Tellurium Crystallisation in GeTeSb System

Maamar Belhadji, Hassan Khoussa, Yahia Zanoun, Mohamed Belbachir, Noureddine Hakiki

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DOI: 10.4236/jcpt.2011.13010                

Abstract

Devitrification study of Ge15Te82Sb3 is compared to Ge14Te84.5Sb1.5 amorphous alloys using differential scanning calo-rimetry (DSC) and X-ray diffraction; we show tellurium effect in isothermal crystallization phenomena. The DSC traces of Ge15Te82Sb3 fixed at 413?C show the phase separation in the sample with increasing transition temperatures Tg followed by two crystallization temperatures Tc1 and Tc2. This sample is compared to Ge14Te84.5Sb1.5 which crystallized by two transition temperatures and two crystallization temperatures Tc1 and Tc2. By X. Rays diffraction, we show that this behaviour is due to the presence of two phases in the amorphous sample with composition vitreous change during heating sample, the most important first one corresponds to the tellurium crystallization in the hexagonal form with 1.8 eV activation energy. The second correspond essentially to the crystallization of Te+ GeTe phase with 2.1 eV activation energy.

Keywords

Chalcogenide, DSC, Switching, Kissinger Model, Crystallization Kinetics

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	S. R. Ovshinsky, “The Relationship between Crystal Structure and Performance as 58. Optical Recording,” Journal of Non-Crystalline Solids, Vol. 141, 1992, pp. 200-203. doi:10.1016/S0022-3093(05)80534-4
[2]	M. Belhadji, N. Ziani and M. Mostefa, “Phase Separation and Devitrification Study of GeTeSb,” Chinese Journal of physics, Vol. 43, No. 11, 2005.
[3]	N. Ziani, M. Belhadji, L. Heireche, Z. Bouchaour and M. Belbachir, “Crystallization Kinetics of Ge20Te80 Chal-cogenide Glasses Doped with Sb,” Physica B: Condensed Matter, Vol. 358, No. 1-4, 2005, pp. 132-137. doi:10.1016/j.physb.2004.12.068
[4]	S. Bordas, M. T. Clavaguer-Mora, B. Legendre and C. Hancheng, “Phase Diagram of the Ternary System Ge-Sb-Te: II. The Subternary Ge-GeTe-Sb2Te3-Sb,” The- rmochimica Acta, Vol. 107, 1986, pp. 239-265. doi:10.1016/0040-6031(86)85051-1
[5]	M. A. Hassan and C. A. Hogarth, “A Comparison of the Optical Properties of Glass and of Evaporated Amorphous Thin Films of BaO-TeO2,” Journal of Materials Science, Vol. 24, No. 5, 1989, pp. 1607-1611. doi:10.1007/BF01105679
[6]	S. Asokan, G. Partansarathy and E. S. R. Gopal, “Evi-dence for a New Metastable Crystalline Compound in GeTe,” Journal of Materials Science Letters, Vol. 4, 1985, p. 50.
[7]	J. Colmenero and J. M Barandiaran, “Crystallization of Al23Te77 Glasses,” Journal of Non-Crystalline Solids, Vol. 30, No. 3, 1979, 263. doi:10.1016/0022-3093(79)90165-0
[8]	N. Afify, “Crystallization Kinetics of Overlapping Phases in Se0.6Ge0.2Sb0.2 Chalcogenide Glass,” Journal of Non- Crystalline Solids, Vol. 126, No. 1-2, 1990, pp. 130-140. doi:10.1016/0022-3093(90)91030-U
[9]	S. C. Moss and J. P de Neufville, “Research on the Prop-erties of Amorphous Semiconductors,” Materials Research Bulletin, Vol. 7, No. 5, 1972, pp. 423-441. doi:10.1016/0025-5408(72)90145-6