Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 5 ppt

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

... Tuller-2001 For R9 3.2 25 9 Equation of Motion - Impact of Collisions Assume: • probability of collision in time dt = dt/τ • time varying field F(t) v(t+dt) = ( 1- dt/τ) {v(t) +dv} = ( 1- dt/τ) ... wave-like • activated hopping • Field Dependence: • Linear vs non-linear © H.L. Tuller-2001 varies by over 25 orders of m1 3.2 25 7 Microscopic Origin: Can we Predict Conductivity of Metals? ... Constant E gives ever-increasing v © E.A. Fitzgerald-1999 4 3.2 25 15 • τ~10 -1 4 sec for metals in Drude model Extracting Typical τ for Metals © E.A. Fitzgerald-1999 3.2 25 16 Thermal Velocity...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 5 ppt

... –1022*1/107=10 15 dopant atoms per cm -3 –n~10 15 , p~1020/10 15 ~10 5 σ/σi~(p+n)/2ni~n/2ni~10 5 ! Impurities at the ppm level drastically change the conductivity ( 5- 6 orders of magnitude) ... Eg=1.1eV, and let µe and µh be approximately equal at 1000cm2/V-sec (very good Si!). σ~1010cm -3 *1.602x10 -1 9*1000cm2/V-sec=1.6x10 -6 S/m, or a resistivity ρ of about 106 ohm-m max. ... Fitzgerald-1999 ) 7 3.2 25 11 Density of Thermally Promoted of Carriers ∫ ∞ = cE dEEgEfn )()( Density of electron states per volume per dE Fraction of states occupied at a particular...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 10 pps

... 13 10 -7 10 -6 10 -5 10 -4 Y-cut σ0 = 2.1 S cm -1 EA = 1 05 kJ mol -1 104/T [1/K] σ [S cm -1 ] 900 800 700 600 50 0 T [°C] 13 3.2 25 13© H.L. Tuller-2001 Gas Sensors and MEMS ... •Smart sensors 3.2 25 14© H.L. Tuller-2001 Microhotplate 7 43.2 25 7© H.L. Tuller-20010 5 10 15 20 25 30 35 1E -5 1E-41E-30,010,1T = 850 °CX=0.03X=0.03Sr1-xLaxTiO3 porous ... Electro-chemical Etching - PEC • Electro-chemical etching p-type + - Light source • Photo electro-chemical etching + - h+h+semiconductor electrolyte Light source n-type 3.2 25 20©...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 9 pps

... (Ωcm) -1 ) T = 800 °C log(pO2 / bar) 0.9 95 1,0 05 -1 6 -4 0 -5 -4 -3 -2 -1 0 1 donoracceptor -2 0 -1 2 -8 donor dopedacceptor doped 2 3.2 25 15 Designer Wavelengths Variation of ... Electromechanical •Optical •Magnetic 10 3.2 25 5 © H.L. Tuller-2001 Temperature Independence: High Acceptor Concentration in SrTiO3 10 -2 0 10 -1 5 10 -1 0 10 -5 100 0,1 1 750 °C 800°C ... Wavelengths Variation of band-gap energy with composition x of In1-xGaxAs. © H.L. Tuller, 2001 3.2 25 16 Band-Gap Colors Mixed crystals of yellow cadmium sulfide CdS and black cadmium selenide...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 3 pot

... 3.2 25 15 • Compton, Planck, Einstein – light (xrays) can be ‘particle-like’ • DeBroglie – matter can act like it has a ‘wave-nature’ • Schrodinger, Born – Unification of wave-particle ... Fitzgerald-1999 )))33.2 25 5Effect of Temperature (T>0): Coupled electronic- thermal properties in conductors• Electrons at the Fermi surface are able to increase energy: responsible for properties • ... are λ=h/p~10 -8 cm in size • Certain wavelengths of valence electrons will diffract! © E. Fitzgerald-1999 3.2 25 8 Diffraction Picture of the Origin of Band Gaps • Start with 1-D crystal...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps

... when you join these together? © E. Fitzgerald-1999 3.2 25 12 - - ++ + + Holes diffuse Electrons diffuse ++ + + - - - - ++ + + - - ++ + + An electric field forms due to ... 3.2 25 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 (n-type). p-type ... cavityJhdiff © E. Fitzgerald-1999 Potential Wells - Heterojunction Lasers Energy bands of a light-emitting diode under forward bias for a double heterojunction AlGaAs-GaAs-AlGaAs structure. © H.L....

