Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 1 doc
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
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15
• τ ~10
-1 4
sec for metals in
Drude model
Extracting Typical τ for Metals
© E.A. Fitzgerald -1 9 99
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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
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Predicting Conductivity using Drude
n
theory
from the periodic table...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 5 ppt
... 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...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 10 pps
... 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
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© H.L. Tuller-20 01
Microhotplate
7
4
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© 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...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 9 pps
... (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
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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...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 3 pot
...
First excited state 11 2, 211 , 12 1
• Ground state E ;
1
3 21
===
nnn
not zero!
© H.L. Tuller-20 01
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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...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps
... when you join these together?
© E. Fitzgerald -1 9 99
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-
-
+
+
+
+
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 (...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 8 pdf
... ;
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
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Dielectric Constant ... positions of
positive and negative ions
© E. Fitzgerald -1 9 99
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Ferroelectrics
Applications
• Capacitors
• Non-volatile memories
• Photoref...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 4 pps
... 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...
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
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© 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
)...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 2 pot
... 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
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11 ... E.A. Fitzgerald -1 9 99
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Success and Failure of Free e- Picture
• Success
– Metal conductivity
– Hall effect valence =1
– Skin Depth
– Wiedmann-Franz law
• Examples...
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