XRD), microstructural analysis (MSA), as well as the determination of microhardness, density, and a T-x phase diagram was constructed. It has been established that the state diagram of the As2Se3-Tl2S3 system is partially quasi-binary, of the eutectic type. In the As2Se3-Tl2S3 system, a new quaternary compound Tl2As2S3Se3 is formed. The Tl2As2S3Se3 compound melts with an open maximum at 548 K. In the system As2Se3-T^S3 based on the As2Se3 compound, a solid solution is formed up to 3.5 mol % T^S3. Taking into account the peritectic character of the formation of the ThS3 compound, the region of the solid solution at its base is practically not established. As a result, during normal cooling in the system, the glass formation region reaches 65 mol % ThS3, and in the mode of quenching in liquid nitrogen, all alloys are obtained in a glassy state.

Keywords: system, glass, microhardness, quasi-binary, solid solution.

Introduction

Glassy arsenic chalcogenides and alloys based on them have attracted close attention of researchers in recent years. With the participation of arsenic chalcogen-ides, the obtained ternary phases have photoelectric [18], acousto-optic [9-11], and luminescent properties [12, 13].

Numerous systems of chemical interactions with thallium, arsenic, and other metal chalcogenides have been studied [14-20]. Due to photosensitivity, compounds and solid solutions based on thallium chalco-genides are materials with electrophysical properties [21-24].

The creation of physical and chemical bases for obtaining multicomponent complex chalcogenide glassy phases of variable composition with desired characteristics requires the study of phase equilibria in the corresponding systems.

This work is devoted to the study of physical and chemical studies of the As2Se3-Tl2S3 system, in order to obtain new glassy semiconductor phases of complex composition with desired properties.

Experimental part

Alloys of the system were synthesized from alloys As2Se3-Tl2S3 in quartz ampoules evacuated to 0.133 Pa at 873-973 K. Alloys of the system are low-melting and compact, black. The alloys were cooled slowly. The synthesized samples of the system were annealed at 210 and 353 K for 800 h. The physicochemical study of the system was carried out before and after annealing (Tables 1 and 2).

The DTA of the alloys of the system was carried out on an NTR-73 instrument at a rate of 10 deg/min.

XRF was performed on a D2 PHASER X-ray machine with CuKa radiation and a Ni filter. MSA of the alloys of the system was studied using a MIM-8 microscope on pre-etched sections polished with GOI paste. The microhardness of the system alloys was measured on a PMT-3 microhardness tester. The density of the alloys of the system was determined by the pycnometric method; toluene was used as a filler.

Results and its discussion

DTA of cast samples shows that alloys of the As2Se3-Tl2S3 system in the concentration range 0-65 mol % Tl2Ss are obtained in a glassy form. On the thermograms of these alloys, there are two types of softening temperatures. The value of Tg =443-453 K corresponds to the softening temperature of glasses based on As2Se3, and the value of Tg =403-438 K corresponds to the softening temperature of glasses based on Tl2Ae2S3Se3. To determine the area of glass formation, DTA, XRF, MSA measurements of microhardness and determination of the density of alloys of the As2Se3-Tl2S3 system were carried out before and after annealing.

The effect of heat treatment on the coefficient of expansion is particularly pronounced when comparing the expansion curves of well-annealed glass and glass tempered from a molten state. Hardened glass in the solid state has a slightly higher coefficient of expansion than annealed glass, and their microhardness and density also differ sharply.

MSA casting alloys show that in the concentration range of 0-65 mol % Tl2S3 samples are glassy. As a result, in the mode of quenching into liquid nitrogen, all alloys of the system are obtained in a glassy form. MCA

annealed alloys shows that in addition to alloys containing 0-3.5 and 50 mol % Tl2S3 are single-phase, the other alloys are two-phase.

Tab. 1.

