15-18 March 2021
DESY
Europe/Berlin timezone

Understanding thermal exfoliation of h-BN using in situ X-ray diffraction

17 Mar 2021, 15:35
20m
https://desy.zoom.us/j/98065314980

https://desy.zoom.us/j/98065314980

Oral contribution In situ / in operando studies In situ / in operando studies

Speaker

Zhengyu Yan (University of Manchester)

Description

2D materials are considered as unique class of modern materials. Understanding the mechanisms behind the exfoliation processes enables us to significantly enhance processing potential of 2D materials. In-situ synchrotron X-ray characterization is employed to study the temporal changes of hexagonal-boron nitride (h-BN) while its initial processing from bulk 3D crystalline material towards its 2D counterpart. In situ X-ray powder diffraction (XPDF) experiment is conducted with thermal cycle that heating bulk h-BN up to 1273 K and subsequent cooling. The results show a linear expansion in c-axis direction of h-BN crystals as commonly understanding, however a contraction behaviour in a-axis direction is observed up to around 750 K during heating process, followed by an expansion behaviour when temperature over 750 K. Characterization particularly indicates structural changes of long-range order favourable for exfoliation between the range of 750 K to 950 K. With the consideration of thermal oxidation studies also, a hypothesis of thermal assisted exfoliation with oxygen interstitial and substitution of nitrogen at high temperature is proposed through our studies to drive the exfoliation mechanisms.

Primary authors

Zhengyu Yan (University of Manchester) Amor Abdelkader (Bournemouth University) Wajira Mirihanage (University of Manchester)

Presentation Materials

There are no materials yet.