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Electronic Materials and
Devices to use these slides in
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Fig 4.1
From Principles of Electronic Materials and Devices, Third Edition, S.O. Kasap (© McGraw-Hill, 2005)
Formation of molecular orbitals, bonding and antibonding (  and  ) when
two H atoms approach each other. The two electrons pair their spins and occupy
the bonding orbital .
r
 = 1s(rA) + 1s(rB)
* = 1s(rA) - 1s(rB)
Bonding Molecular Orbital
Antibonding Molecular Orbital
a
r
H
r
R = 
A B
Two hydrogen atoms approaching each other.
1s(rA) 1s(rB)
H
rA
e-
rB
e-

Fig 4.2
(b)
(a) 

H H


H H
(a) Electron probability distributions for bonding and antibonding orbitals, 
and *. (b) Lines represent contors of constant probability.

Fig 4.3
Electron energy in the system comprising two hydrogen atoms. (a) Energy of
 and  vs. the interatomic separation, R. (b) Schematic diagram
showing the changes in the electron energy as two isolated H atoms, far left
and far right, come to form a hydrogen molecule.
H -atom H -atom
H2
E
E
E = Bonding Energy
E1s
E1s
(b)

E(R)
1s
E1s

E
(a)
E
(R)
0
E
SYSTEM
2 H-Atoms
2 Electrons
1 Electron/Atom
1 Orbital/Atom
R, Interatomic
Separation
0 R = 
Bonding
Energy
(a)
a

Fig 4.4
i( )

(a)
R C
L
i()
v()
 0

 1
 2
(b)
R C
L L
C
R
M
Coupling
i( )
i()
There is one resonant frequency, 0, in an isolated LCR circuit. (b) There are
two resonant frequencies in two coupled LCR circuits. One below and the
other above 0.

Fig 4.5
E1s
E
E
E1s
He-atom He-atom
He-He
System
Two He atoms have 4 electrons. When He atoms come together 2 of the
electrons enter the E and 2 the E levels so that the overall energy is
greater than two isolated He atoms.

Fig 4.6
H has one half empty 1s orbital. F has one half empty px orbital but full py
and pz orbitals. The overlap between 1s and px produces a bonding orbital
and an antibonding orbital. The two electrons fill the bonding orbital and
thereby form a covalent bond between H and F.
H
Half-Full 1s
1s
Full py
py
Half-Full px
px
pz
Full pz
px
F H-F
1s
px
Bonding Orbital, 
py
pz
px

Fig 4.7
(a) Three molecular orbitals from three 1s atomic orbitals overlapping
in three different ways. (b) The energies of the three molecular orbitals
labeled as a, b and c in a system with 3 H atoms (highly simplified).
a
A B C
b
c
E
Ec
E1s
a
b
c
Separation
Eb
Ea
R = 
R = a
c
a
b
System
in isolation
3 H-Atoms
3 Electrons
3 Orbitals (1s)
6 States (with spin)
Symmetric
(b)
(a)
Symmetric
Antisymmetric

Fig 4.8
The formation of a 2s-energy band from the 2s-orbitals when N Li atoms
come together to form the Li solid. The are N 2s-electrons but 2N states in
the band. The 2s-band therefore is only half full. The atomic 1s orbital is
close to the Li nucleus and remains undisturbed in the solid. Thus each Li
atom has a closed K-shell (full 1s orbital).
a
Interatomic
Separation (R)
SYSTEM
N Li Atoms
N Electrons
N Orbitals
2N States
E2p
1s
2s
2p

E2s
E1s
System of N Li Atoms
solid(N)
Solid
ET
EB solid(1)
Isolated Atoms
FULL
EMPTY
Electron
Energy
in
the
System
of
N
Li
Atoms

Fig 4.9
As solid atoms are brought together from infinity, the atomic orbitals
overlap and give rise to bands. Outer orbitals overlap first. The 3s
orbitals give rise to the 3s band, 2p orbitals to the 2p band and so on.
The various bands overlap to produce a single band in which the energy
is nearly continuous.
Interatomic
Separation (R)
E2s
E2p
E3s
E1s
R = a R = 
Isolated Atoms
The Solid
E = 0 (Vacuum Level)
Free electron
FULL
EMPTY
Electron
energy

