Crystal growth, and high thermal conductivity in cubic zinc-blende BAs and BP

The zinc blende cubic BAs and BP, due to their potential ultra-high thermal conductivity (k) calculated through first principle approach, have attracted significant research efforts in the past few years. In order to experimentally verify the predicted high k values, high quality defect-free single crystal growth is needed to eliminate phonon scattering caused by defects such as deficiency, anti-site defects, voids, impurities, twin/grain boundaries. Herein, we have carried out systematical studies to: 1) find out the suitable crystal growth techniques for BAs and BP despite many challenges; 2) investigate the growth mechanism to optimize the crystal growth; and 3) grow large size of BAs and BP crystals up to 1.5 mm size where a high k up to 600 W/m/K is obtained in BP crystals from time-domain thermoreflectance (TDTR) measurements. The obtained k value is much higher than that of well-known AlN (~400 W/m/K), and is only smaller than that of C-based diamond and nanotube/graphene