PHOTOINDUCED THERMAL-CONDUCTIVITY CHANGES IN ALUMINUM NITRIDE

This study of defects in oxygen-doped aluminum nitride (AlN) shows that the charge state of vacancy-impurity complexes controls the microscopic coupling between these defects and the host lattice, and thus controls the macroscopic thermal conductivity of AlN samples. This picture is supported in an experimental study that optically varies the charge state of these complexes while probing thermal conductivity, where decreases as large as 4% have been observed after exposure to ultraviolet radiation. These results are explained utilizing a simple model for phonon-vacancy scattering as a function of defect charge.