Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 1 doc
... Tuller-2001
For R
9
3.225
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) ... L/Wt = ρ L/A ⇒ρ(οhm-cm)
σ = 1/ρ ⇒ σ (οhm-cm)
-1
⇒σ (Siemens/cm)
(Test your dimensions: σ=E/j=neµ)
Ohms/square ⇒ Note, if L=W, then R= ρ /t independent
of magnitude...
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 1000cm
2
/V-sec (very good Si!).
σ~10
10
cm
-3
*1 .60 2x10
-1 9
*1000cm
2
/V-sec=1.6x10
-6
S/m, or a resistivity ρ of about 10
6
ohm-m max. ... Fitzgerald-1999
)
7
3.225
11
Density of Thermally Promoted of Carriers
∫
∞
=
c
E
dEEgEfn
)()(
Density of electron states per volume per dE
Fraction of s...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 10 pps
... 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
= 105 kJ mol
-1
10
4
/T [1/K]
σ
[S cm
-1
]
900 800 700 60 0 500
T [°C]
13 ... Tuller-2001
+
-
+
-
h
+
h
+
h
+
h
+
semiconductor
Photo Electro-chemical Etching - PEC
• Electro-chemical
etching
p-type
+
-
Light source
•...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 9 pps
... 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 band-gap energy with composition x of In
1-x
Ga
x
As. ...
900 6. 5
800 26
750 83
700
[1] Menesklou et al, MRS fall
meeting, Vol. 60 4, p. 30 5-1 0 (1999).
185
3.225
6
© H.L. Tuller-2001
Oxygen Sensor...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 3 pot
... (xrays) can be ‘particle-like’
• DeBroglie
– matter can act like it has a ‘wave-nature’
• Schrodinger, Born
– Unification of wave-particle duality, Schrodinger
Equation
Wave-particle Duality: ... E. Fitzgerald-1999
3.225
18
Ψ must be able to represent everything from a particle to a wave (the two
extremes)
Unification: Wave-particle Duality
wave
particle
(
tkxi
Ae
ω−
=Ψ
k and p kn...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps
... when you join these together?
© E. Fitzgerald-1999
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 (n-t...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 8 pdf
...
−
=
1
© E. Fitzgerald-1999
9
3.225
11
Interaction of the d orbitals of a central ion with six ligands in
an octahedral arrangement.
Octahedral Environment of Transition Metal Ion
© ...
The splitting of the five 3d orbitals in a tetrahedral and an octahedral ligand field.
Note: hen the element is a mid-gap dopant, transitions within this element lead to
absorption and/...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 4 pps
... 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-1999
)
in
-1
3.225
9
Diffraction Picture of the Origin of Band Gaps
Probability Density=probability/volume ... ? 0.72 / 1.35/ ? 5 .66 / 5 .65 / ?
508 / 798 / ? 0.08 /0.18 / 1.45 6. 45 / 6. 09 / ?
IV / III-V / II-VI*
∗ Fill in as many of the question mark...
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
3.225
5
© E. Fitzgerald-1999
Microscopic Source of Magnetization
• No monopoles
• magnetic ... 2(atomic
distance cinteratomi
2
>≡
a
r
r
J is a function of distance!
8
3.225
8
© E. Fitzgerald-1999
Ferromagnetism
M
T
T
C
() ( )
() ( )
1. 4-1 .3
0.3...
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 2 pot
... 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-1999
1
3.225
11
Wiedmann-Franz ... out of phase with E
ω<<1/τ, p in phase with E
ω
i
eE
p
0
0
=
0,
→∞→
pω
τ
00
eEp
=
© E.A. Fitzgerald-1999
3.225
2
Complex Representation of Waves
sin(kx-ωt), cos(kx-ωt...
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