3/27/2015 - PowerPoint Presentation

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3/27/2015

PHY 752 Spring 2015 -- Lecture 25

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PHY 752 Solid State Physics11-11:50 AM MWF Olin 107Plan for Lecture 25:Chap. 18 & 19 in MarderImpurity statesProperties of semiconductors

Some of the lecture materials are from slides prepared by

MarderSlide2

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PHY 752 Spring 2015 -- Lecture 25

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PHY 752 Spring 2015 -- Lecture 25

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Impurity states due to point defectsSlide4

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PHY 752 Spring 2015 -- Lecture 25

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Impurity states due to point defects -- continuedSlide5

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PHY 752 Spring 2015 -- Lecture 25

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Impurity states due to point defects -- continuedDielectric constant

valence charge of impurity relative to that of host latticeSlide6

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PHY 752 Spring 2015 -- Lecture 25

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Impurity states due to point defects -- continuedSlide7

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor propertiesPopulation of electrons (n) and holes (p) in a pure semiconductormSlide8

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties -- continuedFor:Slide9

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties -- continuedmultiplicity of conduction band minimaSlide10

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties -- continuedFor intrinsic semiconductor, n=p=niSlide11

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties -- continuedEffects of impurities:Intrinsic carriers:Slide12

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties – continuedTypically, the ionized impurities dominate the carrier concentrationsSlide13

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor properties – continuedFor primarily donor doping:For primarily acceptor doping:Slide14

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor junctionBefore equilibrationAfter equilibrationJunction potentialSlide15

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor junctionSlide16

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor junctionSlide17

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PHY 752 Spring 2015 -- Lecture 25

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Simplified model:Semiconductor junctionSlide18

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PHY 752 Spring 2015 -- Lecture 25

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Semiconductor junctionSlide19

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PHY 752 Spring 2015 -- Lecture 25

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Behavior of ideal diodeSlide20

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PHY 752 Spring 2015 -- Lecture 25

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Behavior of ideal diode – continued Diffusion of electrons and holes: