Study On Preparation,Characterization And Properties Of Yb,Ho:GGG Crystal Material

In this thesis, pure gallium gadolinium garnet (GGG) crystal materials codoped with Yb3+ and Ho3+ were prepared via sol-gel low temperature combustion method and co-precipitation method (ammonia and urea as the precipitants). The effect of pH and the amount of citric acid on the synthesis of powders were discussed. The structure, morphology and fluorescence property of the samples were characterized by X-ray diffractiometer (XRD), infrared spectrometer (IR), scanning electron microscope (SEM), thermogravimetry-differential scanning calorimeter (TG-DSC) and fluorescence spectroscopy. The GGG precursors were prepared by sol-gel low temperature combustion and co-precipitation method. After the calcination at 900℃for 4 h, the results of XRD indicate that the pure-phase GGG powders were obtained; IR spectras show that the the intensity of absorption band water and nitrate decreased or disappeared, instead, new absorption band appeared in spectra. SEM images of samples show that the particle sizes of powders were different by two preparetion methods. By sol-gel low temperature combustion method, the powder particle was approximately spherical with around 30nm in diameter. By co-precipitation method, the particle size of powder was about 55 nm with the use of ammonia; the particle size was about 20 nm with urea. TG-DSC analyses reveal that the weight of precursors was changed along with temperature ascension. At the same time, the crystalline pattern of GGG transformation temperature was 840℃. The fluorescence spectras show that the strongest fluorescence emission peak was 1200nm.