The attached narrated power point presentation mentions the different materials used for the construction of semiconductors. It offers structural and energy level explanation on the properties exhibited by the semiconductor materials. It also throws light on the structure and behaviour of a PN junction and use of PN junctions in active electronic components. The material will be useful for KTU first year students who prepare for the subject EST 130, Part B, Basic Electronics Engineering.
This document provides an overview of active electronic components, including vacuum tubes, diodes, transistors, and integrated circuits. It describes the basic workings and applications of key components such as silicon and germanium diodes, zener diodes, bipolar junction transistors, field effect transistors, and integrated circuits. Common component identifiers and symbols are also explained.
The document summarizes key concepts about semiconductors and pn junctions. It discusses how semiconductors have properties between conductors and insulators. Intrinsic semiconductors have few charge carriers, while extrinsic semiconductors are doped with impurities to increase charge carriers, making them n-type or p-type. A pn junction forms at the interface of a p-type and n-type semiconductor, creating a depletion region and potential barrier. Forward biasing reduces and reverse biasing increases the potential barrier.
This document provides an overview of semiconductor physics, PN junction diodes, and resistors. It discusses semiconductor fundamentals including doping, the PN junction, and the diode equation. It explains that semiconductors have a moderate energy gap allowing a few electrons to jump between the valence and conduction bands, leaving holes. Doping with elements of 5 or 3 outer electrons introduces extra electrons or holes, improving conduction. The PN junction forms where P and N materials meet, blocking current in one direction.
This slide give you idea about the atomic structure, classification of solids based on valance electron, free electron, energy band description, why the silicon is used as semiconductor substance compare to germanium, semiconductor and its types.
This document summarizes key concepts about semiconductors. It discusses intrinsic and extrinsic semiconductors, energy levels, characteristics like bipolar charge carriers and temperature dependence. It also describes diodes, doping, forward and reverse bias, I-V characteristics, rectifiers, and transistors. It notes that semiconductors are the foundation of modern electronics, from early vacuum tubes to today's 14nm transistors, and are used widely in applications. The document was presented by six students to their professor.
This document provides information on advancements in semiconductors and superconductors. It defines semiconductors and describes their intrinsic and extrinsic types. Applications of semiconductors include displays, RFID tags, and solar cells. Superconductors are materials that conduct electricity without resistance below a critical temperature. The document defines key terms related to superconductors like critical temperature and Meissner effect, and provides examples of superconducting materials like YBa2Cu307.
This document discusses semiconductor materials and PN junction diodes. It explains that semiconductors have a small energy gap between the valence and conduction bands, allowing some electrons to become free carriers. Doping a semiconductor with impurities introduces free electrons or holes, making it an N-type or P-type semiconductor. When a P-type and N-type semiconductor are joined, a PN junction is formed. A PN junction diode has rectifying properties and only conducts current easily in one direction depending on whether it is forward or reverse biased.
The attached narrated power point presentation mentions the different materials used for the construction of semiconductors. It offers structural and energy level explanation on the properties exhibited by the semiconductor materials. It also throws light on the structure and behaviour of a PN junction and use of PN junctions in active electronic components. The material will be useful for KTU first year students who prepare for the subject EST 130, Part B, Basic Electronics Engineering.
This document provides an overview of active electronic components, including vacuum tubes, diodes, transistors, and integrated circuits. It describes the basic workings and applications of key components such as silicon and germanium diodes, zener diodes, bipolar junction transistors, field effect transistors, and integrated circuits. Common component identifiers and symbols are also explained.
The document summarizes key concepts about semiconductors and pn junctions. It discusses how semiconductors have properties between conductors and insulators. Intrinsic semiconductors have few charge carriers, while extrinsic semiconductors are doped with impurities to increase charge carriers, making them n-type or p-type. A pn junction forms at the interface of a p-type and n-type semiconductor, creating a depletion region and potential barrier. Forward biasing reduces and reverse biasing increases the potential barrier.
This document provides an overview of semiconductor physics, PN junction diodes, and resistors. It discusses semiconductor fundamentals including doping, the PN junction, and the diode equation. It explains that semiconductors have a moderate energy gap allowing a few electrons to jump between the valence and conduction bands, leaving holes. Doping with elements of 5 or 3 outer electrons introduces extra electrons or holes, improving conduction. The PN junction forms where P and N materials meet, blocking current in one direction.
This slide give you idea about the atomic structure, classification of solids based on valance electron, free electron, energy band description, why the silicon is used as semiconductor substance compare to germanium, semiconductor and its types.
