Silicon. tetrahedron diamond structure

Size: px
Start display at page:

Download "Silicon. tetrahedron diamond structure"

Transcription

1 Silicon a tetrahedron a a diamond structure

2 Tetrahedral bonding Hund s Rule 14Si [e] 3s 3p [e] hybridize 3sp 3 Hybridized level has higher energy for an isolated atom, but allows overall reduction in energy when forming tetrahedral bonds in a solid. 3s 3p x 3p y 3p z s p x p y pz choose four from eight possibilities

3 Origin of bandgap isolated molecule pair of molecules crystal insulator: Eg kt Eg ~ 3 e semiconductor: semi-metal: 0.5 e E 3 e Eg ~ ~ g ~ e metal: no E g

4 Band structure indirect indirect direct

5 Bloch s Theorem Electron wave function in a crystal can be written: r u r e i kr The Block functions are periodic: urrur R n a n a n a where: is a lattice vector: ik rr ikr rr u rr e e r Translation by a lattice vector causes a change in phase only.

6 1 sinusoidal potential d q x x E x mdx Band iagram bx bn n e inx a 1 U x U0 x a 1cos Potential

7 1 sinusoidal potential: wave functions E=0.49 E= 0.46 E=

8 Electrons and holes Migration of an electron (negative charge) vacancy in one direction (left) is equivalent to the motion of a hole (positive charge) in the opposite direction (right). time semiconductor conductivity changes with: -doping -temperature -illumination

9 ermi-irac distribution 1 fee e EE kt 1 Gives the probability for occupation of an electron state in equilibrium ermi energy increasing T

10 arrier concentrations (I) As for photons, to find the # of electrons per unit electron energy, per unit volume, we need: i) density of states ii) distribution function dn de E f E umber of states from 0 to k: 4 3 g k 4 k 3 gk L L 3 3

11 arrier concentrations (II) ear the band edges: energy hk Ek E0 Ek E m c 0 hk m v EB k Effective masses: E 1 1 d E k m h dk k d E k m h dk k 0 E g k B: B: m 0 k EE h B case: 4 m 3 3 gl E EE 3 3h d m 3 3 m 0 k E E h 0 gl E EE de 3 h E EB k

12 arrier concentrations (III) B OS (per unit volume) : 3 E m g E 4 E E 3 L h B electron concentration (per unit energy): 3 E m g E 4 E 3 E L h 1 dn m 1 1 E f E E g E f E E 4 E E de EE kt h B OS (per unit volume) : e EE kt 1 e EE kt 1 B hole concentration (per unit energy): e 1 otice: So: 1 f EE f E E dp m 1 1 E 1 f E E g E f E E 4 E E de E E kt h e 1

13 arrier concentrations (I) p-type intrinsic n-type E g E g E g dn de dn de dn de E E E E E E E E E dp de dp de dp de g g g 3 dn m E E de EE kt h e 1 3 dp m E E de E E kt h e 1

14 arrier concentrations () Total conc. of electrons in the B (integrated over energy) 3 dn m EE EE EE kt n de EE de de h 1 E E x E E ktx efine: EE kt kt de ktx dx e e E E kt x e n 8 3 x 0 mkt x dx E E kt x h e e 1 e 1 on-degenerate case, (Boltzmann approx.): 1 EE kt x e e 1 e E E kt x e E E kt E E kt x E E kt e x e dxe x0 4 n mkt 3 e E E kt n h E E kt e //non-degenerate mkt h 3 // effective B density of states n E E kt //general 4 x dx y x0 y x e e 1

15 arrier concentrations (I) Total conc. of holes in the B (integrated over energy) E m 3 E 1 1 h E e 1 p de 4 E E de E E kt E dp de efine: x E E kt 1 E E ktx de ktx dx EE kt EE e e kt x e x E E kt x x0 EE kt x m kt x dx m kt x dx p 8 8 h e e 1 h e e 1 //integrand is even on-degenerate case, (Boltzmann approx.): 1 EE kt x e e 1 e 3 mkt h p e E E kt E E kt x e E E kt // effective B density of states //non-degenerate p E E kt //general

16 arrier concentrations (II) The ermi function reduces to the (simpler) Boltzmann function is sufficient when the occupation probability is low. E E kt E E kt e E E kt e E E kt Boltzmann 1 EE e kt 1 1 EE e kt 1 ermi E E kt otice: E E kt e E E kt

17 Semiconductors (I) We most often use an energy vs. position diagram, showing only band edges: n e E E kt energy E B edge E E g E position B edge p e E E kt

18 Semiconductors (II) otice: n p e E E kt Eg kt e n i n e i E g kt //intrinsic carrier conc. This is the # of electrons in B, and holes in B, respectively, of a pure semiconductor in equilibrium. We can write: nn p i n i e e i i E E kt E E kt E i E E kt E E 3kT m ln ln 4 m //intrinsic energy level If m m, then E is exactly in the center of the gap i i If E E, then n p n i (material is intrinsic).

19 Semiconductors (III) Somewhere above the B edge is the vacuum level: E vac (Electron is free from the solid) w //electron affinity E E E E E vac vac g E E E E E ktln ktln E n p w vac g w //work function E E ktln n E E ktln p In metals: w In semiconductors, w depends on doping.