Fig 4.10
In a metal the various energy bands overlap to give a single band of
energies that is only partially full of electrons. There are states with
energies up to the vacuum level where the electron is free.
2s
2p
3s
Overlapping
energy bands
Electrons
Vacuum level
2s
2p
3s
3p
1s
1s
Solid Atom
E = 0
Free electron
E
E
lectron
E
nergy

Fig 4.11
Typical electron energy band diagram for a metal All the valence electrons
are in an energy band which they only partially fill. The top of the band is
the vacuum level where the electron is free from the solid (PE = 0).
Electron Energy
Vacuum
Level
EF0
EB
EF0

Electron inside the
metal
Electron outside
the metal
0
-2.5 eV
-7.2 eV 0
4.7 eV
7.2 eV

Fig 4.12
Electrons
Empty states
0
(a)
E
px
-x x
p-x
a
pav
= 0
b
(b)
Lattice
scattering
pav
> 0
E
E
px
p-x
E
a
b
(c)
FO
FO
(a) Energy band diagram of a metal. (b) In the absence of a field, there are as many
electrons moving right as there are moving left. The motions of two electrons at each
energy cancel each other as for a and b. (c) In the presence of a field in the x direction,
the electron a accelerates and gains energy to a’ where it is scattered to an empty state
near EFO but moving in the -x direction. The average of all momenta values is along the
+x direction and results in a net electrical current.

Fig 4.13
Conduction in a metal is due to the drift of electrons around the Fermi
level. When a voltage is applied, the energy band is bent to be lower at the
positive terminal so that the electron's potential energy decreases as it
moves towards the positive terminal.
Energy band diagram
Electrons
Empty levels
x
V(x)
V
x
EFO
EB
EFO - eV
EB - eV

Fig 4.14
Liquid metallic hydrogen
(with helium)
Molecular hydrogen and
helium
Possible rocky core
Cloud tops (the atmospheric layer is
comparatively thin compared with
Jupiter's size)
The interior of Jupiter is believed to contain liquid hydrogen which is
metallic (drawing adapted from T. Hey and P. Walters, The Quantum
Universe, Cambridge University Press, 1988; Fig. 7.1, p. 96)

Fig 4.15
3p
3s
2p
2s
1s
Electron
Energy
The electronic structure of Si.

Fig 4.16
(a). Si is in Group IV in the Periodic Table. An isolated Si atom has 2 electrons in the 3s and
2 electrons in the 3p orbitals. (b) When Si is about to bond, the one 3s-orbital and the three
3p-orbitals become perturbed and mixed to form four hybridized orbitals, hyb, called sp3
orbitals which are directed towards the corners of a tetrahedron. The hyb orbital has a large
major lobe and a small back lobe. Each hyb orbital takes one of the four valence electrons.

Fig 4.17
(a) Formation of energy bands in the Si crystal first involves hybridization of 3s and 3p orbitals to four
identical hyb orbitals which make 109.5
o
with each other as shown in (b). (c) hyb orbitals on two
neighboring Si atoms can overlap to form B or A. The first is a bonding orbital (full) and the second is an
antibondiong orbital (empty). In the crystal yB overlap to give the valence band (full) and A overlap to give
the conduction band (empty).
hyb
Si ATOM
B
B
A
A
CONDUCTION BAND
VALENCE BAND
Energy gap, Eg
(a) (b) (c) (d)
3p
3s
Si CRYSTAL
hyb

Fig 4.18
Energy band diagram of a semiconductor. CB is the conduction band and
VB is the valence band. At 0 K, the VB is full with all the valence
electrons.
Ec
Ev
CB
VB
Eg
Thermal
excitation
Electron
energy

Fig 4.19
e-
Fext
VACUUM
x
Fext
me
a =
(a)
Ex
Fint
CRYSTAL
x
Fext
me
*
a =
(b)
(a) An external force Fext applied to an electron in vacuum results in an
acceleration avac = Fext / me . (b) An external force Fext applied to an
electron in a crystal results in an acceleration acryst = Fext / me*. ( Ex is the
electric field.)
Ex

Fig 4.20
(a) In the solid there are N atoms and N extended electron wavefunctions
from 1 all the way to N . There are many wavefunctions, states, that
have energies that fall in the central regions of the energy band. (b) The
distribution of states in the energy band; darker regions have higher
number of states. (c) Schematic representation of the density of states
g(E) vs. energy E.
1
(a)
N
Energy Band
(b) (c)
E
g(E)