This document summarizes key concepts about semiconductors. It discusses intrinsic and extrinsic semiconductors, energy levels, characteristics like bipolar charge carriers and temperature dependence. It also describes diodes, doping, forward and reverse bias, I-V characteristics, rectifiers, and transistors. It notes that semiconductors are the foundation of modern electronics, from early vacuum tubes to today's 14nm transistors, and are used widely in applications. The document was presented by six students to their professor.
This document provides information on advancements in semiconductors and superconductors. It defines semiconductors and describes their intrinsic and extrinsic types. Applications of semiconductors include displays, RFID tags, and solar cells. Superconductors are materials that conduct electricity without resistance below a critical temperature. The document defines key terms related to superconductors like critical temperature and Meissner effect, and provides examples of superconducting materials like YBa2Cu307.
This document discusses semiconductor materials and PN junction diodes. It explains that semiconductors have a small energy gap between the valence and conduction bands, allowing some electrons to become free carriers. Doping a semiconductor with impurities introduces free electrons or holes, making it an N-type or P-type semiconductor. When a P-type and N-type semiconductor are joined, a PN junction is formed. A PN junction diode has rectifying properties and only conducts current easily in one direction depending on whether it is forward or reverse biased.
This document discusses different types of junctions formed between materials, specifically metal-metal and metal-semiconductor junctions. Metal-metal junctions can form thermocouples, which use the Seebeck effect to generate voltage from a temperature difference. A metal-semiconductor junction is either a Schottky junction, where the metal work function is higher than the semiconductor, or an ohmic junction, where the semiconductor work function is higher. Schottky junctions form a barrier for electron flow while ohmic junctions allow current conduction in both directions.
This document provides an overview of semiconductor fundamentals and classifications. It discusses the properties of metals, insulators, and semiconductors. Semiconductors are classified as elemental, compound, narrow band-gap, wide band-gap, oxide, magnetic, organic, and low-dimensional. Elemental semiconductors like silicon are widely used but have limitations for optoelectronics. Compound semiconductors like GaAs have advantages for applications requiring high speeds or light emission/detection.
The document discusses the basics of semiconductor materials. It begins by reviewing the atomic model and how electrons are arranged in energy levels. Intrinsic semiconductors like silicon have electrons that can be excited into the conduction band to allow current flow. Semiconductor crystals form a lattice structure through covalent bonding. Doping introduces impurities to semiconductors to improve electrical properties by adding extra electrons or holes. A p-n junction forms the basis of semiconductor devices like diodes, which allow current to flow in one direction depending on bias polarity.
This document summarizes key concepts about semiconductors. It describes how semiconductor materials like silicon can be made to conduct electricity through doping, which involves adding impurities to the crystal lattice structure. Doping can produce either N-type semiconductors with extra electrons or P-type semiconductors with electron holes. Current then flows through the movement of these electrons or holes when a voltage is applied. The document outlines the basic properties and behaviors of semiconductors that make them useful in electronic devices.
Semiconductors are substances that can conduct electricity under some conditions but not others. They have resistivity between metals and insulators. There are two types - elemental semiconductors consisting of a single element like silicon or germanium, and compound semiconductors consisting of multiple elements like indium phosphide. In semiconductors, energy levels split into permitted energy bands separated by a forbidden energy gap when atoms are close together. The valence band is filled with electrons and the conduction band above it is empty or partially filled, with a gap between them through which electrons need energy to move.
1. When a P-type semiconductor is joined with an N-type semiconductor, a PN junction is formed known as a semiconductor diode.
2. Semiconductor diodes are widely used as rectifiers to convert alternating current (AC) input into direct current (DC) output.
3. In a PN junction, the diffusion of majority carriers across the junction leaves behind charged acceptor and donor ions which form an electric field called the depletion region or space charge region.
This document discusses how transformers work and their key components and properties:
1. Transformers transfer electric power from one circuit to another without changing frequency by using electromagnetic induction. They have a primary winding and secondary winding.
2. An alternating current in the primary winding produces a changing magnetic field that induces a voltage in the secondary winding. The ratio of turns between the windings determines the ratio of voltages.
3. Losses in transformers include iron losses from eddy currents and hysteresis in the core, and copper losses from resistance in the windings. The condition for maximum efficiency is when iron and copper losses are equal and minimum.
The following presentation is a part of the level 4 module -- Electrical and Electronic Principles. This resources is a part of the 2009/2010 Engineering (foundation degree, BEng and HN) courses from University of Wales Newport (course codes H101, H691, H620, HH37 and 001H). This resource is a part of the core modules for the full time 1st year undergraduate programme.
The BEng & Foundation Degrees and HNC/D in Engineering are designed to meet the needs of employers by placing the emphasis on the theoretical, practical and vocational aspects of engineering within the workplace and beyond. Engineering is becoming more high profile, and therefore more in demand as a skill set, in today’s high-tech world. This course has been designed to provide you with knowledge, skills and practical experience encountered in everyday engineering environments.
