Excitons in Semiconductors

This book explores fundamental and experimental aspects of excitons in semiconductors. It begins with an introduction to crystal lattice, band structure of solids, effective mass theory, and holes. It then explores the binding energy of various excitons and their complexes (such as trions and biexcitons) in different dimensions within the framework of effective mass approximation, discusses the absorption and emission of photons during their creation and recombination processes providing experimental examples in photo-absorption and photoluminescence (PL) spectroscopy. Theoretical foundations for calculating the dielectric function associated with excitons along with the concept of 'exciton-polaritons' are introduced. The book also examines the interaction between excitons and phonons, which is illustrated with experimental findings. Further, it discusses the effects of magnetic field on the energy eigenstates of excitons, and talks about polarization-resolved spectroscopy under magnetic field for identifying excitons and obtaining deeper insight of the excitonic structure as well as the semiconductor band structure. Lastly, it delves into the manybody effects i.e. Bose-Einstein condensation of excitons and excitonic Mott transition, presenting recent experimental findings and potential applications.

Throughout, emphasis is placed on elucidating fundamental concepts while keeping readers abreast of the latest developments in the field. With a focus on experimental methods and data interpretation, the book serves as an invaluable resource for both graduate students and research scholars.

Basics of Crystal Structure, Band Structure and Lattice Vibrations in Solids.- Energy Eigen States of the Excitons.- Absorption of Light by Excitons.- Recombination of Excitons.- Magnetic Aspects of Excitons.- Many-body Effects in Excitons.

After earning his PhD in Physics from Jawaharlal Nehru University (JNU) in New Delhi, India, in 2001, the author pursued several years of postdoctoral research at the Paul Drude Institut für Festkörperelektronik in Berlin, Germany, as a scientist. He also conducted research at the University of Duisburg-Essen, Duisburg, Germany, as an EU Guest Scientist under a Marie Curie Excellence Grant, focusing on epitaxial growth and the optical and magnetic properties of wide band-gap semiconductors. In 2006, he joined the faculty of Physics at the Indian Institute of Technology Bombay (IITB) in Mumbai, India. Presently, he holds the position of professor and department head in the Physics department at the same institute. With approximately 30 years of research experience, his expertise lies in the study of excitons in semiconducting systems of various dimensions, including epitaxial layers, heterojunctions, nanowires, nanoparticles, and 2D semiconductors. He has authored over 120 peer-reviewed research publications in prestigious international journals. Over the course of 18 years of teaching at IITB, he has instructed numerous undergraduate and postgraduate level courses in condensed matter physics, with a focus on semiconductor physics and the physics of semiconductor devices.