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'Cold' crystallization in nanostructurized 80GeSe2-20Ga2Se3 glass.

Klym H, Ingram A, Shpotyuk O, Calvez L, Petracovschi E, Kulyk B, Serkiz R, Szatanik R - Nanoscale Res Lett (2015)

Bottom Line: 'Cold' crystallization in 80GeSe2-20Ga2Se3 chalcogenide glass nanostructurized due to thermal annealing at 380°C for 10, 25, 50, 80, and 100 h are probed with X-ray diffraction, atomic force, and scanning electron microscopy, as well as positron annihilation spectroscopy performed in positron annihilation lifetime and Doppler broadening of annihilation line modes.It is shown that changes in defect-related component in the fit of experimental positron lifetime spectra for nanocrystallized glasses testify in favor of structural fragmentation of larger free-volume entities into smaller ones.Nanocrystallites of Ga2Se3 and/or GeGa4Se8 phases and prevalent GeSe2 phase extracted mainly at the surface of thermally treated samples with preceding nucleation and void agglomeration in the initial stage of annealing are characteristic features of cold crystallization.

View Article: PubMed Central - PubMed

Affiliation: Lviv Polytechnic National University, 12 Bandera str, Lviv, 79013 Ukraine.

ABSTRACT
'Cold' crystallization in 80GeSe2-20Ga2Se3 chalcogenide glass nanostructurized due to thermal annealing at 380°C for 10, 25, 50, 80, and 100 h are probed with X-ray diffraction, atomic force, and scanning electron microscopy, as well as positron annihilation spectroscopy performed in positron annihilation lifetime and Doppler broadening of annihilation line modes. It is shown that changes in defect-related component in the fit of experimental positron lifetime spectra for nanocrystallized glasses testify in favor of structural fragmentation of larger free-volume entities into smaller ones. Nanocrystallites of Ga2Se3 and/or GeGa4Se8 phases and prevalent GeSe2 phase extracted mainly at the surface of thermally treated samples with preceding nucleation and void agglomeration in the initial stage of annealing are characteristic features of cold crystallization.

No MeSH data available.


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AFM images of 80GeSe2-20Ga2Se3glass annealed at 380°C for 25 (a) and 80 (b) h.
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Fig2: AFM images of 80GeSe2-20Ga2Se3glass annealed at 380°C for 25 (a) and 80 (b) h.

Mentions: The maxima associated with GeSe2 phase appear on the XRD patterns of thermally annealed 80GeSe2-20Ga2Se3 glass too [18], but (in contrast to [1]) they cannot be well distinguished as separate crystalline peaks even for prolonged annealing. It means that GeSe2 crystals appear only in a small amount. However, after longer treatment (over 50 h), surface crystallization occurs more efficiently. To better understand these processes, the ChG annealed for 25 and 80 h at 380°C were examined by AFM and SEM. As shown in Figure 2a, crystallization of GeSe2 phase in samples annealed for 25 h begins on a surface. With annealing increased to 80 h, the GeSe2 crystals in form of wires with 1- to 3-μm lengths are non-uniformly distributed on sample surface (see Figures 2b and 3).Figure 2


'Cold' crystallization in nanostructurized 80GeSe2-20Ga2Se3 glass.

Klym H, Ingram A, Shpotyuk O, Calvez L, Petracovschi E, Kulyk B, Serkiz R, Szatanik R - Nanoscale Res Lett (2015)

AFM images of 80GeSe2-20Ga2Se3glass annealed at 380°C for 25 (a) and 80 (b) h.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385280&req=5

Fig2: AFM images of 80GeSe2-20Ga2Se3glass annealed at 380°C for 25 (a) and 80 (b) h.
Mentions: The maxima associated with GeSe2 phase appear on the XRD patterns of thermally annealed 80GeSe2-20Ga2Se3 glass too [18], but (in contrast to [1]) they cannot be well distinguished as separate crystalline peaks even for prolonged annealing. It means that GeSe2 crystals appear only in a small amount. However, after longer treatment (over 50 h), surface crystallization occurs more efficiently. To better understand these processes, the ChG annealed for 25 and 80 h at 380°C were examined by AFM and SEM. As shown in Figure 2a, crystallization of GeSe2 phase in samples annealed for 25 h begins on a surface. With annealing increased to 80 h, the GeSe2 crystals in form of wires with 1- to 3-μm lengths are non-uniformly distributed on sample surface (see Figures 2b and 3).Figure 2

Bottom Line: 'Cold' crystallization in 80GeSe2-20Ga2Se3 chalcogenide glass nanostructurized due to thermal annealing at 380°C for 10, 25, 50, 80, and 100 h are probed with X-ray diffraction, atomic force, and scanning electron microscopy, as well as positron annihilation spectroscopy performed in positron annihilation lifetime and Doppler broadening of annihilation line modes.It is shown that changes in defect-related component in the fit of experimental positron lifetime spectra for nanocrystallized glasses testify in favor of structural fragmentation of larger free-volume entities into smaller ones.Nanocrystallites of Ga2Se3 and/or GeGa4Se8 phases and prevalent GeSe2 phase extracted mainly at the surface of thermally treated samples with preceding nucleation and void agglomeration in the initial stage of annealing are characteristic features of cold crystallization.

View Article: PubMed Central - PubMed

Affiliation: Lviv Polytechnic National University, 12 Bandera str, Lviv, 79013 Ukraine.

ABSTRACT
'Cold' crystallization in 80GeSe2-20Ga2Se3 chalcogenide glass nanostructurized due to thermal annealing at 380°C for 10, 25, 50, 80, and 100 h are probed with X-ray diffraction, atomic force, and scanning electron microscopy, as well as positron annihilation spectroscopy performed in positron annihilation lifetime and Doppler broadening of annihilation line modes. It is shown that changes in defect-related component in the fit of experimental positron lifetime spectra for nanocrystallized glasses testify in favor of structural fragmentation of larger free-volume entities into smaller ones. Nanocrystallites of Ga2Se3 and/or GeGa4Se8 phases and prevalent GeSe2 phase extracted mainly at the surface of thermally treated samples with preceding nucleation and void agglomeration in the initial stage of annealing are characteristic features of cold crystallization.

No MeSH data available.


Related in: MedlinePlus