This document provides an introduction to semiconductor physics and materials. It discusses intrinsic and extrinsic semiconductors, and how doping creates an excess or deficiency of charge carriers. Current flow in semiconductors occurs through drift, driven by an electric field, and diffusion, driven by concentration gradients. Key parameters that determine conductivity include carrier mobility and diffusion constants. A p-n junction diode is formed at the interface of p-type and n-type semiconductors.
Semiconductor materials like silicon can be made to conduct electricity through doping. Doping involves adding impurity atoms that add either extra electrons (N-type) or holes where electrons are missing (P-type). The presentation covers the crystal lattice structure of semiconductors and how current flows differently in N-type and P-type materials when a voltage is applied. It also defines key terms like intrinsic conductivity, doping, and the two main types of semiconductors: N-type and P-type.
Semiconductor materials have intermediate conductivity between conductors and insulators. They are made from elements in groups III and V of the periodic table, like silicon and germanium. Doping involves adding small amounts of other elements to change the number of free electrons and create n-type or p-type semiconductors. Diodes allow current to flow in only one direction, while transistors can amplify small voltages or currents to control larger currents. Common semiconductor devices include diodes, transistors, LEDs, and integrated circuits which are used in applications such as power supplies, amplifiers, and microprocessors.
This document discusses semiconductors and their types. It defines a semiconductor as a material with conductivity between a metal and an insulator. There are two types of semiconductors - intrinsic and extrinsic. Intrinsic semiconductors are pure, while extrinsic are doped with impurities to be either N-type (excess electrons) or P-type (excess holes). The document explains the carrier concentrations and energy band diagrams of the different semiconductor types.
This document discusses semiconductors, which have electrical conductivity between conductors and insulators. Semiconductors are the foundation of modern electronics and their properties rely on quantum physics. Their conductivity increases with temperature. Common semiconductor materials include silicon, germanium, and gallium compounds. Semiconductors are made useful through doping, which introduces impurities to greatly increase the number of charge carriers within the material. This allows semiconductor devices to control and shape electrical currents.
1) Semiconductors exhibit characteristics between conductors and insulators. Diodes and transistors are early components made from semiconductors.
2) There are two types of semiconductors - intrinsic and extrinsic. Intrinsic semiconductors do not contain any foreign atoms while extrinsic are created by diffusing or implanting impurities into intrinsic semiconductors.
3) Extrinsic semiconductors can be n-type or p-type depending on the impurity used - n-type uses elements like phosphorus that add free electrons, while p-type uses elements like boron that create holes. The combination of n-type and p-type materials creates the PN
This document provides an introduction to semiconductors. It discusses how semiconductors can behave as either conductors or insulators depending on doping, and describes the crystal lattice structure of semiconductors. It also explains intrinsic and extrinsic semiconductors, detailing how doping with trivalent or pentavalent impurities creates N-type or P-type materials respectively. The document concludes by discussing diode operation under forward and reverse bias conditions.
This document provides an introduction to semiconductors. It discusses the atomic structure of conductors, semiconductors, and insulators. Semiconductors have electrical properties between conductors and insulators. Their atomic structure allows them to be doped to control conductivity. Intrinsic semiconductors like silicon form tightly bound crystals that do not conduct. However, doping silicon with trivalent or pentavalent impurities introduces charge carriers that allow conduction, creating n-type and p-type semiconductors.
This document provides an introduction to semiconductor devices. It discusses band theory and defines key concepts like the valence band, conduction band, and forbidden gap. It explains that semiconductors have a small forbidden gap that electrons can cross with a small amount of energy. Intrinsic and extrinsic semiconductors are introduced, along with p-type and n-type materials which are formed by doping. The document describes how a p-n junction forms a depletion zone and allows current to flow in one direction but not the other. Applications like solar cells, LEDs, and lasers are briefly outlined.
This document discusses semiconductors and their properties. It explains that semiconductors have electrical conductivity between conductors and insulators. Their valence and conduction bands are almost full and empty respectively, with a small energy gap that allows electrons to cross over with a smaller electric field compared to insulators. Common semiconductors like silicon and germanium form covalent bonds and have crystalline structures. Doping semiconductors with impurities can create an excess or shortage of electrons, making them either n-type or p-type semiconductors respectively.
The document discusses the physics of semiconductors including PN junction diodes and resistors. It covers semiconductor fundamentals like doping and intrinsic nature. It describes how doping materials like phosphorus or boron create N-type or P-type semiconductors. When an N-type and P-type material come into contact, a PN junction is formed with a depletion region and electric field. A PN junction acts as a switch that only allows current in one direction depending on whether it is forward or reverse biased.
