Fig. 6From: Controlled Hydrothermal Synthesis and Photoluminescence of Nanocrystalline ZnGa2O4:Cr3+ MonospheresXRD patterns of the products obtained after a 6, b 12, c 18, and d 24 h of hydrothermal reaction at 180 °C. The Cit3−/M molar ratio R is 1.0, and the system pH is 5 in each caseBack to article page