Pdf 2573 dq dt electric field 2013 02 15 104727 vd

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Unformatted text preview: 013-02-15 10:47:27 25/73 Chapter 18.pdf (25/73) • – – – • – dQ dt Electric field • 2013-02-15 10:47:27 vd 26/73 e E Chapter 18.pdf (26/73) • • – – – 2013-02-15 10:47:27 27/73 Chapter 18.pdf (27/73) 22 2013-02-15 10:47:28 28/73 Chapter 18.pdf (28/73) • t 2013-02-15 10:47:28 0 aT 29/73 Chapter 18.pdf (29/73) • As T , n ... • … but e and this dominates when it comes to temperature dependence. • The net result: E 0K aT T>0 K EF EF for T > 200oC N(E) 24 2013-02-15 10:47:28 30/73 Chapter 18.pdf (30/73) • • – i Ac i (1 ci ) Room temperature electrical resistivity versus composition for copper nickel alloys 2013-02-15 10:47:28 31/73 Chapter 18.pdf (31/73) total 2013-02-15 10:47:29 t 32/73 i d Chapter 18.pdf (32/73) Ag > Cu 2 Al • – • – • – 27 2013-02-15 10:47:29 33/73 Chapter 18.pdf (33/73) Part III: Conduction in Semiconductors 2013-02-15 10:47:29 34/73 Chapter 18.pdf (34/73) • – – • – – 2013-02-15 10:47:29 35/73 Chapter 18.pdf (35/73) • – – – 2013-02-15 10:47:30 36/73 Chapter 18.pdf (36/73) • ) 31 2013-02-15 10:47:30 37/73 Chapter 18.pdf (37/73) • • • • – • – 2013-02-15 10:47:30 38/73 Chapter 18.pdf (38/73) • – – • n|e| p|e| e h • n|e|( 2013-02-15 10:47:31 39/73 e h ) Chapter 18.pdf (39/73) Pure Si - no excitation Pure Si - after excitation 34 2013-02-15 10:47:31 Pure Si - after excitation electrons and holes move in response to the electric field 40/73 Chapter 18.pdf (40/73) • • – – n p e 1.33 1016 / m 3 e h – Note: here represents the atomic volume 35 2013-02-15 10:47:31 41/73 Chapter 18.pdf (41/73) • – • – • – – • 36 2013-02-15 10:47:31 42/73 Chapter 18.pdf (42/73) • Excess electrons are loosely bound (weak electrostatic attraction) therefore easy to promote to conduction band • electron binding energy corresponds to the energy required to excite the electron from an impurity state to a state within the conduction band (ED) • Excess...
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This note was uploaded on 03/24/2013 for the course ENGINEER 101 taught by Professor Preston during the Winter '13 term at McMaster University.

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