Semiconductor physics and material science have continued to prosper and to break new ground. Introduction in order to understand the physics of semiconductor sc devices, we should first learn how atoms bond together to form the solids. However, it was not until the twentieth century that the atomic theory of matter became firmly established as an unassailable, demonstrated fact. The physics of semiconductors an introduction including. Lawofmass action relates concentration of reactants. Guldberg and waages law of mass action is one of the basic laws of life. Physics is an important subject for class 12 science stream. This is caused by the instantaneous location of a few more electrons on one side of the nucleus than on the other.
The reason why your mental image of a semiconductor doesnt really help here, is because its actually impossible to distinguish whether a free. Draft material for fundamentals of plasma physics book. Applying the law of mass action to the above reaction, we can write for the equilibrium concentration of holes and electrons. The physics of semiconductors requires little or no prior knowledge of solidstate physics and evolved from a highly regarded twosemester course. Basic semiconductor material science and solidstate physics all terrestrial materials are made up of atoms. Semiconductor physics and materialsintrinsic and extrinsic semiconductors, conduction mechanism in extrinsic semiconductors, carrier concentrations, drift and diffusion mechanisms, drift and diffusion current densities, excess carriers, recombination process, mean carrier lifetime, conductivity, mobility, mass action law, einstein relationship. Pdf the law of mass action does not force a series of chemical reactions to have the same current flow everywhere. During doping, impurity atoms are introduced to an intrinsic semiconductor. Weve learned about how physical phenomena can represent and communicate information, and will learn about how it can be input, stored, and output, but here we turn to. Each part, you will learn the latest content and revised physics concepts. The book has multiple benefits from class 12 exam preparation to various entrance exam preparation. This law is also applicable to semiconductors and, therefore, has several important implications in the fields of electronics and semiconductor physics. Law of mass action according to law of mass action the product of majority and minority charge carrier concentration at a particular temperature is equal to the square of intrinsic carrier concentration at that particular temperature.
Weve learned about how physical phenomena can represent and communicate information, and will learn about how it can be input, stored, and output, but here we turn to the essential electronic devices that transform it. Lattice scattering occurs because atoms in a semiconductor contain a certain amount of thermal energy in the form of atomic vibrations. In recent years there has been much discussion of natural laws, typically laws in physics and economics. Assume that the mobility of a particular carrier is cm. Another way to get this result is to apply the law of mass action from chemistry relating the concentrations of the reactants and products in a reaction in thermal equilibrium. A semiconductor device which conducts electric current run in one direction only. Cbse syllabus for class 12 physics 20192020 pdf physics. The conductivity of a semiconductor material can be varied under an external electric field. Now dope it with a donor of concentration 1016 cm3. It can generally be taken to describe principles that apply universally to all reactions. The law of mass action for ntype semiconductor is mathematically written as.
One diode can be used as a halfwave rectifier or four as a. For example, in the years since the publication of the. In a semiconductor the law of mass action states that the product of the electron concentration and the hole concentration is always equal to the square of the intrinsic carrier concentration at a given temperature, i. It is addressed to both readers who wish to learn semiconductor physics and those seeking to understand semiconductor devices. Engineering physics pdf notes enginering physics notes. Vegards law says the lattice constant of an alloy is a weighted sum of the lattice constants of each of its constituents, and the weight aligned to each constituent is equal to its fraction is the alloy.
Imagine a regular crystal lattice composed of identical atoms. And the ashcroft and mermins book only helps to increase my confusion. This book will be useful to solidstate scientists, device engineers, and students involved in semiconductor design and technology. The book uses lecture style in explaining the concepts which would facilitate easy understanding of the concepts. The engineering physics notes pdf book starts with the topics covering ionic bond, covalent bond, metallic bond, basic principles, maxwellboltzman, electron in a periodic potential, fermi level in intrinsic and extrinsic semiconductors. Vegards law vegards law says the lattice constant of an alloy is a weighted sum of the lattice constants of each of its constituents, and the weight assigned to each constituent is. What is the theory behind mass action law in doped. Most semiconductors are formed from elements from groups ii, iii, vi, v, vi of the periodic table.
Is the principle of mass action law applicable in a pn. Sze contains the plot of intrinsic carrier densities. The law of mass action describes how the velocity of a chemical reaction is related to the molecular concentrations of the reactants. Review of basic semiconductor physics in this lecture you will learn. Basics of semiconductor devices department of electrical. Free download of the 5 pdf volumes of the motion mountain physics textbook. Devices made from semiconductor materials are the foundation of modern electronics, including ratio, computers. Medical physics, biophysics, medical physics and principles of ehealth 46 4. It is particularly well suited for those who want to do both. Law of mass action the np product is constant in te n o p o n i 2 t second equation where does this last equation come from. The topics have been dealt with precision and provide adequate knowledge of the subject. The semiconductor is in internal turmoil, with bonds being broken and reformed continuously.
This handbook gives a complete survey of the important topics and results in semiconductor physics. The law of mass action also suggests that the ratio of the reactant concentration and. Apart from this, there is also atomic physics that deals with subatomic particles and their interactions quantum mechanics. Impurity atoms are atoms of a different element than the atoms of the intrinsic semiconductor. For ntype semiconductor, the law of mass relation can be written as n n 1 for ptype semiconductor, the. In order to describe the motion of electrons and holes with the laws of motion of.
