Semiconductor Semiconductor Nanostructures IINanostructures II
H.vonKänel
H.vonKänel
H.
von
KänelH.
von
Känel
Laboratorium für Festkörperphysik
Laboratorium für Festkörperphysik
ETHZ
ETHZ
App
lications
App
lications
pppp
Lighting
Lighting
Field effect transistors
Field effect transistors
Sensors
Sensors
Sensors
Sensors
–
–Infrared sensors
Infrared sensors
–
–X
X--ray detectorsray detectors
Semiconductor Nanostructures
PeriodictableofelementsPeriodictableofelements
Periodic
table
of
elementsPeriodic
table
of
elements
Semiconductor Nanostructures
Com
p
arison of wurtzite and zincCom
p
arison of wurtzite and zinc--
p
p
blende structures
blende structures
Semiconductor Nanostructures
GroupIIIGroupIII
--
nitrides
nitrides
Group
IIIGroup
III
nitrides
nitrides
Structural data
Structural data
Fundamental band gaps (direct)
Fundamental band gaps (direct)
Semiconductor Nanostructures
Band structures of AlN
,
GaN and InNBand structures of AlN
,
GaN and InN
,
,
All direct
All direct
bandgap
bandgap
bandgap
bandgap
Semiconductors!
Semiconductors!
Ph.D thesis Alexander Vozny
Ph.D thesis Alexander Vozny
ChernivskiNatlUnivUkraine
ChernivskiNatlUnivUkraine
Chernivski
Natl
.
Univ
.,
UkraineChernivski
Natl
.
Univ
.,
Ukraine
2004
2004
Semiconductor Nanostructures
Variation of bandgap with lattice Variation of bandgap with lattice
parameter
parameter
UV
UV--green group III nitridesgreen group III nitrides
Yellow
Yellow--red zinc blende arsenides red zinc blende arsenides --
p
hos
p
hides
p
hos
p
hides
Semiconductor Nanostructures
pp
pp
M.R. Krames et al., J. Display Technol.
M.R. Krames et al., J. Display Technol. 3
3, 160 (2007)
, 160 (2007)
LEDchipdesignsLEDchipdesigns
LED
chip
designsLED
chip
designs
Semiconductor Nanostructures
M.R. Krames, J. Display Technol. M.R. Krames, J. Display Technol. 3
3, 160 (2007)
, 160 (2007)
pp
--n
j
unctions at e
q
uilibrium and forward bias n
j
unctions at e
q
uilibrium and forward bias
p
p
jq
jq
(a)
(b)
(c)
Semiconductor Nanostructures
Osram
‘
sblueLEDchipsOsram
‘
sblueLEDchips
Osrams
blue
LED
chipsOsrams
blue
LED
chips
1
1 ×
×1 mm1 mm2
2
chip size
chip size
B. Hahn et al.
,
Proc. SPIEB. Hahn et al.
,
Proc. SPIE
Semiconductor Nanostructures
350 mA drive current
350 mA drive current
,
,
Vol. 6910 (2008)
Vol. 6910 (2008)
GaNPLintensityvsTDDGaNPLintensityvsTDD
GaN
PL
intensity
vs
.
TDDGaN
PL
intensity
vs
.
TDD
Theory: J.H. You, J. Appl. Phys. Theory: J.H. You, J. Appl. Phys. 101
101, 023516 (2007)
, 023516 (2007)
Semiconductor Nanostructures
EfficiencydroopEfficiencydroop
Efficiency
droopEfficiency
droop
InGaN/GaN QWInGaN/GaN QW--based 1 based 1 ×
×1 mm1 mm2
2
TFFC
TFFC chipschips
Semiconductor Nanostructures
M.R. Krames et al., J
M.R. Krames et al., J. Display Technol. 3, 2007). Display Technol. 3, 2007)
TimeresolvedPLofthickalloysTimeresolvedPLofthickalloys
Time
resolved
PL
of
thick
alloysTime
resolved
PL
of
thick
alloys
SChichibunaturematerials5810(2006)SChichibunaturematerials5810(2006)
Semiconductor Nanostructures
S
.
Chichibu
,
nature
materials
5
,
810
(2006)S
.
Chichibu
,
nature
materials
5
,
810
(2006)
Inv
e
r
s
i
o
n
do
m
a
in
s
f
o
rm
at
i
o
n in
Ga
NInv
e
r
s
i
o
n
do
m
a
in
s
f
o
rm
at
i
o
n in
Ga
N
esodoasoatoGa
esodoasoatoGa
M. Stutzmann et al.
M. Stutzmann et al.
hl(b)
hl(b)
228
228
p
h
ys. stat. so
l
.
(b)
p
h
ys. stat. so
l
.
