Synthesis and characterization of Zn xMg 1 − xGa 2O 4:Co 2+ fabricated by low-temperature burning method

Abstract

A series of Zn x Mg 1 − x Ga 2O 4:Co 2+ spinels ( x = 0, 0.25, 0.5, 0.75, and 1.0) was successfully produced through low-temperature burning method by using Mg(NO 3) 2·4H 2O, Zn(NO 3) 2·6H 2O, Ga(NO 3) 3·6H 2O, CO(NH 2) 2, NH 4NO 3, and Co(NO 3) 2·6H 2O as raw materials. The product was characterized by X-ray diffraction, transmission electron microscopy, and photoluminescence spectroscopy. The product was not merely a simple mixture of MgGa 2O 4 and ZnGa 2O 4; rather, it formed a solid solution. The lattice constant of Zn x Mg 1 − x Ga 2O 4:Co 2+ (0 ≤ x ≤ 1.0) crystals has a good linear relationship with the doping density, x. The synthesized products have high crystallinities with neat arrays. Based on an analysis of the form and position of the emission spectrum, the strong emission peak around the visible region (670 nm) can be attributed to the energy level transition [ 4T 1( 4P) → 4A 2( 4F)] of Co 2+ in the tetrahedron. The weak emission peak in the near-infrared region can be attributed to the energy level transition [ 4T 1( 4P) → 4T 2( 4F)] of Co 2+ in the tetrahedron.