Temperature dependence of thermal conductivity in isotopically enriched boron phosphide

Boron phosphide (BP) has emerged as a promising heat-spreading material for electronic devices due to its high thermal conductivity, exceptional mechanical strength, and superior chemical and thermal stability. In this study, we experimentally measure the thermal conductivity of isotopically enriched 10BP and 11BP over a temperature range of 100–300 K using time-domain thermoreflectance. At room temperature, the measured thermal conductivities of 10BP and 11BP are 550 and 580 W/m K, respectively. The 10BP exhibits slightly higher thermal conductivity than 11BP across the entire temperature range. This difference is attributed to variations in phonon dispersion and isotope-induced phonon scattering. This study underscores the role of isotope purification in enhancing the thermal transport properties of BP, reinforcing its potential as an effective thermal management material for high-power electronic applications.