20 Semiconductors: oping (I) If we substitute an atom in pure Si w/b or P, the dopant atom has one missing/extra valence electron: 14Si [e] 3sp 3 5B - [He] sp 3 15P + [e] 3sp 3 The dopant easily ionizes, either -accepting an electron (B) from the B, or -donating an electron (P) from the -These are called electron acceptors/donors

21 Semiconductors: oping (II) We can use the Bohr model to estimate the ionization energy of a dopant: oulomb potential: U r e e 4 r 4r 0 Bohr radius: a me 0 me The ionization energy of H is: 1 Ryd m 13.6 e 0 a0 The ionization energy of the dopant atom is: n m 0 * m a m 0 1 Ryd m //permittivity of solid //carrier effective mass

22 Semiconductors: oping (III) n E B electrons n E ionized donors A p p E E ionized acceptors B holes donors ionized neutral ionized donor level: E E n acceptors ionized neutral ionized acceptor level: E E A p

23 Semiconductors: oping (I) At T=0 K, dopant levels are neutral. With a single dopant, at room temp., start by assuming all shallow acceptors/donors are ionized. doped n-type n //donor conc. p ln E E kt n i A p A doped p-type //acceptor conc. n ln n i A A E E kt E E E E Ei Ei E doped n-type E doped p-type E A E

24 Semiconductors: oping () opant Levels in Si B. G. Streetman, Solid State Electronic evices, 3 rd Ed., Prentice Hall (1990).

25 Semiconductors: oping (I) Assume: ln E E kt n Adjust the fermi level: n E E E E E E E E n Iterate: Evaluate: f E E 1 EE e kt 1 (fraction not ionized, should be small) orrect n: n 1 f E E orrect E E :

26 Semiconductors: oping (II) Example: Si doped with P d cm e n 16 3 n 10 cm Trick: * m m * m m ln E E kt mkt.510 cm 19 3 E E e cm E E E E n e e e 3 E f E n 1 f E E cm nearly complete ionization: n 99.6% E E e

27 harge ensity x pxnx x x A charge density holes electrons ionized donors ionized acceptors harge neutrality in a uniformly doped region: nn i e pn i i E E kt e i E E kt negative positive A fe 1 EkT e 1 n p A A 1 A f E E Algorithm: If A n p, E 1 f E E If A n p, E

28 harge eutrality (I) A 0 If i and n p n n i p o-doping (both acceptors and donors): If nn A i we can still assume full ionization: A A However, A of the donated electrons serve to ionize (fill) the acceptor levels: ow nn Example: n i p n n 810 cm A cm 16 3 This is called compensation. na610 cm 16 3

ECE 442. Spring, Lecture -2

ECE 442. Spring, Lecture -2 ECE 442 Power Semiconductor Devices and Integrated circuits Spring, 2006 University of Illinois at Chicago Lecture -2 Semiconductor physics band structures and charge carriers 1. What are the types of

More information

EECS130 Integrated Circuit Devices

EECS130 Integrated Circuit Devices EECS130 Integrated Circuit Devices Professor Ali Javey 8/30/2007 Semiconductor Fundamentals Lecture 2 Read: Chapters 1 and 2 Last Lecture: Energy Band Diagram Conduction band E c E g Band gap E v Valence

More information

Basic cell design. Si cell

Basic cell design. Si cell Basic cell design Si cell 1 Concepts needed to describe photovoltaic device 1. energy bands in semiconductors: from bonds to bands 2. free carriers: holes and electrons, doping 3. electron and hole current:

More information

Chapter 2. Semiconductor Fundamentals

Chapter 2. Semiconductor Fundamentals hapter Semiconductor Fundamentals.0 Introduction There are altogether 9 types of natural occurring elements, of which only few types are important in semiconductor physics and technology. They are the

More information

Chapter 1 Semiconductor basics

Chapter 1 Semiconductor basics Chapter 1 Semiconductor basics ELEC-H402/CH1: Semiconductor basics 1 Basic semiconductor concepts Semiconductor basics Semiconductors, silicon and hole-electron pair Intrinsic silicon properties Doped

More information

Lecture 1. OUTLINE Basic Semiconductor Physics. Reading: Chapter 2.1. Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations

Lecture 1. OUTLINE Basic Semiconductor Physics. Reading: Chapter 2.1. Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations Lecture 1 OUTLINE Basic Semiconductor Physics Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations Reading: Chapter 2.1 EE105 Fall 2007 Lecture 1, Slide 1 What is a Semiconductor? Low

More information

Three Most Important Topics (MIT) Today

Three Most Important Topics (MIT) Today Three Most Important Topics (MIT) Today Electrons in periodic potential Energy gap nearly free electron Bloch Theorem Energy gap tight binding Chapter 1 1 Electrons in Periodic Potential We now know the

More information

MTLE-6120: Advanced Electronic Properties of Materials. Intrinsic and extrinsic semiconductors. Reading: Kasap:

MTLE-6120: Advanced Electronic Properties of Materials. Intrinsic and extrinsic semiconductors. Reading: Kasap: MTLE-6120: Advanced Electronic Properties of Materials 1 Intrinsic and extrinsic semiconductors Reading: Kasap: 5.1-5.6 Band structure and conduction 2 Metals: partially filled band(s) i.e. bands cross