Fig 4.21
n1
2
+ n2
2
= n'
2
n1
= 1
n2
= 3
0
1
2
3
4
5
1 2 3 4 5 6
n1
= 2, n2
= 2
Each state, electron wavefunction in the crystal, can be represented
by a box at n1,n2.
n2
-n2
n1
-n1

Fig 4.22
n2
In here n1
2
+n2
2
+n3
2
 n'2
n'
Vol. = 1/8(4/3 n'3
)
n3
n1
In three dimensions, the volume defined by a sphere of radius n' and the
positive axes n1, n2 and n3, is all the possible combinations of poisitive
n1, n2 and n3, values which satisfy n1
2+n2
2+n3
2  n'2.

Fig 4.23
(a) High energy electron bombardment knocks out an electron from the closed inner L-shell leaving an empty state. An
electron from the energy band of the metal drops into the L-shell to fill the vacancy and emits a soft X-ray photon in the
process. (b) The spectrum (intensity vs photon energy) of soft X-ray emission from a metal involves a range of energies
corresponding to transitions from the bottom of the band and from the Fermi level to the L-shell. The intensity increases with
energy until around EF where it drops sharply. (c) and (d) contrast the emission spectra from a solid and vapor (isolated gas
atoms).
24 22 20 18 16
80
70
60
50
80
70
60
50
Intensity of
emitted X-rays
from Al
Energy (eV)
Energy (eV)
Wavelength (nm)
Vapor
Solid
(b)
(c)
(d)
Energy
Band
X-ray photon
Ejected electron
Inner Shell
(a)
High energy
electron
bombardment
EB
EF
EL
-shell

Fig 4.24
E1
2
1
E2
E4
E3
4
3
Interaction
Two electrons initially with wavefunctions  1 and  2 at E1 and E2
interact and end up at different energies at E3 and E4. Their
corresponding wavefunctions are  3 and  4.

Fig 4.25
 exp(-E/kT)
N1
N2
N(E)
E
E2
E1
0
The Boltzmann energy distribution describes the statistics of particles,
e.g. electrons, when the particles do not interact with each other, i.e.
when there are very few electrons compared with the number of
available states.

Fig 4.26
E
EF
0 1
/
2
1
f(E)
T1
T = 0
T2
> T1
The Fermi-Dirac function, f(E), describes the statistics of electrons
in a solid. The electrons interact with each other and the
environment so that they obey the Pauili Exclusion Principle.

Fig 4.27
(a ) Abov e 0 K, due to ther m
a l excita tion, s om
e of the el ectr ons
a r e a t ener gies a bov e EF . (b) The dens ity of s ta tes , g(E) v s E
in the ba nd. (c) The pr oba bil ity of occupa ncy of a s ta te a t a n
ener gy E is f (E). The pr oduct g(E)f (E) is the num
ber of
el ectr ons per unit ener gy per unit v ol um
e or el ectr on
concentr a tion per unit ener gy. The a r ea under the cur v e with
the ener gy a xis is the concentr a tion of el ectr ons in the ba nd.
E
0 1/2
1 f(E)
T K
E E
g(E)
g(E) = A E1/2
nE
= g(E)f (E)
EF
EF
+ 
E
0
(a) (b) (c) (d)
n
dE
nE



0
EF

Fig 4.28
When two metals are brought together, there is a contact potential, V.
(a) Electrons are more energetic in Mo so they tunnel to the surface of Pt.
(b) Equilibrium is reached when the Fermi levels are lined up.
5.36
eV
4.20
eV
Fermi level
(Pt) - (Mo) = 1.16 eV = eV
Vacuum
Vacuum
Fermi level
Pt Mo
Vacuum
Fermi level
Vacuum
(b)
(a)
(P
t)
=
5.36
eV

(M
o)
=
4.20
eV
Electrons
Electrons

Fig 4.29
Mo Pt
Mo Pt
1.1V
1.1V
I = 0
There is no current when a closed circuit is formed from two
different metals, even though there is a contact potential at each
contact. The contact potentials oppose each other.

Fig 4.30

Fig 4.31
H C
Energy
x
(a) S positive
 
H C
Energy
x
(a) S negative


Consider two neighboring regions H (hot) and C (cold) with widths
corresponding to the mean free paths  and  in H and C. Half the
electrons in H would be moving in +x direction and the other half
in x direction. Half of the electrons in H therefore cross into C,
and half in C cross into H.