Jan 03, 2020 cbse ncert textbook for class 12 physics 201920 pdf. This is the same mass action principle that keeps the product of. Medical physics in questions and answers 6 angle acceleration. In electronics and semiconductor physics, the law of mass action is a relation about the. The electrons are the majority carriers and holes are the minority carriers in ntype semiconductor. The law of mass action describes reactants as simple ideal fluids of concentrations of. The law of mass action states that the product of number of electrons in the conduction band and the number of holes in the valence band is constant at a fixed temperature and is independent of amount of donor and acceptor impurity added. Physics notes class 12 pdf r k maliks newton classes. This book is an introduction to the principles of semiconductor physics, linking its scientific aspects with practical applications.
To determine the diffusion coefficient given the carrier mobility. Let a bar of silicon have an intrinsic concentration of 1010 cm3. Electrons and holes in semiconductors uc berkeley eecs. Browse other questions tagged quantummechanics condensedmatter temperature semiconductorphysics electronicbandtheory or. Short table of contents list of figures, list of tables title page table of contents. Law of mass action relates concentration of reactants. Physics 301 30nov2005 261 semiconductor basics in solids, the electron energy levels are organized into bands. It is equal to the product of mass m and centripetal acceleration ad, i. Introduction to semiconductors and semiconductor devices a background equalization lecture reading. Write the equilibrium constant expression for any reaction equation.
Regardless of doping, the product of electron and hole densities is a constant at equilibrium. Two scattering mechanisms are lattice scattering and impurity scattering. This may be considered as a sort of inheritance of the lyapunov functionals from the microscopic master equations. The law of mass action for intrinsic semiconductors is. This is the simplest kind of semiconductor device, it has two terminals and a single pn junction. Electrons in an isolated atom can only occupy discrete energy levels. For ntype semiconductor, the law of mass relation can be written as n n 1 for ptype semiconductor, the law of mass relation can be written as. For a given semiconductor the electron mobility is always higher than hole. Pdf mass action and conservation of current researchgate. Each of the known 118 elements has atoms that are different from the atoms of all other elements. The engineering physics notes pdf book starts with the topics covering ionic bond, covalent bond, metallic bond, basic principles, maxwellboltzman, electron in a periodic potential, fermi level in intrinsic and extrinsic semiconductors, electricsusceptibility. Alan doolittle for metals, the electrons can jump from the valence orbits outermost core energy levels of the atom to any position within the crystal free to move throughout the crystal with no extra energy needed to be supplied. For an intrinsic semiconductor, we have e e i, the intrinsic.
Typically, the dopant concentration is at least 47 orders of magnitude 107 larger than the intrinsic concentration. An introduction advanced texts in physics karlheinz seeger on. It addresses every fundamental principle and most research topics and areas of application in the field of semiconductor physics. Physics 468 and flow of charge carriers in the semiconductor devices are within the solid itself, while in the earlier vacuum tubesvalves, the mobile electrons were obtained from a heated cathode and they were made to flow in an. Impurity atoms act as either donors or acceptors to the intrinsic semiconduc. The law of mass action is applied for both intrinsic and extrinsic semiconductors. The primary objective of this book is to present and develop the fundamentals and principal applications of plasma physics, with an emphasis on what is usually called hightemperature plasma physics where the plasma is nearly fully ionized with nearly negligible effects of neutral particles on the plasma behavior. This law can be used to explain the behaviour exhibited by solutions in dynamic equilibria. When an atom is in a solid, these energy levels are smeared out into bands.
This law states the relation between concentrations of minority and majority carriers at a constant temperature. Apply the mass action law to write expressions for equilibrium constants. Atom is composed of a nucleus which contains protons and neutrons. Lecture 1 introduction to semiconductors and semiconductor. It states that product of concentration of majority and minority carrier is constant at fixed temperature. Solid state physics is written as per the core module syllabus of the major universities and targets undergraduate b. Ravindran, phy02e semiconductor physics, 26 december 2012. Physics stack exchange is a question and answer site for active researchers, academics and students of physics. In chemistry, the law of mass action is the proposition that the rate of the chemical reaction is. Electric potential, potential difference, electric potential due to a point charge, a dipole and system of charges. Brennan the physics of semiconductor devices solymar and walsh electrical properties of materials neudeck and pierret advanced semiconductor fundamentals. Semiconductor physics group cavendish laboratory jj thomson avenue cambridge, cb3 0he, uk. The law of mass action also has implications in semiconductor physics. Here you can download the free lecture notes of engineering physics pdf notes materials with multiple file links to download.
In this paper, we study nonlinear markov processes that inherit thermodynamic. Cbse ncert textbook for class 12 physics 201920 pdf. It states that, under thermal equilibrium, the product of the free electron concentration and the free hole concentration is equal to a constant square of intrinsic carrier concentration. Heat is energy flowing from a high temperature object to a low temperature object. Basic laws of physics that govern our universe can be categorized in two ways. Where n n number of electrons in ntype semiconductor. The law of mass action states that the rate of a reaction is proportional to the product of the concentrations of each reactant. For global equilibrium, the mass action law ne nh ni. Classical physics that deals with us, the surrounding environment and the observable universe around us. All semiconductor physics text books above a very basic level invariably assume that the reader is. May 09, 2015 typically, the dopant concentration is at least 47 orders of magnitude 107 larger than the intrinsic concentration.
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