More information

Charge Carriers in Semiconductor

Charge Carriers in Semiconductor Charge Carriers in Semiconductor To understand PN junction s IV characteristics, it is important to understand charge carriers behavior in solids, how to modify carrier densities, and different mechanisms

More information

Chapter 12: Semiconductors

Chapter 12: Semiconductors Chapter 12: Semiconductors Bardeen & Shottky January 30, 2017 Contents 1 Band Structure 4 2 Charge Carrier Density in Intrinsic Semiconductors. 6 3 Doping of Semiconductors 12 4 Carrier Densities in Doped

More information

Lecture 2 Electrons and Holes in Semiconductors

Lecture 2 Electrons and Holes in Semiconductors EE 471: Transport Phenomena in Solid State Devices Spring 2018 Lecture 2 Electrons and Holes in Semiconductors Bryan Ackland Department of Electrical and Computer Engineering Stevens Institute of Technology

More information

Quiz #1 Practice Problem Set

Quiz #1 Practice Problem Set Name: Student Number: ELEC 3908 Physical Electronics Quiz #1 Practice Problem Set? Minutes January 22, 2016 - No aids except a non-programmable calculator - All questions must be answered - All questions

More information

EE143 Fall 2016 Microfabrication Technologies. Evolution of Devices

EE143 Fall 2016 Microfabrication Technologies. Evolution of Devices EE143 Fall 2016 Microfabrication Technologies Prof. Ming C. Wu wu@eecs.berkeley.edu 511 Sutardja Dai Hall (SDH) 1-1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) 1-2 1 Why

More information

CHAPTER 2: ENERGY BANDS & CARRIER CONCENTRATION IN THERMAL EQUILIBRIUM. M.N.A. Halif & S.N. Sabki

CHAPTER 2: ENERGY BANDS & CARRIER CONCENTRATION IN THERMAL EQUILIBRIUM. M.N.A. Halif & S.N. Sabki CHAPTER 2: ENERGY BANDS & CARRIER CONCENTRATION IN THERMAL EQUILIBRIUM OUTLINE 2.1 INTRODUCTION: 2.1.1 Semiconductor Materials 2.1.2 Basic Crystal Structure 2.1.3 Basic Crystal Growth technique 2.1.4 Valence

More information

Ch. 2: Energy Bands And Charge Carriers In Semiconductors

Ch. 2: Energy Bands And Charge Carriers In Semiconductors Ch. 2: Energy Bands And Charge Carriers In Semiconductors Discrete energy levels arise from balance of attraction force between electrons and nucleus and repulsion force between electrons each electron

More information

Basic Semiconductor Physics

Basic Semiconductor Physics 6 Basic Semiconductor Physics 6.1 Introduction With this chapter we start with the discussion of some important concepts from semiconductor physics, which are required to understand the operation of solar

More information

Semiconductor Devices and Circuits Fall Midterm Exam. Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering. Name: Mat. -Nr.

Semiconductor Devices and Circuits Fall Midterm Exam. Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering. Name: Mat. -Nr. Semiconductor Devices and Circuits Fall 2003 Midterm Exam Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering Name: Mat. -Nr.: Guidelines: Duration of the Midterm: 1 hour The exam is a closed

More information

Lecture 2. Semiconductor Physics. Sunday 4/10/2015 Semiconductor Physics 1-1

Lecture 2. Semiconductor Physics. Sunday 4/10/2015 Semiconductor Physics 1-1 Lecture 2 Semiconductor Physics Sunday 4/10/2015 Semiconductor Physics 1-1 Outline Intrinsic bond model: electrons and holes Charge carrier generation and recombination Intrinsic semiconductor Doping:

More information

n N D n p = n i p N A

n N D n p = n i p N A Summary of electron and hole concentration in semiconductors Intrinsic semiconductor: E G n kt i = pi = N e 2 0 Donor-doped semiconductor: n N D where N D is the concentration of donor impurity Acceptor-doped

More information

Variation of Energy Bands with Alloy Composition E

Variation of Energy Bands with Alloy Composition E Variation of Energy Bands with Alloy Composition E 3.0 E.8.6 L 0.3eV Al x GaAs AlAs 1- xas 1.43eV.16eV X k.4 L. X.0 X 1.8 L 1.6 1.4 0 0. 0.4 0.6 X 0.8 1 1 Carriers in intrinsic Semiconductors Ec 4º 1º

More information

Review of Semiconductor Fundamentals

Review of Semiconductor Fundamentals ECE 541/ME 541 Microelectronic Fabrication Techniques Review of Semiconductor Fundamentals Zheng Yang (ERF 3017, email: yangzhen@uic.edu) Page 1 Semiconductor A semiconductor is an almost insulating material,

More information

EECS143 Microfabrication Technology

EECS143 Microfabrication Technology EECS143 Microfabrication Technology Professor Ali Javey Introduction to Materials Lecture 1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) Why Semiconductors? Conductors e.g

