Thermal plasma synthesis and optical properties of Zn2SnO4 nanopowders

In this research, we used the DC thermal plasma technique to produce well-crystallized zinc stannate (Zn2SnO4) nanopowders from commercial Zn–Sn alloy wire. The as-synthesized Zn2SnO4 consisted of spherical, rhombohedral and hexagonal shapes with an average size of about 35 nm. The room-temperature photoluminescence spectroscopy of the Zn2SnO4 showed a UV emission at 390 nm and visible emissions at 577, 651 and 671 nm. The UV emission was assigned to the near band-edge emission while the visible emissions were believed to be attributed by the residual strain, the crystal defects, the oxygen vacancies and the interstitial Zn during the growth process of ZTO2. According to UV–vis spectrum, the absorption edge of Zn2SnO4 is 367 ± 5 nm, which corresponds to the band gap energy of 3.36 ± 0.06 eV.