Semiconductors are materials that have electrical conductivity between conductors and insulators. Their resistivity decreases as temperature increases, unlike metals. Semiconductors include silicon and gallium arsenide. Doping semiconductors with impurities can alter their conducting properties. The behavior of charge carriers in semiconductor junctions forms the basis of modern electronics like diodes and transistors. Common types of semiconductors are intrinsic, n-type and p-type.
The document summarizes research on magnetism at oxide interfaces. It discusses how interfaces between complex oxide materials like LaAlO3 and SrTiO3 can exhibit emergent properties not present in the constituent materials, such as ferromagnetism. Experimental techniques like SQUID, torque magnetometry, and XMCD are used to study the magnetic behavior and determine its origin. Theoretical predictions and XAS data indicate the magnetism arises from a reconstructed dxy orbital state of interfacial Ti3+ ions enabled by symmetry breaking and electronic reconstruction at the interface. Potential device applications involving spin injection and field effect transistors are also presented.
Properties of solids (solid state) by Rawat's JFCRawat DA Greatt
The document summarizes the key electrical, magnetic, and dielectric properties of solids. It discusses how solids can be classified as conductors, insulators, or semiconductors based on their electrical conductivity. Semiconductors are further classified as intrinsic or extrinsic, with n-type and p-type extrinsic semiconductors discussed. Magnetic properties are also summarized, classifying materials as diamagnetic, paramagnetic, ferromagnetic, antiferromagnetic, or ferrimagnetic based on their behavior in magnetic fields. Finally, dielectric properties including piezoelectricity, pyroelectricity, ferroelectricity, and antiferroelectricity are briefly defined.
This document discusses different types of junctions formed between materials, specifically metal-metal and metal-semiconductor junctions. Metal-metal junctions can form thermocouples, which use the Seebeck effect to generate voltage from a temperature difference. A metal-semiconductor junction is either a Schottky junction, where the metal work function is higher than the semiconductor, or an ohmic junction, where the semiconductor work function is higher. Schottky junctions form a barrier for electron flow while ohmic junctions allow current conduction in both directions.
This document provides an overview of semiconductor fundamentals and classifications. It discusses the properties of metals, insulators, and semiconductors. Semiconductors are classified as elemental, compound, narrow band-gap, wide band-gap, oxide, magnetic, organic, and low-dimensional. Elemental semiconductors like silicon are widely used but have limitations for optoelectronics. Compound semiconductors like GaAs have advantages for applications requiring high speeds or light emission/detection.
The document discusses the basics of semiconductor materials. It begins by reviewing the atomic model and how electrons are arranged in energy levels. Intrinsic semiconductors like silicon have electrons that can be excited into the conduction band to allow current flow. Semiconductor crystals form a lattice structure through covalent bonding. Doping introduces impurities to semiconductors to improve electrical properties by adding extra electrons or holes. A p-n junction forms the basis of semiconductor devices like diodes, which allow current to flow in one direction depending on bias polarity.
This document summarizes key concepts about semiconductors. It describes how semiconductor materials like silicon can be made to conduct electricity through doping, which involves adding impurities to the crystal lattice structure. Doping can produce either N-type semiconductors with extra electrons or P-type semiconductors with electron holes. Current then flows through the movement of these electrons or holes when a voltage is applied. The document outlines the basic properties and behaviors of semiconductors that make them useful in electronic devices.
Semiconductors are substances that can conduct electricity under some conditions but not others. They have resistivity between metals and insulators. There are two types - elemental semiconductors consisting of a single element like silicon or germanium, and compound semiconductors consisting of multiple elements like indium phosphide. In semiconductors, energy levels split into permitted energy bands separated by a forbidden energy gap when atoms are close together. The valence band is filled with electrons and the conduction band above it is empty or partially filled, with a gap between them through which electrons need energy to move.
1. When a P-type semiconductor is joined with an N-type semiconductor, a PN junction is formed known as a semiconductor diode.
2. Semiconductor diodes are widely used as rectifiers to convert alternating current (AC) input into direct current (DC) output.
3. In a PN junction, the diffusion of majority carriers across the junction leaves behind charged acceptor and donor ions which form an electric field called the depletion region or space charge region.
This document discusses how transformers work and their key components and properties:
1. Transformers transfer electric power from one circuit to another without changing frequency by using electromagnetic induction. They have a primary winding and secondary winding.
2. An alternating current in the primary winding produces a changing magnetic field that induces a voltage in the secondary winding. The ratio of turns between the windings determines the ratio of voltages.
3. Losses in transformers include iron losses from eddy currents and hysteresis in the core, and copper losses from resistance in the windings. The condition for maximum efficiency is when iron and copper losses are equal and minimum.
