Thermal Conductivity and
Phonon Transport in Suspended
Few-Layer Hexagonal Boron Nitride
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Abstract
The thermal conductivity of suspended few-layer hexagonal
boron
nitride (h-BN) was measured using a microbridge device with built-in
resistance thermometers. Based on the measured thermal resistance
values of 11–12 atomic layer h-BN samples with suspended lengths
ranging between 3 and 7.5 μm, the room-temperature thermal conductivity
of a 11-layer sample was found to be about 360 W m<sup>–1</sup> K<sup>–1</sup>, approaching the basal plane value reported
for bulk h-BN. The presence of a polymer residue layer on the sample
surface was found to decrease the thermal conductivity of a 5-layer
h-BN sample to be about 250 W m<sup>–1</sup> K<sup>–1</sup> at 300 K. Thermal conductivities for both the 5-layer and the 11-layer
samples are suppressed at low temperatures, suggesting increasing
scattering of low frequency phonons in thin h-BN samples by polymer
residue