Composition, DTA results, microhardness measurements and density determination of alloys of the _ As2Se3-Tl2S3 system before annealing (glassy)_

Composition, mol % Thermal effects, °C Density, 103 kt/M3 Microhardness, MPa

As2Se3 Tl2S3 a Tl2As2S3Se3 Tl2S3

P=0,15 H P=0,10 H

100 0.0 185,380 4,62 1300 - -

97 3,0 180.370 4,70 1370 - -

95 5,0 180,310,365 4,76 1380 - -

90 10 175,250,355 4,92 1340 - -

85 15 170.220.340 5,07 1390

80 20 165.220,315 5,23 1390 - -

70 30 60.220.275 5,51 1390 - -

60 40 150.220 5,70 - - -

55 45 145,220,255 5,85 - 1170 -

50 50 140.275 5,95 - 1170 -

45 55 140.80.270.160 6,25 - 1150 -

40 60 130,80,160.260 6,42 - 1160 -

30 70 130.80.160.220 6,70 - 1150 -

20 80 130.80.150,170 7,00 - - -

12 88 130.80,195 7,17 - - -

10 90 80.90.205 7,32 - - 610

5,0 95 80.95.220 7,40 - - 610

3,0 97 80.95.225 7,50 - - 600

0.0 100 100,230 7,60 - - 580

Tab. 1.

Composition, DTA results, microhardness measurements and density determination of alloys of the

As2Se3-Tl2S3 system after annealing ^ (crystalline)

Composition, mol % Thermal effects, °C Density, 103 kt/m3 Microhardness, MPa

As2Se3 Tl2S3 a Tl2As2S3Se3 Tl2S3

P=0,15 H P=0,10 H

100 0.0 380 5,10 1300 - -

97 3,0 370 5,17 1370 - -

95 5,0 310,365 5,20 1380 - -

90 10 250,355 5,30 1340 - -

85 15 220.340 5,38 1390 -

80 20 220,315 5,50 1390 - -

70 30 220.275 5,60 1390 - -

60 40 220 5,72 - Эвтек. Эвтек.

55 45 220,255 5,82 - 990 -

50 50 275 6,10 - 970 -

45 55 80.270.160 6,48 - 950 -

40 60 80,160.260 6,62 - 950 -

30 70 80.160.220 6,80 - 950 -

20 80 80.150,170 7,10 - - -

12 88 180,195 7,25 - Эвтек. Эвтек.

10 90 80.90.205 7,32 - - 610

5,0 95 80.95.220 7,40 - - 610

3,0 97 80.95.225 7,52 - - 600

0.0 100 100,230 7,60 - - 580

Three rows of microhardness values were obtained in the system: the first of them corresponds to the microhardness of a-solid solutions based on As2Se3, the second to Tl2Às2S3Se3, and the third to TI2S3.

I,% 1000 800 600 400 200

1% 10 00

8 00 600 400 200

1% 1000

800

600

400

200

Fig. 1

JüJtaJiU-t-,

State diagram of the As2Se3-Tl2S3 system. Glass formation area in the slow cooling mode 1, and in the

quenching mode in liquid nitrogen 2. Rice. 2. Diffractograms of alloys of the As2Se3-Tl2S3 system. 1-As2Se3, 2- Tl2As2S3Se3, Tl2S3.

As can be seen from Table. 1.2, the values of microhardness of alloys from the region of glasses before and after annealing differ. For glasses based on As2Se3 before annealing, the microhardness varies within (1300-1390) MPa, and for Tl2As2SsSe3 glasses, within (1150-1170) MPa. After annealing, for As2Se3 glasses Нц=(760-820) MPa, and for TbAfcSsSes glasses Нц=(950-990) MPa.

On the basis of DTA, XRD, MCA, a state diagram of the As2Se3-Tl2S3 system was constructed (Fig. 1). The state diagram of the As2Se3-Tl2S3 system is partially quasi-binary. The system is a diagonal section of the ternary reciprocal system As,Tl//S,Se. The cuts As2Se3-Tl2S3 and As2S3-Tl2Se3 intersect at a component ratio of 1:1. A congruent Tl2As2S3Se3 compound is formed at the intersection point. Therefore, both cuts

3

are quasi-binary. The TbAs2S3Se3 compound is obtained in a glassy form and melts at 548 K, the glass transition temperature is Tg=413 K.

To confirm the TbAs2S3Se3 compound, DTA, MSA, XRD, as well as microhardness measurements and density determinations before and after annealing were carried out. The XPA data (Fig. 2) showed that the X-ray diffraction pattern of the alloy with a composition of 50 mol. % Tl2S3, reflections are observed that are not associated with the initial components, which makes it possible to attribute these reflections to the new Tl2As2S3Se3 phase.