The following presentation is a part of the level 4 module -- Electrical and Electronic Principles. This resources is a part of the 2009/2010 Engineering (foundation degree, BEng and HN) courses from University of Wales Newport (course codes H101, H691, H620, HH37 and 001H). This resource is a part of the core modules for the full time 1st year undergraduate programme.
The BEng & Foundation Degrees and HNC/D in Engineering are designed to meet the needs of employers by placing the emphasis on the theoretical, practical and vocational aspects of engineering within the workplace and beyond. Engineering is becoming more high profile, and therefore more in demand as a skill set, in today’s high-tech world. This course has been designed to provide you with knowledge, skills and practical experience encountered in everyday engineering environments.
This document provides an introduction to semiconductor physics and materials. It discusses intrinsic and extrinsic semiconductors, and how doping creates an excess or deficiency of charge carriers. Current flow in semiconductors occurs through drift, driven by an electric field, and diffusion, driven by concentration gradients. Key parameters that determine conductivity include carrier mobility and diffusion constants. A p-n junction diode is formed at the interface of p-type and n-type semiconductors.
Semiconductor materials like silicon can be made to conduct electricity through doping. Doping involves adding impurity atoms that add either extra electrons (N-type) or holes where electrons are missing (P-type). The presentation covers the crystal lattice structure of semiconductors and how current flows differently in N-type and P-type materials when a voltage is applied. It also defines key terms like intrinsic conductivity, doping, and the two main types of semiconductors: N-type and P-type.
Semiconductor materials have intermediate conductivity between conductors and insulators. They are made from elements in groups III and V of the periodic table, like silicon and germanium. Doping involves adding small amounts of other elements to change the number of free electrons and create n-type or p-type semiconductors. Diodes allow current to flow in only one direction, while transistors can amplify small voltages or currents to control larger currents. Common semiconductor devices include diodes, transistors, LEDs, and integrated circuits which are used in applications such as power supplies, amplifiers, and microprocessors.
This document discusses semiconductors and their types. It defines a semiconductor as a material with conductivity between a metal and an insulator. There are two types of semiconductors - intrinsic and extrinsic. Intrinsic semiconductors are pure, while extrinsic are doped with impurities to be either N-type (excess electrons) or P-type (excess holes). The document explains the carrier concentrations and energy band diagrams of the different semiconductor types.
This document discusses semiconductors, which have electrical conductivity between conductors and insulators. Semiconductors are the foundation of modern electronics and their properties rely on quantum physics. Their conductivity increases with temperature. Common semiconductor materials include silicon, germanium, and gallium compounds. Semiconductors are made useful through doping, which introduces impurities to greatly increase the number of charge carriers within the material. This allows semiconductor devices to control and shape electrical currents.
1) Semiconductors exhibit characteristics between conductors and insulators. Diodes and transistors are early components made from semiconductors.
2) There are two types of semiconductors - intrinsic and extrinsic. Intrinsic semiconductors do not contain any foreign atoms while extrinsic are created by diffusing or implanting impurities into intrinsic semiconductors.
3) Extrinsic semiconductors can be n-type or p-type depending on the impurity used - n-type uses elements like phosphorus that add free electrons, while p-type uses elements like boron that create holes. The combination of n-type and p-type materials creates the PN
This document provides an introduction to semiconductors. It discusses how semiconductors can behave as either conductors or insulators depending on doping, and describes the crystal lattice structure of semiconductors. It also explains intrinsic and extrinsic semiconductors, detailing how doping with trivalent or pentavalent impurities creates N-type or P-type materials respectively. The document concludes by discussing diode operation under forward and reverse bias conditions.
This document provides an introduction to semiconductors. It discusses the atomic structure of conductors, semiconductors, and insulators. Semiconductors have electrical properties between conductors and insulators. Their atomic structure allows them to be doped to control conductivity. Intrinsic semiconductors like silicon form tightly bound crystals that do not conduct. However, doping silicon with trivalent or pentavalent impurities introduces charge carriers that allow conduction, creating n-type and p-type semiconductors.
This document provides an introduction to semiconductor devices. It discusses band theory and defines key concepts like the valence band, conduction band, and forbidden gap. It explains that semiconductors have a small forbidden gap that electrons can cross with a small amount of energy. Intrinsic and extrinsic semiconductors are introduced, along with p-type and n-type materials which are formed by doping. The document describes how a p-n junction forms a depletion zone and allows current to flow in one direction but not the other. Applications like solar cells, LEDs, and lasers are briefly outlined.
This document discusses semiconductors and their properties. It explains that semiconductors have electrical conductivity between conductors and insulators. Their valence and conduction bands are almost full and empty respectively, with a small energy gap that allows electrons to cross over with a smaller electric field compared to insulators. Common semiconductors like silicon and germanium form covalent bonds and have crystalline structures. Doping semiconductors with impurities can create an excess or shortage of electrons, making them either n-type or p-type semiconductors respectively.
