Characterization of hexagonal boron nitride layers on nickel surfaces by low-energy electron microscopy

TL;DR

This study uses low-energy electron microscopy to analyze the thickness and interface structure of hexagonal boron nitride layers grown on nickel, providing insights into their electronic interactions and surface orientation effects.

Contribution

It introduces a combined experimental and theoretical approach to determine hBN layer thickness and interface geometry on nickel surfaces using LEEM and electronic structure simulations.

Findings

Identified distinct reflectivity minima and maxima related to hBN layers.

Deduced the number of hBN layers and their separation from nickel.

Explored the coupling of interlayer states with nickel surface states.

Abstract

The thickness and interfacial geometry of hexagonal boron nitride (hBN) films grown by chemical vapor deposition on polycrystalline nickel foils is studied using low-energy electron microscopy (LEEM). The reflectivity of the electrons, measured over an energy range of 0 - 20 eV, reveals distinct minima and maxima. The measured data is compared with simulations based on a first-principles description of the electronic structure of the material. From this comparison, the number of hBN layers and the separation between the lowest hBN layer and the nickel surface is deduced. The coupling of interlayer states of the hBN to both image-potential and Shockley-type surface states of the nickel is discussed, and the dependence of the reflectivity spectra on the surface orientation of nickel grains is examined.