Structure and Luminescence Properties in Tb3+ and Pr3+ Doped AlN Films

Wide bandgap semiconductors, such as AlN, can effectively suppress the temperature quenching effect and expand the spectral range due to their large band gap width. Through the doping of rare earth ions, it is hoped that the excellent optical and magnetic properties of rare earth ions and the good electrical properties of AlN can be integrated. Single-doped and co-doped wide-bandgap materials with different rare earth ions have bright application prospects and high commercial value in many fields such as photoelectric detection and lighting display. Doped rare earth ions usually form a variety of light-emitting centers under the action of defects, and the properties of different light-emitting centers are different, and the complex defect environment also plays an important role in the luminescence of rare earth ions. However, the luminescence intensity of rare earth ions doped with nitride needs to be improved, and the interaction of rare earth ions after co-doping is not clear. In this study, ion implantation was employed to co-dope Tb3+ and Pr3+ into AlN thin films grown on sapphire by metal-organic chemical vapor deposition method and annealed at 1 000 degrees C under normal pressure for 2 h under NH3 atmosphere. During ion implantation, the beam is tilted approximately 10 degrees relative to the normal of the AlN thin film (0002) surface, and the accelerating voltage is 200 keV. In order to characterize the stress changes of the annealed samples with different injection doses, HRXRD and Raman spectroscopy were performed on the samples. Its luminescence performance was measured by a Mono CL3+ cathode fluorescence spectrometer mounted on a Quanta400FEG field emission scanning electron microscope. The influence of varying Pr3+ doses on the structural integrity and luminescence behavior of the samples was systematically investigated. The sample and parabolic mirror remain in the same position throughout the test. The height of the parabolic mirror and the working distance during the test also remain constant. The instrument's acceleration voltage, spot size, aperture size, and integration time are all consistent. All tests were performed at room temperature. Results indicate that, under a constant Tb3+ doses, the introduction of Pr3+ ions increases internal lattice stress. As the doses of Pr3+ increases, due to the cumulative effect, stacking faults or large clusters will be formed in the cascade, making the stacking network denser, and the point defects are easier to pass through the network, and the excess vacancies reaching the surface layer will cause the ion implantation area of the surface layer to shrink, thereby releasing the compressive stress to a certain extent. CL spectroscopy reveals divergent trends in the emission intensities of Tb3+ and Pr3+ with increasing Pr3+ doses. The interaction between Tb3+ and Pr3+ were investigated. It was found that there may be exit energy transfer pathway from Tb3+ and Pr3+in AlN, and the method that regulated the luminescence chromaticity by adjusting the ratio of Tb3+ and Pr3+ was proved. Further analysis suggests the occurrence of resonant energy transfer from Tb3+ to Pr3+ , described by the transition 5D4[Tb3+ ]+3H5[Pr3+ ]-> 7 F5[Tb3+ ]+3 P1[Pr3+ ]. CIE software coordinates the luminescent colors in the material to form chromaticity coordinates. Color temperature indicates the temperature at which black will be heated to the desired color, measured in Kelvin. As the Pr3+ doses increases, the chromaticity coordinate shifts from (0.268 2, 0.305 0) to (0.293 7, 0. 320 7), with the emission color transitioning from blue-green to yellow-green and the color temperature rising from 7 336 K to 10 260 K. This thesis shows that it is feasible to obtain light emission through Tb3+ and Pr3+ doped AlN, especially the energy transfer between Tb3+ and Pr3+ provides a new idea for the development of novel nitride photoelectric materials.