The document discusses the physics of semiconductors including PN junction diodes and resistors. It covers semiconductor fundamentals like doping and intrinsic nature. It describes how doping materials like phosphorus or boron create N-type or P-type semiconductors. When an N-type and P-type material come into contact, a PN junction is formed with a depletion region and electric field. A PN junction acts as a switch that only allows current in one direction depending on whether it is forward or reverse biased.
Semiconductors are materials that have electrical conductivity between conductors and insulators. Their resistivity decreases as temperature increases, unlike metals. Semiconductors include silicon and gallium arsenide. Doping semiconductors with impurities can alter their conducting properties. The behavior of charge carriers in semiconductor junctions forms the basis of modern electronics like diodes and transistors. Common types of semiconductors are intrinsic, n-type and p-type.
The document summarizes research on magnetism at oxide interfaces. It discusses how interfaces between complex oxide materials like LaAlO3 and SrTiO3 can exhibit emergent properties not present in the constituent materials, such as ferromagnetism. Experimental techniques like SQUID, torque magnetometry, and XMCD are used to study the magnetic behavior and determine its origin. Theoretical predictions and XAS data indicate the magnetism arises from a reconstructed dxy orbital state of interfacial Ti3+ ions enabled by symmetry breaking and electronic reconstruction at the interface. Potential device applications involving spin injection and field effect transistors are also presented.
Properties of solids (solid state) by Rawat's JFCRawat DA Greatt
The document summarizes the key electrical, magnetic, and dielectric properties of solids. It discusses how solids can be classified as conductors, insulators, or semiconductors based on their electrical conductivity. Semiconductors are further classified as intrinsic or extrinsic, with n-type and p-type extrinsic semiconductors discussed. Magnetic properties are also summarized, classifying materials as diamagnetic, paramagnetic, ferromagnetic, antiferromagnetic, or ferrimagnetic based on their behavior in magnetic fields. Finally, dielectric properties including piezoelectricity, pyroelectricity, ferroelectricity, and antiferroelectricity are briefly defined.
This document discusses molecular bonding, energy states of molecules, bonding in solids, and electrical properties of materials. It begins by explaining different types of molecular bonding mechanisms including ionic, covalent, van der Waals, and hydrogen bonding. It then discusses the energy states and spectra of molecules, including rotational, vibrational, and electronic transitions. The document next summarizes bonding in ionic solids, covalent solids, and metallic solids. It concludes by covering electrical conduction in metals, insulators, and semiconductors, as well as properties and applications of superconductivity.
This document provides an outline and overview of solid state physics concepts including ionic and covalent bonding, types of solids, band theory, and free electron models. Band theory describes how the energy levels of isolated atoms combine and split into allowed energy bands as atoms are brought together in a solid. Key concepts covered include the formation of valence and conduction bands, density of states, and Fermi energy. Free electron models are discussed as approximations to describe conduction in metals, along with limitations like Bragg reflection. The nearly-free electron model incorporates effects of the periodic lattice potential through concepts like Bloch waves and effective mass.
This document provides an outline and overview of solid state physics concepts including ionic and covalent bonding, types of solids, band theory, and free electron models. Band theory describes how the energy levels of isolated atoms combine and split into allowed energy bands as atoms are brought together in a solid. Key concepts covered include the formation of valence and conduction bands, density of states, and Fermi energy. Free electron models are discussed as approximations to describe conduction in metals, but limitations are noted. The nearly-free electron model incorporates effects of the periodic lattice potential through concepts such as Bloch waves and effective mass.
This document discusses band theory and several models used to describe electron behavior in solids, including the free electron model, nearly free electron model, and tight binding model. It provides an overview of each model, including their assumptions and how they describe properties like electron energy and band gaps. The free electron model treats electrons as independent particles but fails to explain material properties. The nearly free electron model incorporates a periodic potential and allows electron wavefunctions and energy bands to be described. The tight binding model uses a superposition of atomic orbitals to approximate electron wavefunctions in solids where potential is strong.
This document is a presentation on spintronics given by Md. Faruk Hossain at Rajshahi University of Engineering & Technology. It provides a brief history of spintronics, defines what spintronics is, and describes some of the key devices and effects in spintronics including giant magnetoresistance, tunnel magnetoresistance, magnetic tunnel junctions, MRAM, and spin field-effect transistors. The presentation outlines both the current state of spintronics research and its potential advantages over conventional electronics, as well as some remaining limitations that need to be addressed.