Fig 4.32
(a) If same metal wires are used to measure the Seebeck voltage across the
metal rod, then the net emf is zero. (b)The thermocouple from two different
metals, type A and B. The cold end is maintained at 0 ¡C which is the
reference temperature. The other junction is used to sense the temperature. In
this example it is heated to 100 ¡C.
Metal
100
o
C
Cold
Hot
V
0
Metal
Metal
0
o
C
(a)
Cold
Hot
V
0
Metal
type B
Metal
type B
Metal
type A
(b)
100
o
C 0
o
C

Thermocoples are widely used to measure the
temperature.
LEFT: A thermocouple pair embedded in a
stainless steel sheath-probe. The thermocouple
junction inside the probe is in thermal contact
with the probe tip, and, electrically insulated
from the probe metal.
|SOURCE: Courtesy of Omega

0
10
20
30
40
50
60
70
80
0 200 400 600 800 1000
Temperature (oC)
E-Type
J-Type
S-Type
T-Type
K-Type
Output emf vs temperature (oC) for various termocouples between 0
to 1000oC.
EMF (mV)

Examples of vacuum Tubes Using Thermionic Emission
LEFT: Klystrons are used as the
final amplifier stage in many
UHF television transmitters.
|SOURCE: Courtesy of Thales
TOP: UHF Tetrode vacuum tubes that can
handle up to 30 kW, and provide gains up to
17 dB
|SOURCE: Courtesy of Thales

Fig 4.34
Cathode
Filament
I
Vacuum
Plate or Anode
(a)
I
V
Saturation current
(b)
(a) Thermionic electron emission in a vacuum tube.
(b) Current-voltage characteristics of a vacuum diode.

Fig 4.35
Fermi Dirac function, f(E) and the energy density of electrons, n(E),
(electrons per unit energy and per unit volume) at three different
temperatures. The electron concentration extends more and more to higher
energies as the temperature increases. Electrons with energies in excess of
EF+ can leave the metal (thermionic emission).
0
T3
T2
n(E) = g(E)f(E)
E
T1
Electron concentration
per unit energy
E
EF
+
EF
0 1.0
f(E)
0
Probability
T3
T2
T1
Free Electron

Fig 4.36
Image PE
0
EF
+ 
x x
Net PE
x
EF
+ 
Applied PE
EF
+ eff
(a) (b) (c)
(a) PE of the electron near the surface of a conductor,
(b) Electron PE due to an applied field e.g. between cathode and anode
(c) The overall PE is the sum.

Vo
e-
x = 0 x = xF
EF
(b)
E
Cathode
Grid or Anode
HV V
(c)
(a) Field emission is the tunneling of an electron at an energy EF
through the narrow PE barrier induced by a large applied field. (b)
For simplicity we take the barrier to be rectangular. (c) A sharp point
cathode has the maximumfield at the tip where the field-emission of
electrons occurs.
PE(x)
x
EF
+ eff
xF
Metal Vacuum
EF
0
0
(a)

Fig 4.38
(a) Spindt type cathode and the basic structure of one of the pixels in
the FED.(b) Emission (anode) current vs, gate voltage (c) Fowler-
Nordheim plot that confirms field emission.
30 40 50 60 65
55
45
35
0
100
200
300
400
(b)
Anode current, IA
Gate Voltage VG
0.020 0.024 0.026
-18
-20
-22
0.022
(c)
-16
1/VG
In(I
A
/V
G
2
)
Emission tip
Phosphor
Conducting glass
Gate
Dielectric
VG
(a)
Substrate
+
+
-

Fig 4.39
Wrapped graphite sheet
Capped end with half Buckyball
(a)
(a) A carbon nanotube (CNT) is a whisker-like very thin and long
carbon molecule with rounded ends; almost a perfect shape as an
electron field-emitter. (b) Multiple CNTs as electron emitters. (c) A
single CNT as an emitter.
|SOURCE: Courtesy of Professor W.I. Milne, University of Cam-
bridge; G. Pirio et al, Nanotechnology, 13, 1, 2002.
(c)
(b)

SOURCE: Courtesy of Professor W.I. Milne, University of Cambridge, England. Carbon nanotubes as field emission sources, W. I.
Milne, K. B. K. Teo, G. A. J. Amaratunga, P. Legagneux, L. Gangloff, J.-P. Schnell, V. Semet, V. Thien Binh and O. Groening, Journal
of Materials Chemistry, 14, 933, 2004
Cross-section of a field emission display showing a Spindt tip cathode, (b) Sony portable
DVD player using a field emission display.

