Spectroscopic and microscopic characterization of hexagonal boron nitride

The study of hexagonal boron nitride (h-BN) requires the use of several characterization techniques that are central tools for understanding its structure and properties. In this chapter, we describe different spectroscopic and microscopic characterization techniques relevant to h-BN with particular emphasis on the application and scope of the different techniques based on recent cutting-edge research. We begin by discussing few key tools used for studying the structure of h-BN and its defects, including optical and confocal microscopy, X-ray spectroscopy, vibrational spectroscopy, and scanning probe microscopy (SPM). The application of electron microscopic and spectroscopic techniques, including electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), is discussed next. We also describe the characterization of ripples in h-BN using high-resolution TEM, which are a characteristic deformation mode in layered materials. While discussing EELS, we clarify the theoretical model and illustrate a robust experimental analysis technique that can be used to study the near-edge structures of h-BN corresponding to its core K-shell excitations, which is pivotal for understanding the bonding environment in h-BN. Finally, details of nuclear magnetic resonance (NMR) technique and UV-visual spectroscopy with application to h-BN have been elaborated. The principles behind each technique have been explained followed by a description of its applications for h-BN through several representative examples from recent studies.