This document discusses Mossbauer spectroscopy and the different types of interactions that can be observed. It explains that three main types of interactions are the isomer shift, quadrupole splitting, and magnetic Zeeman splitting. The quadrupole splitting arises due to the interaction between the electric quadrupole moment of the nucleus and an electric field gradient. This splitting results in multiple peaks in the Mossbauer spectrum equal to I+1/2, where I is the nuclear spin. Factors like ligand asymmetry and electronic asymmetry can also influence the quadrupole splitting. The document provides examples to illustrate these concepts.
1) Atoms bond through ionic, covalent, and metallic bonding depending on their positions on the periodic table and electronegativity differences.
2) Ionic bonding occurs between ions and involves electron transfer, covalent bonding involves sharing electrons between atoms, and metallic bonding arises from a "sea" of delocalized electrons between fixed ion cores.
3) Secondary intermolecular forces like hydrogen bonding and van der Waals forces provide weaker bonding between molecules.
1) Atoms bond through ionic, covalent, and metallic bonding depending on their positions on the periodic table and electronegativity differences.
2) Ionic bonding occurs between ions and involves electron transfer, covalent bonding involves sharing electrons between atoms, and metallic bonding arises from a "sea" of delocalized electrons between fixed ion cores.
3) Secondary intermolecular forces like hydrogen bonding and van der Waals forces provide weaker bonding between molecules.
This document provides an overview of the key topics in Unit 3 of the Applied Physics course. The unit covers:
1. Classical and quantum free electron theories of metals, including the Drude-Lorentz model and Sommerfeld's quantum model.
2. Mean free path, relaxation time, and drift velocity of electrons in metals.
3. The Fermi level and Fermi-Dirac distribution of electron energies.
4. Classification of materials as insulators, semiconductors, or conductors based on their band structure and energy gaps.
1. The document provides an overview of an introductory materials science and engineering course. It lists the instructor, their contact information, course website, and lab teaching assistants.
2. Materials are discussed through different historical ages from stone to modern materials like polymers and semiconductors. Key developments in processing and understanding of materials structures and properties are highlighted.
3. The document covers fundamental materials science topics like atomic structure, bonding, crystal structures, and how they influence materials properties. Different types of bonding and structures are compared.
Apartes de la Conferencia de la SJG del 14 y 21 de Enero de 2012Nonlinear ele...SOCIEDAD JULIO GARAVITO
This document summarizes a research article about nonlinear electrodynamics and its effects on the polarization of the cosmic microwave background radiation. It introduces nonlinear electrodynamics models as alternatives to Maxwell's electrodynamics. The document then discusses how nonlinear electrodynamics is minimally coupled to gravity and derives the relevant equations of motion. It focuses on analyzing the Pagels-Tomboulis nonlinear electrodynamics Lagrangian and computing the polarization angle of photons propagating in an expanding universe with planar symmetry. Constraints on the nonlinear electrodynamics parameter are obtained using data on cosmic magnetic field strengths and the rotation of CMB polarization spectra measured by experiments.
This presentation gives you idea about following topics
1.atomic structure
2.classification of solids based valance electron, free electron, energy band description
3.semiconductor and its type
1. The document provides information on molecular structure and bonding theories including atomic and molecular orbitals, linear combination of atomic orbitals, molecular orbital diagrams of diatomic molecules like N2, O2 and F2, π molecular orbitals of butadiene and benzene, and crystal field theory.
2. Key concepts covered include how molecular orbitals are formed from the overlap and combination of atomic orbitals, bonding and anti-bonding molecular orbitals, and how molecular orbital diagrams can be used to explain bonding properties.
3. Crystal field theory is introduced as explaining the color, magnetic properties and other characteristics of crystalline substances based on interactions between the d-orbitals of metal ions and ligand ions or molecules
This document provides an introduction to the thesis which focuses on aspects of symmetry, disorder and the Josephson effect in d-wave superconductors. Some key points:
- The thesis studies d-wave superconductors where the gap function changes sign in certain crystal directions, in contrast to conventional s-wave superconductors where the gap is isotropic.
- For a disordered d-wave superconductor, numerical, perturbative and field theoretical methods are used to calculate the density of states, finding it follows a sublinear power law at low energies.
- The Josephson effect in d-wave superconductors is investigated using a tunneling Hamiltonian approach to understand experiments on bicrystal junctions
Spintronics also known as spin electronics, is the study of the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices
The document is an introduction to periodicity for A-level chemistry students. It discusses the organization of the periodic table by atomic number into rows and columns. It also summarizes trends in various atomic properties across period 3, including atomic radius decreasing due to nuclear charge, ionization energy generally increasing due to nuclear charge but with exceptions, electrical conductivity decreasing for nonmetals with no delocalized electrons, electronegativity increasing with nuclear charge, and melting point generally increasing for metals due to metallic bonding but decreasing for nonmetals due to weaker van der Waals forces.