As a result of X-ray diffraction analysis, it was found that the TbAs2S3Se3 compound crystallizes in the hexagonal system with lattice parameters: a=10.69 A; c=9.54 A, z=4, Ppyc=5.95 103 kg/m3, px-ray=5.98T03 kg/m3. Crystallographic data of the compound are given in table. 3.

The liquidus of the As2Se3-Tl2S3 system consists of three branches of primary crystallization: a-phase (solid solutions based on As2Se3), TbAs2S3Se3 and TlS. a-phases and the TbAs2S3Se3 compound form a eutec-tic with a composition of 40 mol % ThS3 at a melting point of493 K. In the concentration range of 3.5-50 mol % Tl2S3 below the solidus line, the alloys of the system are a mixture of two phases a + TbAs2S3Se3. Part of the state diagram of the TbAs2S3Se3 - TI2S3 system is partially quasi-binary.

In this region, eutectic equilibrium and peritectic transformation take place. The Tl2S3 compound melts incongruently at 373 K. Above a temperature of 373 K, the Tl2S3 compound decomposes according to the reaction: Tl2S3^L + TlS. Consequently, three-phase alloys L+ Tl2As2S3Se3+ H2S3 and L+ TlS + H2S3 exist above the solidus line.

Below the solidus line, the reverse reaction occurs, i.e., a peritectic reaction occurs: W+TlS.-^-ThS3. Therefore, two-phase Tl2As2S3Se3+Tl2S3 alloys crystallize below the solidus line. Thus, the state diagram of the As2Se3-Tl2S3 system is presented as a stable section of the ternary reciprocal system As,Tl//S,Se.

Conclusion

Thus, the state diagram of the As2Se3-TbS3 system has been constructed. The nature of the interaction of the components is identical with the As2Se3-TbS3 system; they are diagonal sections of the As,Tl//S,Se ternary mutual system. One chemical compound Tl2As2S3Se3 is formed in the system, which melts con-gruently at 548 K. X-ray indexing revealed that the Tl2As2S3Se3 compound crystallizes in the hexagonal syngony with lattice parameters: a=10.69 A; c=9.54 A, z=4, Ppyc/=5.95 103 kg/m3, px-ray=5.98 103 kg/m3. It has been established that solid solutions based on As2Se3 extend up to 3.5 mol % TbS3, and solid solutions based on Tl2S3 are practically not found.

The As2Se3-Tl2S3 system has extensive areas of glass formation. It was found that in the mode of slow cooling, the glass-forming regions reach 65 mol. % Tl2S3, and in the mode of quenching in liquid nitrogen, all alloys are obtained in a glassy form.

REFERENCES:

1. Lovu M., Shutov S., Rebeja S., Colomeyco E., Popescu M. Effect of metal additives on photodarken-ing kinetics in amorphous As2Se3 films // Journal of Optoelectronics and Advanced Materials 2000. V. 2, Issue: 1. P 53-58.

2. Кириленко В.В., Дембовский С.А., Поляков Ю.А. Оптические свойства стекол в системах As2S3-TlS и As2Se3-TlSe // Известия АН СССР. Неорганические материалы, 1975, т.11, №11, с.1923-1928.

3. Алиев И.И., Бабанлы М.Б., Фарзалиев А.А. Оптические и фотоэлектрические свойства тонких пленок стекол (As2Sез)l-х(TlSе)х (х=0,05-0,10) // XI Международная конференция по физике и технологии тонких пленок. Иваново-Франковск, Украина, 7-12 мая, 2007, с. 86.

4. Hari P., Cheneya C., Luepkea G., Singha S., Tolka N., Sanghera J.S., Aggarwal D.. Wavelength selective materials modification of bulk As2S3 and As2Se3 by free electron laser irradiation // Journal of Non-Crystalline Solids 270 (2000) . p.265-268.

5. Hineva Т., Petkova T.,Popov С., Pektov P.. Reithmaier J. P., Funrmann-Lieker T., Axente E.. Sima F.. Mihailescu C. N., Socol G., Mihailescu I. N. Optical study of thin (As2Se3)1-x(AgI)x films // Journal of op-toelektronics and Advanced Materials. 2007.V. 9. No. 2. February. P. 326 - 329.

6. Andriesh A.M., Verlan V. I.. Donor- and acceptor-like center revealing by Photoconduktivity of amorphous thin As2Se3 films // Journal of Optoelectronic and Advanced Materials 2001. V. 3. No. 2, June. P. 455 - 458.

