This book covers the two most important applications of. Diodes and transistors university of california, berkeley. I understand that doping introduces free electrons in the ndoped. These two emerging industries based on pn junctions make a significant contribution to the reduction in fossil fuel consumption. The pn junction is the fundamental building block of the electronic age. In total, semiconductor physics and devices contains 10 chapters.
If we join a piece of p type material to a pieceof n type material such that the crystalstructure. A diode is also a tool that exclusively permits unidirectional flow of current if the diode is operated at a particular voltage level. Silicon a single silicon atom consists of fourteen negatively. When ptype and ntype materials are placed in contact with each other, the junction behaves very differently. Parker advanced level physics heinemann educational books 1970 acrobat 7 pdf 47. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. The current in a pn junction is given by k b i o e evk bt 1 where i o is reverse saturation current, v is potential difference across the diode, and k b is the boltzmann constant.
As the base is thin and lightly doped, then it will not work as a pn junction. Materials, devices and simple circuits download ncert solutions for class 12 physics link of pdf file is given below at the end of the questions list. Pn junction also known as a diode one of the basics of semiconductor technology created by placing ntype and p type material in close contact diffusion mobile charges holes in p. Physics notes class 12 pdf r k maliks newton classes. Working of pn junction diode with biasing, characteristics. During forward biasing, holes move towards n side and electrons move towards p side. Such junctions show a pronounced rectifying behavior. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. Some of the chapters in this book include nonequilibrium excess carriers in semiconductors, pn junction diode and semiconductor heterostructure, special semiconductor devices and advance processes, introduction to the quantum theory of solids, and physics and crystal properties of semiconductors. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. Pn junction physics from ece 340 at california state university, northridge.
Pn junction one of the crucial keys to solid state electronics is the nature of the pn junction. Higher physics second in a series of 3 videos on semiconductors. Device physics i pn junctions junction capacitance martin p. Answers to selected problems in the back of the book. Pdf semiconductor physics and devices by donald neamen.
Physics of semiconductor devices pn junction depletion width problem a silicon pn diode has a doping of n d 81015 1 cm3 and n a 210 16 1 cm3. Writing a book on semiconductor device physics and design is never complete and probably never completely satisfying. Pn junction physics ece340 electronics i pn junction. Led, photodiode, solar cell and zener diode and their characteristics. Theres one well, probably more, but right now im hung up on this one aspect of pn junction diodes that doesnt quite make sense to me. Starting from the structure of matter and various types of bonds in the first chapter the mechanical properties. An arrangement consisting a p type semiconductor brought into a close contact with ntype semiconductor, is called a p n junction.
Similarly, holes flow by diffusion from the ptype side to the ntype side. Physics of semiconductor devices pn junction depletion. Most semiconductor devices contain at least one junction between ptype and ntype material. Pn junction under reverse bias p connected to negative terminal of battery, n connected to positive terminal at n, electrons move towards the positive terminal, creating a larger area of. This video covers the formation of the pn junction and how it performs when.
A light emitting diode led is essentially a pn junction diode. This is a book which covers the topic of solid state physics comprehensively. Since the ntype region has a high electron concentration and the ptype a high hole concentration, electrons diffuse from the ntype side to the ptype side. When carriers are injected across a forwardbiased junction, it emits incoherent light. They are also called pn diodes in analogy with vacuum diodes. P type and n type semiconductors, takenseparately are of very limited use. Coed school kolar road bhoapl department of physics project report investigatoryproject on pn junction and diodes project report submitted by govind patel submitted to mrs ratna hajela registerationno. N junction acts as a closed switch when it is forward biased, i. By exploring the electrical properties of silicon, it is possible to acquire an. The diffusion of electrons and holes into the depletion layer decreases its width. The biased pn junction an externally applied potential will alter the potential difference between the pand nregions.
The p positive side contains an excess of holes, while. If an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions. During the formation of pn junction diffusion process takes place in which the free electrons cross the boundary of the pn and joined with the holes in the ptype. Pn junctions are formed by joining ntype and ptype semiconductor materials, as shown below. Most of the commercial leds are realized using a highly doped n and a p junction. Pn junction theory serves as the foundation of the physics of semiconductor devices. When a ptype and ntype material are brought in contact, a number of interesting properties arise. This in turn will modify the flow of majority carriers, so that the junction can be used as. In other words, minority carrier injection happens on both pside in a normal diode without bias electrons are a minority on pside and nside holes are a minority on n.
So, out of the 4 n electrons, 2 n electrons are in the 2 n sstates orbital quantum number l 0 and 2n electrons are in the available 6n pstates. It acts as an open circuit when it is reversed biased, i. Updated discussion of device fabrication processes and. Pn junctions consist of two semiconductor regions of opposite type. Full practical pn junction diode with readings, download pdf.
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