Fig 4.40
(a) Harmonic vibrations of an atom about its equilibrium position
assuming its neighbors are fixed. (b) The PE curve V(x) vs. displacement
from equilibrium, x. (c) The enegy is quantized.
M
x
O X
O
+x
x
V(x)
(b)
O
+x
x
En
E0
E1
E2
E3
(a)
(c)

Fig 4.41
ur
ur
(a)
(b)
(c)
0 a 2a ra
xr
= ra No vibrations
(N 1)a
x
L-wave
T-wave
(a) A chain of N atoms through a crystal in the absence of vibrations. (b)
Coupled atomic vibrations generate a traveling longitudinal (L) wave along x.
Atomic displacements (ur) are parallel to x. (c) A transverse (T) wave traveling
along x. Atomic displacements (ur) are perpendicular to the x-axis. b and c are
snapshots at one instant.

Fig 4.42
0

/a
/a
max
0
vg
/a
vgma
x
(a) (b)
(a) Frequency  vs. wavevector K relationship for lattice
(b) Group velocity vg vs. wavevector K.
A
B
K K K

Fig 4.43
Four examples of standing waves in a linear crystal corresponding to
q = 1, 2 and 4. q is maximum when alternating atoms are vibrating
in opposite directions. A portion from a very long is crystal shown.
q = 1
q = 2
q = 4
q = N

Fig 4.44
0 1 2 3 4 5
 (1023
radians/s)  max
Density
of
States
g(

)
Density of states for phonons in copper. The solid curve is deduced from
experiments on neutron scattering . The broken curve is the three-dimensional
Debye approximation, scaled so that the areas under the two curves are the
same. This requires that  max = 4.5  1013 radians s-1, or a Debye
characteristic temperature D = 344 K.

Fig 4.45
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
5
10
15
20
25
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Cu
Si (TD = 625 K)
Cm
J mole-1
Cm/(3R)
T / TD
Cm = 3R
Debye constant-volume molar heat capacity curve. The dependence of
the molar heat capacity Cm on temperature with respect to the Debye
temperature: Cm vs. T/TD. For Si, TD = 625 K so that at room
temperature (300 K), T/TD = 0.48 and Cm is only 0.81(3R).

Fig 4.46
Atoms executing longitudinal vibrations parallel to x.
ur ur+1
ur1
a
x

Fig 4.47
Hot Cold
Unharmonic
interaction
Direction of heat flow
1
2
3
Phonons generated in the hot region travel towards the cold region
and thereby transport heat energy. Phonon-phonon unharmonic
interaction generates a new phonon whose momentum is towards
the hot region.

Fig 4.48
Thermal conductivity of sapphire and MgO as a function of temperature.

Fig 4.49
pf
pi

e
Initial
momentum
pi
pf
Phonon
x
E Final momentum
K
Low angle scaterring of a conduction electron by a phonon

Fig 4.50
Forward wave
B'
A
A'
Reflected waves
C'
B C
k
Backward wave
-k
x
a
An electron wave propagation through a linear lattice. For certain k values
the reflected waves at successive atomic planes reinforce each other to
give rise to a reflected wave travelling in the backward direction. The
electron then cannot propagate through the crystal.

Fig 4.51
c

Energy = Ec
Energy = Es
k = ±  / a
s

Forward and backward waves in the crystal with k = ± /a give rise to
two possible standing waves, c and s. Their probability density
distributions, c and s , have maxima either at the ions or
between the ions.

Fig 4.52
a
O a
a
a
2V1
Ec
Es
First
Brillouin
Zone
Second
Brillouin
Zone
Second
Brillouin
Zone
2V2
k
Energy gap
Energy gap
Band
Band
Band
Allowed
energies
Forbidden
energies
-k
E
Energy
The energy of the electron as a function of its wavevector k inside a one-
dimensional crystal. There are discontinuities in the energy at k = ±n /a
values where the waves suffer Bragg reflections in the crystal. There are
energy gaps at these k values. For example, there can be no energy value for
the electron between Ec and Es. Es  Ec is therefore an energy gap at
k = ± /a. Away from the critical k values, the E-k behavior is like that of a
"free" electron, E increasing with k as E = (k)2/2me. These energies fall
within an energy band inside a solid.

