Incorporation of Ga into the structure of Ge-Se glasses

摘要

The structure of Ga-containing Ge-Se glasses is studied by high-resolution X-ray photoelectron and extended X-ray absorption fine-structure spectroscopies. The results show that in Ga_xGe_ySe_(100-x-y) glasses both Ga and Ge atoms are 4-fold coordinated, whereas Se atoms are 2-fold coordinated. For Se-deficit samples with Se content less than 67 at.%, Ge-Ge(Ga) bonds appear. First, Ge-Ge bonds are formed indicating preference for the formation of (Se)_2 > Ga < (Se)_2 units over the regular GeSe_(4/2) tetrahedra. Metal-Ga bonds appear only in the most Se-deficit sample. Addition of Ga facilitates more uniform Se distribution in comparison to binary Ge-Se or ternary As(Sb)-Ge-Se systems. The observed structural features are correlated with some basic thermo-mechanical properties of the investigated glasses.