7. Bhawana Dabas and R. K. Sinha Dispersion Properties of Chalcogenide As2Se3 Glass Photonic Crystal Fiber // ICOP 2009-International Conference on Optics and Photonics Chandigarh, India, 30 Oct.-1 Nov.2009. P. 123-127.

8. Slusher R.E., Lenz G., Hodelin J., Sanghera J., Shaw L.B., and Aggarwal I.D. Large Raman gain and nonlinear phase shifts in high-purity As2Se3 Chalco-genide fibers // J. Opt. Soc. Am. 2004. B. 21. P. 11461155.

9. Seema Kandpal, Kushwaha R. P. S.. Photoa-coustic spectroscopy of thin films of As2S3, As2Se3 and GeSe2 // Indian Academy of Sciences. PRAM ANA journal of physics. 2007. V. 69. No. 3. P. 481-484.

10. Бабаев А. А., Мурадов Р., Султанов С. Б., Асхабов А. М.. Влияние условий получения на оптические и фотолюминесцентные свойства стеклообразных As2S3 // Неорган. материалы. 2008. №11. Т.44. С. 1187-1201.

11. Fu L.B., Rochette M., Ta'eed V., Moss D., and Eggleton B.J., Investigation of self-phase modulation based optical regeneration in single mode As2Se3 Chal-cogenide glass fiber // Opt. Express 2005. V.13. P. 7637-7642.

12. Jackson S.D. and Anzueto-Sanchez G. Chal-cogenide glass Raman fiber laser // Appl. Phys. Lett., 2006. V.88. P. 221106.

13. Fu L.B., Fuerbach A., Littler I.C.M., and Eggleton B.J. Efficient optical pulse compression using

Chalcogenide single-mode fibers // Appl. Phys. Lett. 2006. V.88. P. 081116.

14. Джафаров Я.И., Бабанлы М.Б. Квазитройная система Tl2S-Sb2S3-Bi2S2 // Журн. Неорганической химии. 2009. Т. 54. №11. С. 1920-1924.

15. Велиев Дж.А., Алиев И.И., Мамедова А.З. Фазовое равновесие в системе As2S3-TlSe // Журн. неорган. химии. 2007. Т.52. № 2. С. 312-315.

16. Фарзалиев А.А., Алиев И.И., Алиев О.М., Алиев И.Г. Фазообразование в системе As2Se3-TlSe // Химические Проблемы. 2006. № 2. С. 284-287.

17. Заргарова М.И., Мамедов А.Н., Аждарова Дж.С., Ахмедова (Велиев) Дж.А., Абилов Ч.И. Справочник: Неорганические вещества, синтезированные и исследованные в Азербайджане. Баку. Изд. Элм. 2004. 462 с.

18. Кириленко В.В., Дембовский С.А., Поляков Ю.А. Оптические свойства стекол в системах As2S3-TlS и As2Se3-TlSe // Известия АН СССР. Неорганические материалы. 1975. T.11. №11. C. 19231928.

19. Кириленко В.В., Никитин В.К., Дембов-ский С.А. Стеклообразование и особенности хими-

ческого взаимодействия в халькогенидных системах As2X3-TbX // Известия АН СССР. Неорганические материалы. 1975. T.11. №11. C. 1929-1935.

20. Кириленко В.В., Дембовский С.А., Поляков Ю.А. Оптические свойства стекол в системах As2S3-TlS и As2Se3-TlSe // Известия АН СССР. Неорганические материалы. 1975. T.11. №11. C. 19231928.

21. Андриеги А.М., Коломиец Б.Т. Электропроводность и термо-эдс стеклообразных полупроводников в системе TbSe-As2(Se,Te)3 // ФТТ. 1964. T. 6. № 4. C. 3317-3320.

22. Катилене Е.Р., Регель А.Р. Электропроводность теллурида таллия в твердом и жидком состояниях // ФТТ. 1964. T. 6. № 9. C. 2869-2872.

23. Alexander K Fedotov, M.I.Tarasik, T. G. Mammadov, Ivan Svito et.al. Elektrical properties of the layered single crystals TlGaSe2 and TlInS2 // Prze-glad Elektrotechniczny. 2012. V. 88(7a). P. 301-304.

24. Panich A.M. Electronic properties and phase transitions in low-dimensional semiconductors //Jour-nal of Physics: Condensed Matter. 2008. V.20. P. 20331.