Fig 4.53
Electron

k
k1
k2
Diffracted electron
(11) Planes
(01) Planes
(10) Planes

k3
[01]
[10]
y
x
[11]
45¡
45¡
45¡
a
a
2
a
Diffraction of the electron in a two dimensional cubic crystal. Diffraction occurs
whenever k has a component satisfying k1 = ±n/a, k2 = ±n/a or k3 = ± n/a. In
general terms, when ksin = n/a.

Fig 4.54

a
E
[11]
k3
E
k1
[10]
Band
Band
Energy gap
Energy gap
Band
Band
First
Brillouin Zone
Second Brillouin
Zone
Second
Brillouin Zone
First
Brillouin Zone
a

The E-k behavior for the electron along different directions in the two
dimensional crystal. The energy gap along [10] is at /a whereas it is
at /a along [11].

Fig 4.55
(a) Metal: For the electron in a metal there is no apparent energy gap
because the 2nd BZ (Brillouin Zone) along [10] overlaps the 1st BZ along
[11]. Bands overlap the energy gaps. Thus the electron can always find any
energy by changing its direction.
(b) Semiconductor or insulator: For the electron in a semiconductor there is
an energy gap arising from the overlap of the energy gaps along [10] and
[11] directions. The electron can never have an energy within this energy
gap, Eg.
Energy gap
[11]
[10] Overlapped
energy gaps
Energy gap = Eg
1st BZ
band
2nd BZ
band
(b) Semiconductor and insulator
Energy gap
[11]
[10]
Bands overlap
energy gaps
Energy gap
1st BZ
band
2nd BZ
&
1st BZ
overlapped
band
2nd BZ
band
(a) Metal

Fig 4.56
k1
k2

a
First Brillouin
Zone
Second Brillouin
Zone
[01]
k3
[11]

a 2
a
2
a
[10]
The Brillouin zones in two dimensions for the cubic lattice. The
Brillouin zones identify the boundaries where there are
discontinuities in the energy, where there are energy gaps.

Fig 4.57
Energy contors in k space (space defined by kx, ky). Each contour represents the
same energy value. Any point P on the contor gives the values of kx and ky for
that energy in that direction from O. For the point P, E = 3 eV and OP is k along
[11]. (a) In a metal the lowest energy in the second zone (5 eV) is lower than the
highest energy (6 eV) in the first zone. There is an overlap of energies between
the Brillouin zones. (b) In a semiconductor or an insulator, there is an energy
gap between the highest energy contor (6 eV) in the first zone and the lowest
energy contor (10 eV) in the second zone.
1
2
3
4.5
6
5
7
9
11
O
First BZ
Second BZ
Energy contour
for E = 3 eV in
the first BZ
ky
[01]
k [11]
kx
[10]
(a)
kx
[10]
First BZ
1
2
3
4.5
6
10
12
14
16
k [11]
O
P
ky
[01]
Second BZ
Energy contour
for E = 3 eV in
the first BZ
(b)

Fig 4.58
1st BZ
boundary
2nd BZ
boundary
Be, Cd, Zn
2nd BZ
Boundary
Semiconductor
1st BZ
Boundary
Fermi surface
1st BZ boundary
Li, Na or K Cu, Ag or Au
1st BZ
Schematic sketches of Fermi surfaces in two dimensions to represent
qualitatively various materials. (a) Monovalent Group IA metals (b)
Group IB metals (c) Be (Group IIA), Zn and Cd (Group IIB) (d) A
semiconductor.

Fig 4.59
Intensity
of
emitted
radiation
25 26 27 28 30 31
29
Photon Energy (eV)
Internuclear distance (nm)
0
-5
-10
0 0.5 1 1.5
Energy

Fig 4.60
The photomultiplier tube
e-
Photocathode
Anode
D1 D1
D2
D3
D3
R
Signal
Photon
Dynodes
Vacuum
tube
Examples of photomultiplier tubes
|SOURCE: Courtesy of Hamamatsu

Fig 4.61

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