First-principles study of thermoelectric properties of blue phosphorene

摘要

Thermoelectric behavior involving coupled electron and phonon transport properties of monolayer blue phosphorene is studied using the Boltzmann transport equation and first-principles calculations based on the density functional perturbation theory and Wannier interpolation. We find that the maximum figure of merit, ZT, of 0.016 is achievable in n-type blue phosphorene at 500K with a positive gate voltage of 0.948 V. The relatively low ZT value is due to the large lattice thermal conductivity, which is around 130 W/mK at 300 K. This large lattice thermal conductivity is attributed to the small three-phonon scattering phase space due to the presence of a large phonon frequency gap in the dispersion. The relatively large power factor coupled with large thermal conductivity suggests that blue phosphorene can be ideal for active cooling applications. Nanostructuring with a characteristic length of 10 nm, which should not impact electron transport, is promising to reduce lattice thermal conductivity significantly and help increase ZT to the order of magnitude of 1. Our findings may offer perspectives on the potential applications of blue phosphorene in nanoelectronics and thermoelectrics. Published by AIP Publishing.