Front Matter

To everyone who pursues research in materials science.

This treatise on Advanced Analytical Techniques for Characterization of 2D Materials is nothing but a tough grind by the many experts who compiled the chapters and have gone through a lot of backbreaking assignments. We are obligated and thankful to the anonymous reviewers who not only appraised the work thoroughly but also enhanced its quality. The immense support from the AIP Publishing team, especially Martine Felton, Claire Gordon, and Dr. Benjamin Johnson, was instrumental and significant. The editors are most grateful to the love of their families, friends, and, above all, the grace from above.

We would like to acknowledge freepik.com for the cover page illustration.

Marie Curie precisely articulated “Have no fear of perfection, you will never reach it.” This quote always acts as a stimulus to scientists and researchers to bend over backwards for uplifting the standard of research and development over the years. The consideration of nanomaterials over their bulk counterparts has not only opened the gates of endless opportunity but also diminished the struggle for real time application. In this context, two-dimensional layered materials have gained tremendous attention in recent years owing to their great promise in the 21st century solid state device technology. After the discovery of graphene, other graphene analogous 2D nanomaterials with novel tunable properties associated with their metallic, semimetallic, semiconducting, insulating, superconducting, Mott-insulating nature, etc., are being explored. The tunable properties, flexibility, good mechanical properties, high packing densities, etc., make them suitable candidate for the development of different thin, flexible, and wearable devices. Transition metal dichalcogenides (TMDs) are one class of 2D materials and are being investigated extensively due to their versatile and interesting properties. They own lamellar crystal structure, where each MX₂ layer is composed of one layer on transition metal atoms M (Mo, W, V, Sn, Nb, Ta, Ti, etc.) sandwiched between two layers of chalcogen atoms X (S, Se, Te) with covalent bonds. The neighboring MX₂ layers are weakly coupled together by van der Waals interactions. Nanomaterials with one atom thickness and infinite lateral size are the ideal 2D material that holds the novel properties associated with it due to their quantum confinement effect. Hence, the characterization of these 2D materials is the first step to investigate their layer-dependent changes in their properties and to use them in different multitude applications. Since the number of layers, the size of the flakes, crystallinity, the presence of defects and vacancies, or adsorbed molecules significantly affect these material properties, advanced analytical techniques are essential to address its morphological and functional properties.

Depending on the requirement, various characterization techniques, such as optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) have been widely used to characterize the 2D materials. Each technique has its own advantages and limitations. Therefore, combining different characterization techniques is highly desirable to understand different structural features and properties of the as-synthesized 2D materials. Furthermore, different operando spectroscopic techniques such as Raman spectroscopy, UV-Vis, XRD, and XPS are being used to understand the mechanism involved in the growth process and device performance of the 2D materials by in situ experimental investigations. The probe based analytical techniques such as AFM and STM can provide the information on the orientation, smoothness, the number of layers, grain size, depth profile, and dielectric and mechanical properties of the 2D materials. Electron diffraction-based techniques such as TEM, SEM, and EDS are useful for determining thickness, number of layers, high-resolution imaging, surface properties, composition, and morphology. X-ray diffraction (XRD), x-ray fluorescence (XRF), x-ray absorption fine-structure (XAFS), and x-ray photoelectron spectroscopy (XPS) deliver rapid qualitative as well as quantitative determination of a wide variety of 2D materials. Similarly, spectroscopy-based analytical tools such as Raman spectroscopy, UV-Vis, and zeta potential analyzer are useful to determine the composition, quality, bandgap, doping, surface charge, thickness, the number of layers, orientation, chemical bonding, etc. By considering these aspects, in this book, we aim to provide detailed information on these analytical techniques, their importance, and recent progress, which have been widely used to characterize different 2D nanomaterials. This book will be useful for the researchers and scientists in the areas of materials science and engineering. Furthermore, this book will serve as a textbook for both beginners and experienced researchers who are pursuing their research in 2D layered materials and their advanced applications.

Professor Chandra Sekhar Rout

Email: r.chandrasekhar@jainuniversity.ac.in; csrout@gmail.com

Professor Dattatray J. Late

Email: datta099@gmail.com

Levna Chacko

Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, Karnataka 560029, India

Shobhnath P. Gupta

National Centre for Nanosciences and Nanotechnology, University of Mumbai, Mumbai 400098, India

Sayed M. Hasnain

National Centre for Nanosciences and Nanotechnology, University of Mumbai, Mumbai 400098, India

Rajesh Jaiswar

National Centre for Nanosciences and Nanotechnology, University of Mumbai, Mumbai 400098, India

Namsheer K

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Riddhi Kadrekar

Amity School of Applied Science, Amity University Maharashtra, Mumbai and Centre for Nanoscience and Nanotechnology, Amity University Maharashtra, Mumbai-Pune Expressway, Bhatan, Post—Somathne, Panvel, Mumbai, Maharashtra 410206, India

Dattatray J. Late

Centre for Nanoscience and Nanotechnology, Amity University Maharashtra, Mumbai 410206, India

Abhinandan Patra

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Sithara Radhakrishnan

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

S. Reshmi

Institute of Physics, Bhubaneswar, Sachivalaya Marg, Gajapati Nagar, Bhubaneswar, Odisha 751005, India

Chandra Sekhar Rout

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Rutuparna Samal

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Aditya Sharma

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Pratik V. Shinde

Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Ramanagaram, Bangalore 562112, India

Vitthal M. Shinde

Department of Chemistry, Annasaheb Waghire College, Otur Post, Junnar Taluka, Pune District, Pune 412409, India

R. Sundheep

Department of Chemistry, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, South Korea

Pravin S. Walke

National Centre for Nanosciences and Nanotechnology, University of Mumbai, Mumbai 400098, India