Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 1 doc

... Constant E gives ever-increasing v © E.A. Fitzgerald -1 9 99 4 3.225 15 • τ ~10 -1 4 sec for metals in Drude model Extracting Typical τ for Metals © E.A. Fitzgerald -1 9 99 3.225 16 Thermal Velocity ... current does a 10 0 W bulb draw? I = 10 0W /11 5V = 0.87A © H.L. Tuller-20 01 P = IV = V 3.225 14 Predicting Conductivity using Drude n theory from the periodic table...

Ngày tải lên: 11/08/2014, 14:20

... Eg =1. 1eV, and let µ e and µ h be approximately equal at 10 00cm 2 /V-sec (very good Si!). σ ~10 10 cm -3 *1. 602x10 -1 9 *10 00cm 2 /V-sec =1. 6x10 -6 S/m, or a resistivity ρ of about 10 6 ohm-m ... 10 18 cm -3 donors to Si: n~N d –n ~10 18 cm -3 , p ~10 2 (n i 2 /N d ) • Can change conductivity drastically – 1 part in 10 7 impurity in a...

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... 500 - 900 °C • Extrapolated room temperature conductivity: σ = 4.4 10 -1 8 S cm -1 8 9 10 11 12 13 10 -7 10 -6 10 -5 10 -4 Y-cut σ 0 = 2 .1 S cm -1 E A = 10 5 kJ mol -1 10 4 /T [1/ K] ... •Smart sensors 3.225 14 © H.L. Tuller-20 01 Microhotplate 7 4 3.225 7 © H.L. Tuller-20 01 0 5 10 15 20 25 30 35 1E-5 1E-4 1E-3 0, 01 0 ,1 T = 85...

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... (Ωcm) -1 ) T = 800 °C log(pO 2 / bar) 0.995 1, 005 -1 6 -4 0 -5 -4 -3 -2 -1 0 1 donor acceptor -2 0 -1 2 -8 donor doped acceptor doped 2 3.225 15 Designer Wavelengths Variation of ... High Acceptor Concentration in SrTiO 3 10 -2 0 10 -1 5 10 -1 0 10 -5 10 0 0 ,1 1 750°C 800°C 900°C 850°C 950°C electrical conductivit...

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... First excited state 11 2, 211 , 12 1 • Ground state E ; 1 3 21 === nnn not zero! © H.L. Tuller-20 01 3.225 24 Consequence of Electrons as Waves on Free Electron Model Standing wave picture Traveling ... Material m p m k E 22 222 == h E k ∆k=2π/L Quasi-continuous k m k E m k dk dE ∆=∆ = 2 2 h h states electrons E n E n -1 E n +1 m= +1/ 2 , -1 /2 All e- in box accounted fo...

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... when you join these together? © E. Fitzgerald -1 9 99 3.225 12 - - + + + + Holes diffuse Electrons diffuse + + + + - - - - + + + + - - + + + + An electric field forms due to ... 3.225 11 The p-n Junction (The Diode) • Note that dopants move the fermi energy from mid-gap towards either the valence band edge (p-type) or the conduction band edge (...

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... ; 1 ' ''' + − = + − += += nn n i so r Water molecule: τ=9.5x10 -1 1 sec, ω ~10 10 microwave oven, transmission of E-M waves logωτ -2 0 +2 ε’,ε’’ n 2 ε so α e +α i α e 3.225 20 Dielectric Constant ... positions of positive and negative ions © E. Fitzgerald -1 9 99 3.225 4 Ferroelectrics Applications • Capacitors • Non-volatile memories • Photoref...

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... numbers are:) n =1, 2,3,… =0 ,1, 2,…,n -1 m l =- , - +1, …,0,…, , (m s =+ or - 1/ 2) l l l l 0 -1 3.6eV U(r) © E. Fitzgerald -1 9 99 ) in -1 3.225 9 Diffraction Picture of the Origin of Band Gaps Probability ... MP and Eg increase while a o tends to decrease II B III IV V VI B NO Al Si P S Zn Ga Ge As Se Cd In Sn Sb Te MP ( ° K) Eg (eV) a o A 6 / 10 3.56 / 3...

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... material Material Type χ Paramagnetic +10 -5 -1 0 -4 Diamagnetic -1 0 -8 -1 0 -5 Ferromagnetic +10 5 2 5 3.225 5 © E. Fitzgerald -1 9 99 Microscopic Source of Magnetization • No monopoles • magnetic ... with difference mass loads. 0 10 0 200 300 400 500 600 700 800 1, 71 1, 72 1, 73 1, 74 1, 75 1, 76 1, 77 Contact 1 (f Co1 ) Contact 2 (f Co2 )...

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... cos(kx-ωt), and e -i(kx-ωt) are all waves e -i(kx-ωt) is the complex one and is the most general real imaginary A Acosθ iAsinθ θ e iθ =cosθ+isinθ © E.A. Fitzgerald -1 9 99 1 3.225 11 ... E.A. Fitzgerald -1 9 99 3.225 10 Success and Failure of Free e- Picture • Success – Metal conductivity – Hall effect valence =1 – Skin Depth – Wiedmann-Franz law • Examples...

Ngày tải lên: 11/08/2014, 14:20