Dr. Udai P Singh, PhD, is Senior Professor at Kalinga Institute of Industrial Technology, Bhubaneswar, and has more than 25 years of experience in teaching and research. After completing his PhD from Banaras Hindu University, Varanasi (1993), he joined Global Solar Energy (India) Ltd, Gurgaon, to work on the process development and production of CdTe-based thin-film solar cells. During that period, he also got the training at First Solar Inc. USA. In 2000, he joined the Institute of Energy Conversion, University of Delaware, USA, as Limited Time Researcher and worked on the processes development of flexible CIGS based thin-film solar cells. He joined KIIT in December 2002 as a faulty. During his stay at KIIT, he has been invited as Visiting Consultant to Industrial Technological Research Institute (ITRI), Hsinchu, Taiwan in 2008 and 2009. Dr. Singh has carried out several research project funded by different Govt. of India funding agency. He has nearly 100 papers in peer reviewed journals.   Dr. Nandu B. Chaure, PhD, is Professor in the Department of Physics, at the Savitribai Phule Pune University (formerly University of Pune). Prior to joining SPPU, Professor Chaure worked as Research Fellow (Scientist) at Sheffield Hallam University, Queen Mary College, University of London, UK, and Trinity College, Dublin, over ten years. Professor Chaure is the recipient of Fellow of Maharashtra Academy of Sciences (2016) and the Indian Chemical Society (2020). He is Editor to the Journal of Materials: Materials in Electronics, Springer Publisher. He has secured one International and five Great Britain patents and published more than 150 original peer reviewed research articles in many international journals on the subject dealt with in this book and allied areas. He also served as advisor to Reliance Industries limited for the development of roll-to-roll thin-film solar cell devices. His research areas include the development of low-cost CdTe, CuInGaSe2,Cu2 ZnSnS4, and tandem thin-film solar cells, organic field-effect transistors, memory devices, and high-k gate dielectrics.