Semiconductor theory describes how small amounts of impurities can be added to intrinsic semiconductors to create n-type and p-type materials. N-type semiconductors are created by adding elements with extra electrons, while p-type are created by adding elements with electron deficiencies. The junction between a p-type and n-type material allows current to flow in only one direction, forming the basis for important semiconductor devices such as diodes, transistors, and solar cells.
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Energy band structure and electrical conductivity mechanisms of metals and semiconductors
1. 12/17/2019 1
Energy Band Structure And Electrical Conductivity
Mechanisms of Metals And Semiconductors
1
Krishna Jangid
PhD Student
Department of Engineering Physics
2. Energy band structure of Metals and Semiconductors
Formation of band
(Metal)
Categorization of materials
2
3. 𝑓 𝐸 =
1
ⅇ 𝐸−𝐸 𝐹 𝑘 𝐵 𝑇+1
Energy band structure of Metals and Semiconductors
3
4. Energy band structure of Metals and Semiconductors
Metals Semiconductors/Insulators
4
Overlapping of bands in Mg Bands in Silicon
5. Electrical conductivity of metals
𝐹 = 𝑚
ⅆ𝑣
ⅆ𝑡
= ℏ
ⅆ𝑘
ⅆ𝑡
= −ⅇ𝐸
𝛿𝑘 = −
ⅇ𝐸𝑡
ℏ
𝑗 = 𝑛𝑞𝑣 = 𝑛ⅇ2
𝜏 𝐸 𝑚
𝑗 = 𝜎𝐸
𝜌 =
𝑚
𝑛ⅇ2 𝜏𝜎 =
𝑛ⅇ2 𝜏
𝑚
𝑣 =
ℏ𝑘
𝑚
𝜏 is the collision time
5
Fermi sphere under the influence of Force F
6. Factors affecting conductivity in metals
Scattering of
electrons by
Phonons
Normal
scattering
Umklapp
scattering
Electrons
Role of Pauli
exclusion
principle
Imperfections
Temperature
Phonon
concentration
Scattering
𝝈
Scattering
𝝆
6
7. Electrical conductivity of semiconductors
Intrinsic semiconductors
where, 𝑁𝐶 = 2
2𝛱𝑚 𝑛
∗ 𝑘𝑇
ℏ2
3/2
Concentration of electrons
in the conduction band
𝒏 =
𝐸 𝐶
∞
𝐷𝑒 𝐸 𝑓𝑒 𝐸 ⅆ𝐸
𝒏 = 𝑁𝑐 exp −
𝐸𝑐 − 𝐸 𝐹
𝑘𝑇
𝒏𝒊 = 2
2𝜋𝑘𝑇
ℎ2
3
2
𝑚 𝑛
∗
𝑚 𝑝
∗
3
4 exp
−𝐸𝑔
2𝑘𝑇
where, mn* and mp* are the effective
mass of electrons and holes
7
Electron concentration dependence on
temperature: (a) Ge; (b) Si
8. Electrical conductivity:
ln 𝜎 = −
𝐸 𝑔
2𝑘
1
𝑇
+
3
2
ln 𝑇 + constant𝝈 = 𝜎 𝑛 + 𝜎 𝑝 = ⅇ𝑛𝑖 𝜇 𝑛 + 𝜇 𝑝 = ⅇ 𝜇 𝑛 + 𝜇 𝑝
2 2𝜋𝑘𝑇 3/2
ℎ3
𝑚 𝑛
∗
𝑚 𝑝
∗ 3 4
exp
−𝐸𝑔
2𝑘𝑇
Intrinsic semiconductors (cont.)
Mobilities were assumed to be
independent of temperature
As scattering of electrons
affects conductivity
8
Electrical conductivity
vs Temperature
9. Extrinsic semiconductors
Electrical conductivity:
𝜎 = ⅇ𝑛𝜇 𝑛
• Mobilities were assumed to be
independent of temperature.
• Nd is assumed to be constant.
𝜎 = ⅇ𝜇 𝑛 𝑁𝑑 𝑁𝑐
1 2
exp
−𝐸𝑔
2𝑘𝑇
𝒍𝒏 𝝈 =
−𝐸𝑔
2𝐾
1
𝑻
+
1
2
ln 𝑵 𝒅 𝑁𝑐 + constant
Concentration of
electrons in the
conduction band
Carrier concentration:
𝒏 = 𝑵 𝒅 𝑁𝐶
1
2 exp
−𝐸𝑔
2𝐾𝑻
9
Carrier concentration dependence over temperature
Conductivity
dependence over
temperature
10. References
• Solid state physics by Puri and Babbar.
• Introduction to solid state physics by Charles kittel.
• Nanotechnology: Understanding Small Systems by Ben Rogers.
• NPTEL videos.