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2. What is a Semiconductor? Electrons and Holes
About this Lecture
In this mini-lecture, we seek to understand how a semiconductor works. In particular, we consider: (i) the first recorded semiconductor effect by Michael Faraday in 1833; (ii) the unpopularity of semiconductors until the mid 20th century; (iii) Ohm’s Law and electrical conductivity of materials; (iv) the definition of a semiconductor: a material with electrical conductivity between that of insulators (low conductivity) and metals (high conductivity); (v) how semiconductors work by introducing the concept of the conduction band and the valence band (energy states of an atom that have been distorted and split), between which there is a band gap whose size determines whether the material is an insulator, a semiconductor, or a metal conductor; (vi) a snooker/billiards analogy to help us understand conduction, valence, and band gaps of different types of materials; (vii) methods to create electrons and holes in a material; and (viii) using impurities to create holes or electrons in a material, which results in p-type or n-type semiconductors, respectively.
In this course Professor Oleg Makarovskiy (University of Nottingham) explores semiconductors and their relevance in the current Information Age. In the first mini-lecture, we introduce the ages of human advancement, from the Stone Age up until the current Information Age, and consider the advancements in computers and information made in the 20th century. In the second mini-lecture, we discuss what a semiconductor is and how you can make one using electrons and ‘holes.’ In the third mini-lecture, we consider how semiconductors can be used to create light of various colours (LEDs) and transform light into electrical energy (solar cells). In the fourth mini-lecture, we explore how we can control semiconductor colour and how we can make low-dimensional semiconductors, such as quantum dots. In the fifth mini-lecture, we focus on understanding diodes and transistors and how these can be used to create microchips used in computers. Finally, in the sixth mini-lecture, we consider the next advancement in our Information Age, quantum information technology, and the role semiconductors play in this new Quantum Information Age.
Oleg Makarovskiy is an Associate Professor in the School of Physics & Astronomy at the University of Nottingham. His research focuses on experimental semiconductor physics, quantum phenomena in semiconductor nanostructures, and their applications in functional electronic and optoelectronic devices.
Cite this Lecture
Makarovskiy, O. (2022, January 25). Semiconductors in the Information Age - What is a Semiconductor? Electrons and Holes [Video]. MASSOLIT. https://massolit.io/courses/semiconductors-in-the-information-age/what-is-a-semiconductor-electrons-and-holes
Makarovskiy, O. "Semiconductors in the Information Age – What is a Semiconductor? Electrons and Holes." MASSOLIT, uploaded by MASSOLIT, 25 Jan 2022, https://massolit.io/courses/semiconductors-in-the-information-age/what-is-a-semiconductor-electrons-and-holes