More information

Semiconductor physics I. The Crystal Structure of Solids

Semiconductor physics I. The Crystal Structure of Solids Lecture 3 Semiconductor physics I The Crystal Structure of Solids 1 Semiconductor materials Types of solids Space lattices Atomic Bonding Imperfection and doping in SOLIDS 2 Semiconductor Semiconductors

More information

The Semiconductor in Equilibrium

The Semiconductor in Equilibrium Lecture 6 Semiconductor physics IV The Semiconductor in Equilibrium Equilibrium, or thermal equilibrium No external forces such as voltages, electric fields. Magnetic fields, or temperature gradients are

More information

Density of states for electrons and holes. Distribution function. Conduction and valence bands

Density of states for electrons and holes. Distribution function. Conduction and valence bands Intrinsic Semiconductors In the field of semiconductors electrons and holes are usually referred to as free carriers, or simply carriers, because it is these particles which are responsible for carrying

More information

ESE 372 / Spring 2013 / Lecture 5 Metal Oxide Semiconductor Field Effect Transistor

ESE 372 / Spring 2013 / Lecture 5 Metal Oxide Semiconductor Field Effect Transistor Metal Oxide Semiconductor Field Effect Transistor V G V G 1 Metal Oxide Semiconductor Field Effect Transistor We will need to understand how this current flows through Si What is electric current? 2 Back

More information

Intrinsic Semiconductors

Intrinsic Semiconductors Technische Universität Graz Institute of Solid State Physics Intrinsic Semiconductors ermi function f(e) is the probability that a state at energy E is occupied. f( E) 1 E E 1 exp kt B ermi energy The

More information

Numerical Example: Carrier Concentrations

Numerical Example: Carrier Concentrations 2 Numerical ample: Carrier Concentrations Donor concentration: N d = 10 15 cm -3 Thermal equilibrium electron concentration: n o N d = 10 15 cm 3 Thermal equilibrium hole concentration: 2 2 p o = n i no

More information

EE 346: Semiconductor Devices. 02/08/2017 Tewodros A. Zewde 1

EE 346: Semiconductor Devices. 02/08/2017 Tewodros A. Zewde 1 EE 346: Semiconductor Devices 02/08/2017 Tewodros A. Zewde 1 DOPANT ATOMS AND ENERGY LEVELS Without help the total number of carriers (electrons and holes) is limited to 2ni. For most materials, this is

More information

KATIHAL FİZİĞİ MNT-510

KATIHAL FİZİĞİ MNT-510 KATIHAL FİZİĞİ MNT-510 YARIİLETKENLER Kaynaklar: Katıhal Fiziği, Prof. Dr. Mustafa Dikici, Seçkin Yayıncılık Katıhal Fiziği, Şakir Aydoğan, Nobel Yayıncılık, Physics for Computer Science Students: With

More information

1 Name: Student number: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND. Fall :00-11:00

1 Name: Student number: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND. Fall :00-11:00 1 Name: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND Final Exam Physics 3000 December 11, 2012 Fall 2012 9:00-11:00 INSTRUCTIONS: 1. Answer all seven (7) questions.

More information

Calculating Band Structure

Calculating Band Structure Calculating Band Structure Nearly free electron Assume plane wave solution for electrons Weak potential V(x) Brillouin zone edge Tight binding method Electrons in local atomic states (bound states) Interatomic

More information

Lecture 7: Extrinsic semiconductors - Fermi level

Lecture 7: Extrinsic semiconductors - Fermi level Lecture 7: Extrinsic semiconductors - Fermi level Contents 1 Dopant materials 1 2 E F in extrinsic semiconductors 5 3 Temperature dependence of carrier concentration 6 3.1 Low temperature regime (T < T

More information

Semiconductor Junctions

Semiconductor Junctions 8 Semiconductor Junctions Almost all solar cells contain junctions between different materials of different doping. Since these junctions are crucial to the operation of the solar cell, we will discuss

More information

EE 346: Semiconductor Devices

EE 346: Semiconductor Devices EE 346: Semiconductor Devices Lecture - 6 02/06/2017 Tewodros A. Zewde 1 DENSTY OF STATES FUNCTON Since current is due to the flow of charge, an important step in the process is to determine the number

More information

Lecture 2 - Carrier Statistics in Equilibrium. September 5, 2002

Lecture 2 - Carrier Statistics in Equilibrium. September 5, 2002 6.720J/3.43J Integrated Microelectronic Devices Fall 2002 Lecture 21 Lecture 2 Carrier Statistics in Equilibrium Contents: September 5, 2002 1. Conduction and valence bands, bandgap, holes 2. Intrinsic

More information

Semiconductor Physics fall 2012 problems

Semiconductor Physics fall 2012 problems Semiconductor Physics fall 2012 problems 1. An n-type sample of silicon has a uniform density N D = 10 16 atoms cm -3 of arsenic, and a p-type silicon sample has N A = 10 15 atoms cm -3 of boron. For each

More information

Carriers Concentration in Semiconductors - V. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India

Carriers Concentration in Semiconductors - V. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India Carriers Concentration in Semiconductors - V 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/semi2013 Motion and Recombination of Electrons and

More information

L5: Surface Recombination, Continuity Equation & Extended Topics tanford University

L5: Surface Recombination, Continuity Equation & Extended Topics tanford University L5: Surface Recombination, Continuity Equation & Extended Topics EE 216 : Aneesh Nainani 1 Announcements Project Select topic by Jan 29 (Tuesday) 9 topics, maximum 4 students per topic Quiz Thursday (Jan

More information

A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced.