(b)
228
228
,
,
505 (2001)505 (2001)
Domain formation due to nucleation of Ga
Domain formation due to nucleation of Ga--face and Nface and N--face grainsface grains
Need well
Need well--defined nucleation stepdefined nucleation step
Semiconductor Nanostructures
AlAl
22
OO
33
surfaceterminationandpolaritysurfaceterminationandpolarity
AlAl
22
OO
33
surface
termination
and
polaritysurface
termination
and
polarity
EpiEpi
eadsapphieisOeadsapphieisO
teminatedteminated
Epi
Epi
-
-r
ead
y
sapphi
r
e
is
O
r
ead
y
sapphi
r
e
is
O
-
-
te
r
minatedte
r
minated
O
O--removal during Highremoval during High--T thermal treatmentT thermal treatment
MSttt
MSttt
lh
lh
ttl(b)
ttl(b)
228
228
505(2001)
505(2001)
Semiconductor Nanostructures
M
.
St
u
t
zmann e
t
M
.
St
u
t
zmann e
t
a
l
., p
h
ysa
l
., p
h
ys. s
t
a
t
. so
l
.
(b)
. s
t
a
t
. so
l
.
(b)
228
228
,
505
(2001)
,
505
(2001)
PLinInPLinIn
--
containingalloys
containingalloys
PL
in
InPL
in
In
containing
alloyscontaining
alloys
Spatially varying energy of excited state due to atomic
Spatially varying energy of excited state due to atomic--scale inhomogeneityscale inhomogeneity
ォ復ョﵩ說
ォ復ョﵩ說
ォ
復
ョ
拾ョォ
復
ョ
拾ョ
Semiconductor Nanostructures
Polarization of strained and unstrained Polarization of strained and unstrained
d
d
nitri
d
es nitri
d
es
Semiconductor Nanostructures
O. Ambacher et al., J. Appl. Phys.
O. Ambacher et al., J. Appl. Phys. 85
85, 3222 (1999)
, 3222 (1999)
PolarizationandbandprofilesPolarizationandbandprofiles
Polarization
and
band
profilesPolarization
and
band
profiles
Left image: Polar (0001) oriented heterostructure
Left image: Polar (0001) oriented heterostructure
Right image: non
Right image: non--polar apolar a--face orientationface orientation
Semiconductor Nanostructures
S. Chichibu, nature materials 5, 810 (2006)
S. Chichibu, nature materials 5, 810 (2006)
GaNcolumnsonAlN/Si(111)GaNcolumnsonAlN/Si(111)
GaN
columns
on
AlN/Si(111)GaN
columns
on
AlN/Si(111)
Potential for columnar LEDs with much higher Potential for columnar LEDs with much higher
lihtttiffii
lihtttiffii
li
g
ht
ex
t
rac
ti
on e
ffi
c
i
ency
li
g
ht
ex
t
rac
ti
on e
ffi
c
i
ency
Semiconductor Nanostructures
SensitivityofthehumaneyeSensitivityofthehumaneye
Sensitivity
of
the
human
eyeSensitivity
of
the
human
eye
︺不ョ︺不ョ
︺
﹩
ョ︺
﹩
ョ
Gray: day vision
Gray: day vision
Semiconductor Nanostructures
CIEchromaticitydiagramCIEchromaticitydiagram
CIE
chromaticity
diagramCIE
chromaticity
diagram
CIE = Commission Internationale de l‘EclairageCIE = Commission Internationale de l‘Eclairage
Semiconductor Nanostructures
BlueBlue--pumped YAG phosphorpumped YAG phosphor
R
Pump wavelength 460 nm
Pump wavelength 460 nm
LER decreases with blue leakage!
LER decreases with blue leakage!
Semiconductor Nanostructures
M.R. Krames, J. Display Technol.
M.R. Krames, J. Display Technol. 3
3, 160 (2007)
, 160 (2007)
Chromaticity for blueChromaticity for blue--pumped YAGpumped YAG
y
CCT
CCT ~ 5000 K for 35 % blue leakage (LER = 328 lm/W)~ 5000 K for 35 % blue leakage (LER = 328 lm/W)
TheoreticalmaximumLES
~
283lm/WatCRI
~
80TheoreticalmaximumLES
~
283lm/WatCRI
~
80
Theoretical
maximum
LES
283
lm/W
at
CRI
80Theoretical
maximum
LES
283
lm/W
at
CRI
80
Semiconductor Nanostructures
M.R. Krames, J. Display Technol.
M.R. Krames, J. Display Technol. 3
3, 160 (2007)
, 160 (2007)
MaximumdownMaximumdown
--
conversionefficiency
conversionefficiency
Maximum
downMaximum
down
conversion
efficiency
conversion
efficiency
CE
=
(PCE
=
(P
lk
lk
+P
+P
)/P
)/P
LED
LED
CE(P
CE(P
l
ea
kl
ea
k
+P
+P
conv
conv
)/P
)/P
LED
LED
MRKramesetalJDisplayTechnol3160(2007)
MRKramesetalJDisplayTechnol3160(2007)
M
.
R
.
Krames
et
al
.,
J
.
Display
Technol
.
3
,
160
(2007)M
.
R
.
Krames
et
al
.,
J
.
Display
Technol
.
