  Background: Semiconductor-doped glasses are treated actively through many
years and continue to be of great interest because challenged features of
nanosized semiconductors of various chemical nature. Copper chalcogenides have
discovered the plasmonic properties in line with quantum confinement effects
specific for major of semiconductor nanoparticles. Objective: The aim of this
work is to study structural and optical features of the sol-gel derived silica
glasses with copper selenide nanoparticles demonstrating appearance of the
plasmonic light absorption in the near IR range. Method: The samples under
study were fabricated through an original sol-gel technique realizing the
simultaneous synthesis of copper selenide and sintering of mesoporous silica.
The copper selenide glasses were characterized with X-ray diffraction (XRD),
transmission electron microscopy (TEM) and optical absorption spectroscopy.
Results: Formation of nanocrystalline Cu2-xSe particles of the size range from
tens nm through 100-150 nm is established with XRD and TEM techniques. The
principal optical properties are presented by the featured absorption in the
visible and near-IR ranges. Eg was evaluated for the direct transitions in the
range of 2.10-2.36 eV. The plasmonic resonance in the nanoparticles due to
increased carrier concentration originated by intrinsic defectness of Cu2-xSe
nanoparticles with variable stoichiometry. Its energy can be controlled by
Cu/Se ratio in the synthesis procedure.
