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

The ability to tune the interfacial thermal conductance of GaN/AlN heterojunction nanowires (NWs) with a core/shell structure is shown using molecular dynamics and non-equilibrium 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 NWs. At room temperature (300 K), the interfacial thermal conductance of NWs with specific core/shell ratio can reach 0.608 nW K -1 , which is about twice that of GaN/AlN heterojunction NWs 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 NWs. The results of the study provide an important guidance for solving the thermal management problems of GaN-based devices.