Theoretical And Applied Investigation Of PL Characteristics For Yb: Er Co-doped Materials

Trivalence ion of the rare element erbium is of considerable application potential in many fields, such as optical amplifier, laser, color display and temperature sensor, and so on. It is significant to investigate preparation and luminescence mechanism of Er-doped materials experimentally and theoretically.Firstly, Yb:Er co-doped Al2O3 films were prepared on the SiO2/Si substrate by the medium frequency magnetron sputtering. The influence of the technical parameters, including sputtering time, sample bias voltage and annealing, on surface topography and photoluminescence characteristics of Yb:Er:Al2O3 films was discussed. The results show that Yb, Er grains distribute uniformly, full width at half maximum of PL spectra and power spectra are also different when the films were prepared at different conditions. The optimal parameters are 120 minutes sputtering, 200V bias voltage and 2h, 900℃annealing.Secondly, rate equations of eight energy levels for Yb:Er co-doped Al2O3 film, and nine energy levels for Yb:Er co-doped silicate glass were founded, respectively, under considering two cooperative up-conversions, cross-relaxation and excited state absorption. The values of above coefficients were thought phenomenistically to change as a function of the concentration of ytterbium, erbium and their dopant ratio. The relationship between 1530nm photoluminescence intensity and dopant concentration, pump power for Yb:Er co-doped Al2O3 film, or between 1530nm, 664nm, 549nm photoluminescence intensity and dopant concentration, pump power for Yb:Er co-doped silicate glass were simulated numerically. The results show that for Yb/Er co-doped Al2O3 films, when Er concentration and pump power are fixed, there is the optimal Yb concentration; when Er concentration is fixed, the optimal Yb:Er ratio decreased with pump power increasing; when pump power is fixed, the optimal Yb:Er ratio decreased follow with Er concentration increased. Similarly, for Yb:Er co-doped silicate glass, when the Er3+ concentration is fixed, there is the optimal Yb3+ concentration for 1530nm, but the red emission intensity and the green emission intensity are always increasing. When the Yb3+ concentration is fixed, three kinds of photo- luminescence intensity is increasing. If Er3+ concentration and Yb3+ concentration are all fixed, three kinds of fluorescent intensity always increase at the same time.In the third place, the preparation of Er and Yb:Er co-doped silicate glass samples are presented, and the principle of optical temperature sensor based on the fluorescence intensity ratio were introduced. The relationship between the intensity ratio of 534 and 549nm, sensitivity, and absolute temperature was measured in the temperature range of 296-673K pumped by 980nm laser semiconductor for two glass samples.At last, future research direction has been prospected for erbium- doped materials.