Superior thermal conductivity in suspended bilayer hexagonal boron nitride

TL;DR

This study measures the high thermal conductivity of suspended bilayer hexagonal boron nitride, revealing it exceeds bulk values and depends on thickness, using high-quality samples fabricated by a dry-transfer method.

Contribution

It provides the first experimental measurement of thermal conductivity in suspended bilayer h-BN with improved sample quality.

Findings

Thermal conductivity of bilayer h-BN is around 484 W/m·K at room temperature.

Suspended bilayer h-BN exhibits higher thermal conductivity than bulk h-BN.

Thermal conductivity depends on the thickness of the h-BN layers.

Abstract

We reported the basal-plane thermal conductivity in exfoliated bilayer hexagonal boron nitride h-BN that was measured using suspended prepatterned microstructures. The h-BN sample suitable for thermal measurements was fabricated by dry-transfer method, whose sample quality, due to less polymer residues on surfaces, is believed to be superior to that of PMMA-mediated samples. The measured room temperature thermal conductivity is around 484 Wm-1K-1(+141 Wm-1K-1/ -24 Wm-1K-1) which exceeds that in bulk h-BN, providing experimental observation of the thickness-dependent thermal conductivity in suspended few-layer h-BN.