A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced. Semiconductor A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced. Page 2 Semiconductor materials Page 3 Energy levels

More information

ECE 606 Homework Week 7 Mark Lundstrom Purdue University (revised 2/25/13) e E i! E T

ECE 606 Homework Week 7 Mark Lundstrom Purdue University (revised 2/25/13) e E i! E T ECE 606 Homework Week 7 Mark Lundstrom Purdue University (revised 2/25/13) 1) Consider an n- type semiconductor for which the only states in the bandgap are donor levels (i.e. ( E T = E D ). Begin with

More information

Lecture 3b. Bonding Model and Dopants. Reading: (Cont d) Notes and Anderson 2 sections

Lecture 3b. Bonding Model and Dopants. Reading: (Cont d) Notes and Anderson 2 sections Lecture 3b Bonding Model and Dopants Reading: (Cont d) Notes and Anderson 2 sections 2.3-2.7 The need for more control over carrier concentration Without help the total number of carriers (electrons and

More information

FYS Vår 2014 (Kondenserte fasers fysikk)

FYS Vår 2014 (Kondenserte fasers fysikk) FYS3410 - Vår 014 (Kondenserte fasers fysikk) http://www.uio.no/studier/emner/matnat/fys/fys3410/v14/index.html Pensum: Solid State Physics by Philip Hofmann (Chapters 1-7 and 11) Andrej Kuznetsov delivery

More information

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006 UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EECS 130 Professor Ali Javey Fall 2006 Midterm I Name: Closed book. One sheet of notes is allowed.

More information

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. Professor Ali Javey. Spring 2009.

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. Professor Ali Javey. Spring 2009. UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EE143 Professor Ali Javey Spring 2009 Exam 1 Name: SID: Closed book. One sheet of notes is allowed.

More information

Minimal Update of Solid State Physics

Minimal Update of Solid State Physics Minimal Update of Solid State Physics It is expected that participants are acquainted with basics of solid state physics. Therefore here we will refresh only those aspects, which are absolutely necessary

More information

Solid State Device Fundamentals

Solid State Device Fundamentals Solid State Device Fundamentals ES 345 Lecture Course by Alexander M. Zaitsev alexander.zaitsev@csi.cuny.edu Tel: 718 982 2812 Oice 4101b 1 The ree electron model o metals The ree electron model o metals

More information

UConn ECE 4211, Semiconductor Devices and Nanostructures Lecture Week 1 January 17, 2017

UConn ECE 4211, Semiconductor Devices and Nanostructures Lecture Week 1 January 17, 2017 UConn ECE 411, Semiconductor Devices and Nanostructures Lecture Week 1 January 17, 017 Device Operation: One of the objectives of this course is to understand operation of carrier transport in semiconductor

More information

Electrons, Holes, and Defect ionization

Electrons, Holes, and Defect ionization Electrons, Holes, and Defect ionization The process of forming intrinsic electron-hole pairs is excitation a cross the band gap ( formation energy ). intrinsic electronic reaction : null e + h When electrons

More information

Note that it is traditional to draw the diagram for semiconductors rotated 90 degrees, i.e. the version on the right above.

Note that it is traditional to draw the diagram for semiconductors rotated 90 degrees, i.e. the version on the right above. 5 Semiconductors The nearly free electron model applies equally in the case where the Fermi level lies within a small band gap (semiconductors), as it does when the Fermi level lies within a band (metal)

More information

V BI. H. Föll: kiel.de/matwis/amat/semi_en/kap_2/backbone/r2_2_4.html. different electrochemical potentials (i.e.

V BI. H. Föll:  kiel.de/matwis/amat/semi_en/kap_2/backbone/r2_2_4.html. different electrochemical potentials (i.e. Consider the the band diagram for a homojunction, formed when two bits of the same type of semicondutor (e.g. Si) are doped p and ntype and then brought into contact. Electrons in the two bits have different

More information

Bohr s Model, Energy Bands, Electrons and Holes

Bohr s Model, Energy Bands, Electrons and Holes Dual Character of Material Particles Experimental physics before 1900 demonstrated that most of the physical phenomena can be explained by Newton's equation of motion of material particles or bodies and

More information

Chapter 2. Electronics I - Semiconductors

Chapter 2. Electronics I - Semiconductors Chapter 2 Electronics I - Semiconductors Fall 2017 talarico@gonzaga.edu 1 Charged Particles The operation of all electronic devices is based on controlling the flow of charged particles There are two type

More information

Chemistry Instrumental Analysis Lecture 8. Chem 4631

Chemistry Instrumental Analysis Lecture 8. Chem 4631 Chemistry 4631 Instrumental Analysis Lecture 8 UV to IR Components of Optical Basic components of spectroscopic instruments: stable source of radiant energy transparent container to hold sample device

More information

Section 12: Intro to Devices

Section 12: Intro to Devices Section 12: Intro to Devices Extensive reading materials on reserve, including Robert F. Pierret, Semiconductor Device Fundamentals Bond Model of Electrons and Holes Si Si Si Si Si Si Si Si Si Silicon

