Giant visible and infrared light attenuation effect in nanostructured narrow-bandgap glasses.

A unique effect of Bi on the optical and electrical properties of mixed Ga-containing Ge-Se and Ge-Te glasses is discovered. It is shown that glass with a low Bi content is completely transparent in a 3-16 μm spectral range, while the glass with a slightly higher Bi content possesses a large (>10  db/mm) attenuation coefficient, making a ∼millimeter thick glass sample fully opaque to VIS-IR radiation. Despite this contrast, both types of glass are found to retain their semiconducting properties, the DC conductivity at room temperature, σ∼10  S/m, being comparable to that of silicon.

Nanoscale Inhomogeneities Mapping in Ga-Modified Arsenic Selenide Glasses.

Nanoscale inhomogeneities mapping in Ga-modified AsSe glass was utilized exploring possibilities of nanoindentation technique using a Berkovitch-type diamond tip. Structural inhomogeneities were detected in Ga(AsSe) alloys with more than 3 at.% of Ga.

Free-Volume Nanostructurization in Ga-Modified As2Se3 Glass.

Different stages of intrinsic nanostructurization related to evolution of free-volume voids, including phase separation, crystalline nuclei precipitation, and growth, were studied in glassy As2Se3 doped with Ga up to 5 at. %, using complementary techniques of positron annihilation lifetime spectroscopy, X-ray powder diffraction, and scanning electron microscopy with energy-dispersive X-ray analysis. Positron lifetime spectra reconstructed in terms of a two-state trapping model testified in favor of a native void structure of g-As2Se3 modified by Ga additions.

Study of Ga incorporation in glassy arsenic selenides by high-resolution XPS and EXAFS.

Effect of Ga addition on the structure of vitreous As2Se3 is studied using high-resolution X-ray photoelectron spectroscopy and extended X-ray absorption fine structure techniques. The "8-N" rule is shown to be violated for Ga atoms and, possibly, for certain number of As atoms. On the contrary, Se keeps its 2-fold coordination according to "8-N" rule in the amorphous phase throughout all the compositions.