Abstract
Atomically thin boron nitride (BN) film has attracted increasing attention among two-dimensional materials for the potential application in electronics devices. The thermal properties of few-layer BN nanosheets (∼2.27 nm) on SiO2/Si substrates have been investigated without and with high-k Al2O3 capping layer, using the temperature-dependent and polarized-laser power-dependent Raman spectroscopy measurements. Due to the effect of Al2O3 capping layer, Raman spectrum illustrates the blue-shift of frequency from 1364.9 cm−1 to 1367.9 cm−1, and the first order temperature coefficient for E2g mode of BN layers increases from −0.02243 cm−1/K to −0.06544 cm−1/K. Furthermore, the room-temperature thermal conductivity of BN with Al2O3 capping layer is found to be 332.57 W/mK, which is much larger than that of BN without Al2O3 capping layer (∼94.51 W/mK). The enhancement is attributed to the interface charges and compressive stress at the interface between BN and Al2O3 capping layer, which has been clarified by the first principle calculations. This work is aimed at expanding the applications of BN materials and improving the performances of BN-based devices in thermal properties.
Published Version
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