More information

ECE 250 Electronic Devices 1. Electronic Device Modeling

ECE 250 Electronic Devices 1. Electronic Device Modeling ECE 250 Electronic Devices 1 ECE 250 Electronic Device Modeling ECE 250 Electronic Devices 2 Introduction to Semiconductor Physics You should really take a semiconductor device physics course. We can only

More information

Electrical Resistance

Electrical Resistance Electrical Resistance I + V _ W Material with resistivity ρ t L Resistance R V I = L ρ Wt (Unit: ohms) where ρ is the electrical resistivity 1 Adding parts/billion to parts/thousand of dopants to pure

More information

smal band gap Saturday, April 9, 2011

smal band gap Saturday, April 9, 2011 small band gap upper (conduction) band empty small gap valence band filled 2s 2p 2s 2p hybrid (s+p)band 2p no gap 2s (depend on the crystallographic orientation) extrinsic semiconductor semi-metal electron

More information

Chapter 1 Overview of Semiconductor Materials and Physics

Chapter 1 Overview of Semiconductor Materials and Physics Chapter 1 Overview of Semiconductor Materials and Physics Professor Paul K. Chu Conductivity / Resistivity of Insulators, Semiconductors, and Conductors Semiconductor Elements Period II III IV V VI 2 B

More information

Engineering 2000 Chapter 8 Semiconductors. ENG2000: R.I. Hornsey Semi: 1

Engineering 2000 Chapter 8 Semiconductors. ENG2000: R.I. Hornsey Semi: 1 Engineering 2000 Chapter 8 Semiconductors ENG2000: R.I. Hornsey Semi: 1 Overview We need to know the electrical properties of Si To do this, we must also draw on some of the physical properties and we

More information

ELECTRONIC DEVICES AND CIRCUITS SUMMARY

ELECTRONIC DEVICES AND CIRCUITS SUMMARY ELECTRONIC DEVICES AND CIRCUITS SUMMARY Classification of Materials: Insulator: An insulator is a material that offers a very low level (or negligible) of conductivity when voltage is applied. Eg: Paper,

More information

Crystal Properties. MS415 Lec. 2. High performance, high current. ZnO. GaN

Crystal Properties. MS415 Lec. 2. High performance, high current. ZnO. GaN Crystal Properties Crystal Lattices: Periodic arrangement of atoms Repeated unit cells (solid-state) Stuffing atoms into unit cells Determine mechanical & electrical properties High performance, high current

More information

2. Point Defects. R. Krause-Rehberg

2. Point Defects. R. Krause-Rehberg R. Krause-Rehberg 2. Point Defects (F-center in NaCl) 2.1 Introduction 2.2 Classification 2.3 Notation 2.4 Examples 2.5 Peculiarities in Semiconductors 2.6 Determination of Structure and Concentration

More information

Mark Lundstrom 2/10/2013. SOLUTIONS: ECE 606 Homework Week 5 Mark Lundstrom Purdue University (corrected 3/26/13)

Mark Lundstrom 2/10/2013. SOLUTIONS: ECE 606 Homework Week 5 Mark Lundstrom Purdue University (corrected 3/26/13) SOLUIONS: ECE 606 Homework Week 5 Mark Lundstrom Purdue University corrected 6/13) Some of the problems below are taken/adapted from Chapter 4 in Advanced Semiconductor Fundamentals, nd. Ed. By R.F. Pierret.

More information

3. Semiconductor heterostructures and nanostructures

3. Semiconductor heterostructures and nanostructures 3. Semiconductor eterostructures and nanostructures We discussed before ow te periodicity of a crystal results in te formation of bands. or a 1D crystal, we obtained: a (x) x In 3D, te crystal lattices

More information

The Meaning of Fermi-Level And Related Concepts (Like Band-Bending)

The Meaning of Fermi-Level And Related Concepts (Like Band-Bending) The Meaning of Fermi-Level And Related Concepts (Like Band-Bending) Martin Peckerar January 14, 2003 The Fermi level is a term derived from statistical mechanics and used to calculate the number of mobile

More information

Semiconductor Physics. Lecture 3

Semiconductor Physics. Lecture 3 Semiconductor Physics Lecture 3 Intrinsic carrier density Intrinsic carrier density Law of mass action Valid also if we add an impurity which either donates extra electrons or holes the number of carriers

More information

A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL

A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL March 24, 2015 The University of Toledo, Department of

More information

Physics of Semiconductors. Exercises. The Evaluation of the Fermi Level in Semiconductors.