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 8 pdf

... Fitzgerald-1999 9 3.2 25 11 Interaction of the d orbitals of a central ion with six ligands in an octahedral arrangement. Octahedral Environment of Transition Metal Ion © H.L. Tuller, 2001 3.2 25 ... H.L. Tuller, 2001 W6 3.2 25 7 Characteristics of Optical Fiber © E. Fitzgerald-1999 3.2 25 8 Characteristics of Optical Fiber © E. Fitzgerald-1999 4 3.2 25 3 Ferroelectrics • ‘Confused’ ... metastable relative positions of positive and negative ions © E. Fitzgerald-1999 3.2 25 4 Ferroelectrics Applications • Capacitors • Non-volatile memories • Photorefractive materials © H.L. Tuller,...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 4 pps

... 151 0 / ? 0.72 / 1. 35/ ? 5. 66 / 5. 65 / ? 50 8 / 798 / ? 0.08 /0.18 / 1. 45 6. 45 / 6.09 / ?IV / III-V / II-VI*∗ Fill in as many of the question marks as you can.C83.2 25 15 Real Band Structures• ... are:)n=1,2,3,…=0,1,2,…,n-1ml =- , - +1,…,0,…, , (ms=+ or - 1/2)llll0 -1 3.6eVU(r)© E. Fitzgerald-1999)in -1 3.2 25 9 Diffraction Picture of the Origin of Band Gaps Probability Density=probability/volume ... Electron Model © E. Fitzgerald-1999 5 3.2 25 5 Metals and Insulators •EF in mid-band area: free e-, metallic •EF near band edge –EF in or near kT of band edge: semimetal –EF in...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 11 potx

... material Material Type χ Paramagnetic +10 -5 -1 0 -4 Diamagnetic -1 0 -8 -1 0 -5 Ferromagnetic +10 5 2 5 3.2 25 5 © E. Fitzgerald-1999 Microscopic Source of Magnetization • No monopoles • magnetic ... negativeRule of Thumb: 5. 1radius) 2(atomicdistance cinteratomi2>≡arrJ is a function of distance!83.2 25 8© E. Fitzgerald-1999FerromagnetismMTTC() ( )() ( )1. 4-1 .3 0.3 7-0 .33 ≈−∝≈−∝−γχβγβTTTTTTMCCHB=H+4πM‘normal’ ... µr = B/ µ0H = 1 + (M/H) = 1 + χm Magnetic Permeability and Susceptibility 4 3.2 25 4© E. Fitzgerald-1999 Maxwell and Magnetic Materials • Ampere’s law • For a permanent magnet, there...

Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 2 pot

... 7 .5 x 1014 Hz) λ = c/ν = 400 nm k=2π/ λ = 1 .57 x 107 m -1 ω = 2 πν = 4.71 x 10 15 s -1 After Livingston ε) ε(kx-) ε6 3.2 25 23 • Scaling of Si CMOS includes conductivity engineering ... e-i(kx-ωt) are all waves e -i(kx-ωt) is the complex one and is the most general real imaginary A Acosθ iAsinθθ e iθ=cosθ+isinθ © E.A. Fitzgerald-1999 1 3.2 25 11 Wiedmann-Franz ... Fitzgerald-1999 5 3.2 25 25 Experimental Hall Results on Metals • Valence=1 metals look like free-electron Drude metals • Valence=2 and 3, magnitude and sign suggest problems © E.A. Fitzgerald-1999...

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