About the lecture:
Semiconductor and Semiconductor devices, Dr. Sunil Kumar, Department of Engineering & Technology
Semiconductors are solids having conductivity much less than the metals and considerable more than insulators. Semiconductors are of two types: Intrinsic semiconductors and extrinsic semiconductors. Intrinsic semiconductors are pure semiconductors free from impurities while extrinsic semiconductors some impurities are added. Silicon and Germanium are the best examples of pure semiconductors or intrinsic semiconductors. In germanium, each atom is bonded with other atoms with 4 nearest atoms and they make a covalent bond, so there is no free electron available that is why pure semiconductor or intrinsic type semiconductor is treated as an insulator at 0 degrees Kelvin but when the temperature is increased a little bit some of the covalence bond breaks and the electrons become free for conduction but at room temperature, the conductivity is very small so in order to increase the conductivity we add some impurity and hence it becomes extrinsic type semiconductor. Adding impurities is termed as or is called doping. When the impurity atom has valency higher than the intrinsic type semiconductor it becomes n-type of the semiconductor on the other hand if the impurity atom has valency less than the intrinsic type semiconductor then it becomes a p-type semiconductor. For forming n-type of semiconductor in the case of germanium we must add a pentavalent atom because germanium is tetravalent, it can be arsenic or antimony, on the other hand in the case of p-type semiconductor we must have an impurity atom less than the intrinsic semiconductor for germanium it can be boron, the 3 boron atoms combine with 3 germanium atoms and hence 1 electron becomes free, the whole concentration in case of p-type of semiconductor increases, When p and n-type materials are brought close to giving a shape of p-n crystals there is a release of energy.
Watch Video Lecture:
Author:
Dr. Sunil Kumar
Professor-Department of Electrical & Electronics Engineering
Kalinga University, Raipur
Degrees: Ph. D. in Electronics, M. Sc. in Electronics and M. Tech
Areas of specialization: Optical Communication Antenna, Laser Technology
Author Biography:
Dr. Sunil Kumar is a Professor in the School of Electrical & Electronics Engineering at Kalinga University, New Raipur, Chhattisgarh, and has 25 years of Teaching & Administrative experience. He completed his M.Sc. in Electronics and M. Tech. from NIT Jamshedpur followed by Ph.D. (Electronics) from State Govt. University.
He has worked in reputed institutions of India such as Birla Engineering College, Dehradun University (DIT), Sri Sai University, etc on responsible and leading positions. He has published 40 Research Papers in highly reputed Journals and organized Conferences, Seminars, Workshops, and Chaired Technical Sessions.
Dr. Sunil Kumar has Guided various M. Tech Thesis and 2 Ph. D. has been awarded in Electronics under his supervision in 2014, and 6 Ph. D. scholars are currently doing research under his supervision.
He has written a book for CSIR & GATE Examinations. Dr. Kumar is Chairman of the Board of Study and Member of the Academic Council of various Universities. He is an Advisory Board member of 2 reputed Universities of Rajasthan.
He is also the Editor of 20 reputed International Journals and reviewed a number of papers of National and International authors.