Physics of Semiconductors. Exercises. The Evaluation of the Fermi Level in Semiconductors. Physics of Semiconductors. Exercises. The Evaluation of the Fermi Level in Semiconductors. B.I.Lembrikov Department of Communication Engineering Holon Academic Institute of Technology I. Problem 8. The

More information

Chapter Two. Energy Bands and Effective Mass

Chapter Two. Energy Bands and Effective Mass Chapter Two Energy Bands and Effective Mass Energy Bands Formation At Low Temperature At Room Temperature Valence Band Insulators Metals Effective Mass Energy-Momentum Diagrams Direct and Indirect Semiconduction

More information

CME 300 Properties of Materials. ANSWERS: Homework 9 November 26, As atoms approach each other in the solid state the quantized energy states:

CME 300 Properties of Materials. ANSWERS: Homework 9 November 26, As atoms approach each other in the solid state the quantized energy states: CME 300 Properties of Materials ANSWERS: Homework 9 November 26, 2011 As atoms approach each other in the solid state the quantized energy states: are split. This splitting is associated with the wave

More information

Semiconductor device structures are traditionally divided into homojunction devices

Semiconductor device structures are traditionally divided into homojunction devices 0. Introduction: Semiconductor device structures are traditionally divided into homojunction devices (devices consisting of only one type of semiconductor material) and heterojunction devices (consisting

More information

The photovoltaic effect occurs in semiconductors where there are distinct valence and

The photovoltaic effect occurs in semiconductors where there are distinct valence and How a Photovoltaic Cell Works The photovoltaic effect occurs in semiconductors where there are distinct valence and conduction bands. (There are energies at which electrons can not exist within the solid)

More information

SEMICONDUCTOR PHYSICS

SEMICONDUCTOR PHYSICS SEMICONDUCTOR PHYSICS by Dibyendu Chowdhury Semiconductors The materials whose electrical conductivity lies between those of conductors and insulators, are known as semiconductors. Silicon Germanium Cadmium

More information

Classification of Solids

Classification of Solids Classification of Solids Classification by conductivity, which is related to the band structure: (Filled bands are shown dark; D(E) = Density of states) Class Electron Density Density of States D(E) Examples

More information

Electrical Characteristics of MOS Devices

Electrical Characteristics of MOS Devices Electrical Characteristics of MOS Devices The MOS Capacitor Voltage components Accumulation, Depletion, Inversion Modes Effect of channel bias and substrate bias Effect of gate oide charges Threshold-voltage

More information

PHYS208 p-n junction. January 15, 2010

PHYS208 p-n junction. January 15, 2010 1 PHYS208 p-n junction January 15, 2010 List of topics (1) Density of states Fermi-Dirac distribution Law of mass action Doped semiconductors Dopinglevel p-n-junctions 1 Intrinsic semiconductors List of

More information

Lecture 2 - Carrier Statistics in Equilibrium. February 8, 2007

Lecture 2 - Carrier Statistics in Equilibrium. February 8, 2007 6.720J/3.43J Integrated Microelectronic Devices Spring 2007 Lecture 21 Lecture 2 Carrier Statistics in Equilibrium Contents: February 8, 2007 1. Conduction and valence bands, bandgap, holes 2. Intrinsic

More information

Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. Intrinsic semiconductors:

Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. Intrinsic semiconductors: Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. There are two types of semi conductors. 1. Intrinsic semiconductors 2. Extrinsic semiconductors Intrinsic

More information

Direct and Indirect Semiconductor

Direct and Indirect Semiconductor Direct and Indirect Semiconductor Allowed values of energy can be plotted vs. the propagation constant, k. Since the periodicity of most lattices is different in various direction, the E-k diagram must

More information

ELEMENTARY BAND THEORY

ELEMENTARY BAND THEORY ELEMENTARY BAND THEORY PHYSICIST Solid state band Valence band, VB Conduction band, CB Fermi energy, E F Bloch orbital, delocalized n-doping p-doping Band gap, E g Direct band gap Indirect band gap Phonon

More information

Course overview. Me: Dr Luke Wilson. The course: Physics and applications of semiconductors. Office: E17 open door policy

Course overview. Me: Dr Luke Wilson. The course: Physics and applications of semiconductors. Office: E17 open door policy Course overview Me: Dr Luke Wilson Office: E17 open door policy email: luke.wilson@sheffield.ac.uk The course: Physics and applications of semiconductors 10 lectures aim is to allow time for at least one

More information

Chap. 11 Semiconductor Diodes

Chap. 11 Semiconductor Diodes Chap. 11 Semiconductor Diodes Semiconductor diodes provide the best resolution for energy measurements, silicon based devices are generally used for charged-particles, germanium for photons. Scintillators

More information

collisions of electrons. In semiconductor, in certain temperature ranges the conductivity increases rapidly by increasing temperature

collisions of electrons. In semiconductor, in certain temperature ranges the conductivity increases rapidly by increasing temperature 1.9. Temperature Dependence of Semiconductor Conductivity Such dependence is one most important in semiconductor. In metals, Conductivity decreases by increasing temperature due to greater frequency of

More information

Diamond. Covalent Insulators and Semiconductors. Silicon, Germanium, Gray Tin. Chem 462 September 24, 2004

Diamond. Covalent Insulators and Semiconductors. Silicon, Germanium, Gray Tin. Chem 462 September 24, 2004 Covalent Insulators and Chem 462 September 24, 2004 Diamond Pure sp 3 carbon All bonds staggered- ideal d(c-c) - 1.54 Å, like ethane Silicon, Germanium, Gray Tin Diamond structure Si and Ge: semiconductors

More information

Lecture 0. EE206 Electronics I

Lecture 0. EE206 Electronics I Lecture 0 Course Overview EE206 Electronics I Course description: Theory, characteristics and operation of diodes, bipolar junction transistors and MOSFET transistors. When: Tue Thu 10:30-12:20 (Lectures)

