Tuning interfacial thermal conductance of GaN/AlN heterogeneous nanowires by constructing core/shell structure.

The ability to tune the interfacial thermal conductance of GaN/AlN heterojunction nanowires with a core/shell structure is shown using molecular dynamics and nonequilibrium Green's functions method. In particular, an increase in the shell thickness leads to a significant improvement of interfacial thermal conductance of GaN/AlN core/shell nanowires. At room temperature (300 K), the interfacial thermal conductance of nanowires with specific core/shell ratio can reach 0.608 nW/K, which is about twice that of GaN/AlN heterojunction nanowires due to the weak phonon scattering and phonon localization. Moreover, changing the core/shell type enables one to vary interfacial thermal conductance relative to that of GaN/AlN heterojunction nanowires. The results of the study provide an important guidance for solving the thermal management problems of GaN-based devices.