Structure of Te-rich Te-Ge-X (X = I, Se, Ga) glasses

Pál Jóvári, Ivan Kaban, Bruno Bureau, Allison Wilhelm, Pierre Lucas, Brigitte Beuneu, Dariusz A Zajac
Journal of Physics. Condensed Matter: An Institute of Physics Journal 2010 October 13, 22 (40): 404207
The structure of glassy Te(78)Ge(11)Ga(11), Te(79)Ge(16)Ga(5), Te(70)Ge(20)Se(10) and Te(73)Ge(20)I(7)--promising materials for far infrared applications--was investigated by means of x-ray and neutron diffraction as well as extended x-ray absorption fine structure measurements at various edges. Experimental data sets were fitted simultaneously in the framework of the reverse Monte Carlo simulation technique. Short range order in Te(85)Ge(15) was reinvestigated by fitting a new x-ray diffraction measurement together with available neutron diffraction and extended x-ray absorption fine structure data. It was found that Te(85)Ge(15) consists mostly of GeTe(4) structural units linked together directly or via bridging Te atoms. Te is predominantly twofold coordinated in Te(85)Ge(15), Te(70)Ge(20)Se(10) and Te(73)Ge(20)I(7) while in Te(78)Ge(11)Ga(11) and Te(79)Ge(16)Ga(5) the Te coordination number is significantly higher than 2. The Te-Te bond length is 2.80 ± 0.02 Å in Te(78)Ge(11)Ga(11) while it is as short as 2.70 ± 0.02 Å and 2.73 ± 0.02 Å in Te(73)Ge(20)I(7) and Te(70)Ge(20)Se(10), respectively. Our results show that the strengths of GeTe(4) (GeTe(3)I, GeTe(3)Se) 'units' are very similar in all glasses investigated but the connection between these units depends on the third component. Differences in the Te coordination number suggest that unlike Se or I, Ga does not build into the Ge-Te covalent network. Instead, it forms a covalent bond with the non-bonding p electrons of Te, which results in an increase in the average Te coordination number.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"