High thermal conductivity of bulk GaN single crystal: n accurate experimental determination
A. V. Inyushkin+, A. N. Taldenkov+, D. A. Chernodubov+, V. V. Voronenkov*, Yu. G. Shreter*× 1)
+National Research Center Kurchatov Institute, 123182 Moscow, Russia
*Ioffe Institute, 194021 St. Petersburg, Russia
×Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
Thermal conductivity κ (T) of bulk single crystal GaN having wurtzite
crystal structure has been measured in the direction parallel to the hexagonal
plane at temperatures T between 5 and 410 K. The room temperature value of
thermal conductivity is equal to W m-1 K-1. The κ (T) reaches a
peak of about 3770 W m-1 K-1 at K. The high value of κ(T) at
low temperatures indicates high quality of the sample under study. The
lowest-temperature results can be very satisfactory explained by McCurdy, Maris, and
Elbaum theory of phonon transport in the diffuse boundary scattering regime.
Above the peak, the measured κ (T) decreases steeply even at high
temperatures. The discrepancies between our experimental results and recent
first-principles calculations are discussed.