Photoluminescence of the Mn-doped ZnGa2O4 Phosphors Prepared by Coprecipitation of Metal Salts

Manganese-activated zincgallate (Zn1-xMnxGa2O4) phosphor as a green phosphor was readily prepared by co-precipitation in aqueous basic solution of metal salts. The obtained product converted to amorphous zincgallate even at 300 oC, followed by crystallization at 1000 oC. The pyrolyzed phosphor showed fine particle, then re-duction treatment at 900 oC changed into homogeneous shape with slight grain growth(particle size less than 0.5 µm). The photoluminescence characteristics of the zincgallates have been investigated as a function of dopant concentrations, reducing atmospheres and temperatures. Under UV excitation the phosphors displayed the highest green emission efficiency at 504 nm when the specimen oxidized at 1000 oC was reduced at 900 oC in a mild hydrogen atmosphere (97 % N2, 3%H2) with a flow rate of 100 ml/min