More information

PHYS208 P-N Junction. Olav Torheim. May 30, 2007

PHYS208 P-N Junction. Olav Torheim. May 30, 2007 1 PHYS208 P-N Junction Olav Torheim May 30, 2007 1 Intrinsic semiconductors The lower end of the conduction band is a parabola, just like in the quadratic free electron case (E = h2 k 2 2m ). The density

More information

Lecture 02 Semiconductor Physics

Lecture 02 Semiconductor Physics Lecture 02 Semiconductor Physics Prepared By Dr. Eng. Sherif Hekal Assistant Professor, CCE department Lecture 02 Semiconductors 10/15/201 7 1 ILOS In this section, we will learn: The basic properties

More information

ME 432 Fundamentals of Modern Photovoltaics. Discussion 15: Semiconductor Carrier Sta?s?cs 3 October 2018

ME 432 Fundamentals of Modern Photovoltaics. Discussion 15: Semiconductor Carrier Sta?s?cs 3 October 2018 ME 432 Fundamentals of Modern Photovoltaics Discussion 15: Semiconductor Carrier Sta?s?cs 3 October 2018 Fundamental concepts underlying PV conversion input solar spectrum light absorp?on carrier excita?on

More information

Key Questions. ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I 9/10/12. Class Outline: Effective Mass Intrinsic Material

Key Questions. ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I 9/10/12. Class Outline: Effective Mass Intrinsic Material 9/1/1 ECE 34 Lecture 6 : Intrinsic and Extrinsic Material I Class Outline: Things you should know when you leave Key Questions What is the physical meaning of the effective mass What does a negative effective

More information

ELECTRONIC I Lecture 1 Introduction to semiconductor. By Asst. Prof Dr. Jassim K. Hmood

ELECTRONIC I Lecture 1 Introduction to semiconductor. By Asst. Prof Dr. Jassim K. Hmood ELECTRONIC I Lecture 1 Introduction to semiconductor By Asst. Prof Dr. Jassim K. Hmood SOLID-STATE ELECTRONIC MATERIALS Electronic materials generally can be divided into three categories: insulators,

More information

3. Two-dimensional systems

3. Two-dimensional systems 3. Two-dimensional systems Image from IBM-Almaden 1 Introduction Type I: natural layered structures, e.g., graphite (with C nanostructures) Type II: artificial structures, heterojunctions Great technological

More information

ENERGY BANDS AND GAPS IN SEMICONDUCTOR. Muhammad Hafeez Javed

ENERGY BANDS AND GAPS IN SEMICONDUCTOR. Muhammad Hafeez Javed ENERGY BANDS AND GAPS IN SEMICONDUCTOR Muhammad Hafeez Javed www.rmhjaved.com rmhjaved@gmail.com Out Line Introduction Energy band Classification of materials Direct and indirect band gap of SC Classification

More information

EE301 Electronics I , Fall

EE301 Electronics I , Fall EE301 Electronics I 2018-2019, Fall 1. Introduction to Microelectronics (1 Week/3 Hrs.) Introduction, Historical Background, Basic Consepts 2. Rewiev of Semiconductors (1 Week/3 Hrs.) Semiconductor materials

More information

Carrier Statistics and State Distributions

Carrier Statistics and State Distributions Review 4 on Physical lectronics mportant Slide to watch without doing anything Carrier Statistics and State Distributions (Carriers, Fermi-Dirac Statistics in Solids, Fermi Level, Density of States, etc)

More information

A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL

A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL A. OTHER JUNCTIONS B. SEMICONDUCTOR HETEROJUNCTIONS -- MOLECULES AT INTERFACES: ORGANIC PHOTOVOLTAIC BULK HETEROJUNCTION DYE-SENSITIZED SOLAR CELL February 9 and 14, 2012 The University of Toledo, Department

More information

Lecture 15: Optoelectronic devices: Introduction

Lecture 15: Optoelectronic devices: Introduction Lecture 15: Optoelectronic devices: Introduction Contents 1 Optical absorption 1 1.1 Absorption coefficient....................... 2 2 Optical recombination 5 3 Recombination and carrier lifetime 6 3.1

More information

Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is

Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is CHAPTER 7 The PN Junction Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is uniformly doped with donor atoms.

More information

Diodes. anode. cathode. cut-off. Can be approximated by a piecewise-linear-like characteristic. Lecture 9-1

Diodes. anode. cathode. cut-off. Can be approximated by a piecewise-linear-like characteristic. Lecture 9-1 Diodes mplest nonlinear circuit element Basic operation sets the foundation for Bipolar Junction Transistors (BJTs) Also present in Field Effect Transistors (FETs) Ideal diode characteristic anode cathode

More information

The German University in Cairo. Faculty of Information Engineering & Technology Semiconductors (Elct 503) Electronics Department Fall 2014

The German University in Cairo. Faculty of Information Engineering & Technology Semiconductors (Elct 503) Electronics Department Fall 2014 The German University in Cairo th Electronics 5 Semester Faculty of Information Engineering & Technology Semiconductors (Elct 503) Electronics Department Fall 2014 Problem Set 3 1- a) Find the resistivity

More information