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Optimization of Thermal Conductivity in Cu Doped AlN Phosphor

Thermal management is one of the major challenges in the development of high powered LEDs. The effects on thermal conductivity of impurity concentration and thickness are studied in Cu doped AlN (AlN:Cu) phosphor in the paper. Density functional perturbation theory (DFPT) and quasi-harmonic approximation (QHA) combined with Debye model are used in the calculation. The results show that thermal conductivity of AlN:Cu is higher than that of Nd doped ytterbium aluminum garnet (YAG:Nd) from 300K up to 1000K thus the temperature of LEDs can be controlled efficiently. Thermal conductivity increases with the rising of thickness while it decreases with the addition of Cu concentration. The influence of Cu concentration on thermal conductivity depends on temperature. The lower the temperature is, the bigger the influence.