Luminescence and Nanopores in Spinel ZnGa2O4 Ceramics Doped with Mn2+ Ions: Synthesis and Properties of Nanomaterials

The polycrystalline zinc gallate ZnGa
₂
O
₄
samples doped with Mn
²
+ ions have been synthesized via high-temperature solid-state reaction ceramic technique. The obtained ceramics have been characterized employing the methods of xray diffraction analysis, transmission electron microscopy, transition electron diffractometry, energy-dispersive X-ray spectroscopy, positron annihilation lifetime spectroscopy and optical-luminescent spectroscopy. The XRD and TEM diffraction analyses testified in a favor of the successful formation of spinel structure in the prepared samples. The grains of irregular shape were identified with TEM technique. The band gap of ZnGa
₂
O
₄
: Mn
²⁺
spinel was estimated from optical absorption spectra in UV-Vis range. The characteristic bands related to electronic transitions of fundamental absorption edge and Mn
²⁺
ions were found in optical absorption and excitation spectra. The photoluminescence emission spectra exhibited matrix luminescence along with emission band of Mn
²⁺
ions in blue and green spectral region, respectively. The positron annihilation lifetime spectroscopy shows an intense reduction of positron trapping rate deeply in ceramics grains.