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During the epitaxial growth process of diamond heat sinks, nitrogen impurities are usually unintentionally introduced, which impact on the thermal conductivity. Therefore, the effect of nitrogen doping on the thermal conductivity of diamond heat sink is studied in this paper. The change of thermal conductivity conforms to the K = CT−1+A(B1/T)T5/2, which is attributed to the synergistic effects of phonons and carriers. With the increase of the nitrogen concentration, the downward trend of thermal conductivity gradually flattened and began to show a weak upward trend. This phenomenon is attributed to the anharmonic effect of lattice vibration rather than an increase in the number of conduction electrons. [ABSTRACT FROM AUTHOR]

Diamond has the advantages of excellent thermal conductivity, and it is the material with the largest thermal conductivity currently known, which makes it the ideal heat sink. However, in the process of processing or as a heat sink for electronic devices, diamond is often exposed to a high-frequency, high-voltage, high-temperature, and high-energy environment, which has greatly affected the performance of diamonds. Therefore, in this paper, it systematically explores the influence of near threshold energy electron irradiation and annealing at different temperatures on the thermal conductivity of IIa diamond by the method of laser excited Raman spectroscopy. The results show that before 900 °C annealing, the main factor affecting thermal conductivity in IIa diamond is the large number of vacancy defects caused by near threshold energy electron irradiation. The irradiation and annealing both affect the thermal conductivity by controlling the vacancy defects concentration. [ABSTRACT FROM AUTHOR]

The thermal conductivity of IIa diamond from low temperature (80 K) to room temperature was studied by laser-excited Raman spectroscopy. The laser has two complementary effects, one performing the Raman spectrum and the other resulting in the local heating on the surface of diamond. With the increase in measurement temperature on the surface of IIa diamond, the Raman peak shifts to the low energy side together with intensity quenching due to the strong electron–phonon coupling and lattice expansion, and the thermal conductivity of IIa diamond decreases as T−1, which is attributed to the creation and the annihilation of phonons. [ABSTRACT FROM AUTHOR]