3
,
160
(2007)
Semiconductor Nanostructures
N
ea
r
ba
n
d
edge
PL
o
f
a
ll
oys
N
ea
r
ba
n
d
edge
PL
o
f
a
ll
oys
eabadedgeoaoyseabadedgeoaoys
S. Chichibu, nature materials 5, 810 (2006)S. Chichibu, nature materials 5, 810 (2006)
Semiconductor Nanostructures
QuantumefficienciesofHBLEDsQuantumefficienciesofHBLEDs
Quantum
efficiencies
of
HBLEDsQuantum
efficiencies
of
HBLEDs
JMPhilliLJMPhilliL
&PhtRi1N42007&PhtRi1N42007
J
.
M
.
Philli
ps,
L
aser
J
.
M
.
Philli
ps,
L
aser
&
Ph
o
t
on
R
ev
i
ew
1
,
N
o.
4
,
2007&
Ph
o
t
on
R
ev
i
ew
1
,
N
o.
4
,
2007
Semiconductor Nanostructures
MaximumLERforRYGB(CCT
=
3000K)MaximumLERforRYGB(CCT
=
3000K)
Maximum
LER
for
RYGB
(CCT
3000
K)Maximum
LER
for
RYGB
(CCT
3000
K)
All linewidths 1 nm
All linewidths 1 nm
CCT = 3000 K
CCT = 3000 K
JM
JM
PhillipsetalLaser&PhotonRev1307(2007)
PhillipsetalLaser&PhotonRev1307(2007)
J
.
MJ
.
M
.
Phillips
et
al
.,
Laser
&
Photon
Rev
.
1
,
307
(2007)
.
Phillips
et
al
.,
Laser
&
Photon
Rev
.
1
,
307
(2007)
Semiconductor Nanostructures
SchemeofGaNSchemeofGaN
HEMTHEMT
Scheme
of
GaNScheme
of
GaN
--
HEMT
HEMT
Semiconductor Nanostructures
SheetchargedensityatAlGaN/GaNinterfacesSheetchargedensityatAlGaN/GaNinterfaces
Sheet
charge
density
at
AlGaN/GaN
interfacesSheet
charge
density
at
AlGaN/GaN
interfaces
O. Ambacher et al., J. Appl. Phys. 85, 3222 (1999)O. Ambacher et al., J. Appl. Phys. 85, 3222 (1999)
Semiconductor Nanostructures
AlAl
GaGa
N/GaNheterostructureN/GaNheterostructure
AlAl
0.090.09
Ga
Ga
0.91
0.91
N/GaN
heterostructureN/GaN
heterostructure
Sheet electron density 2.12
Sheet electron density 2.12 ×
×101012
12
cm
cm-
-2 2 at 4 K
at 4 K
Mobilit
y
60‘000 cmMobilit
y
60‘000 cm
2
2/Vs at 4
K
/Vs at 4
K
y
y
C.R. Elsass et al., Jap. J. Appl. Phys. 39, L1023 (2000)
C.R. Elsass et al., Jap. J. Appl. Phys. 39, L1023 (2000)
Semiconductor Nanostructures
ComparisonofHEMTsComparisonofHEMTs
Comparison
of
HEMTsComparison
of
HEMTs
FSchwierzTUIlmenau2003FSchwierzTUIlmenau2003
Semiconductor Nanostructures
F
.
Schwierz
,
TU
Ilmenau
2003F
.
Schwierz
,
TU
Ilmenau
2003
Com
p
arison of trans
p
ort
p
ro
p
ertiesCom
p
arison of trans
p
ort
p
ro
p
erties
pppp
pppp
Typical room temperature data for important interfaces
Typical room temperature data for important interfaces
Semiconductor Nanostructures
Band structures of Si
,
Ge Band structures of Si
,
Ge
,
,
and
and α
α-
-SnSn
Empirical pseudopotential method, Chelikowski and Cohen 1976
Empirical pseudopotential method, Chelikowski and Cohen 1976
Semiconductor Nanostructures
Semiconductor Nanostructures
Band structures of Band structures of tetrahedrallytetrahedrally
bddidt
bddidt
b
on
d
e
d
sem
i
con
d
uc
t
ors
b
on
d
e
d
sem
i
con
d
uc
t
ors
Note the close similarity of the Ge band structure
Note the close similarity of the Ge band structure
with that of GaAs around
with that of GaAs around Γ
Γ
Semiconductor Nanostructures
G
e
u
n
d
er
b
i
a
xi
a
l str
a
in
G
e
u
n
d
er
b
i
a
xi
a
l str
a
in
GudbaaaGudbaaa
M.V. Fischetti & S.E. Laux, J. Appl. Phys. 80, 2234 (1996)
Semiconductor Nanostructures
Improved hole transport: compressive strainImproved hole transport: compressive strain
E
unstrained
compressively strained
E
k
E
k
k
k
HH
LH
SO
■■
Strain lifts HH
Strain lifts HH--LH degeneracyLH degeneracy
SO
■
■
Heavy holes become lighter
Heavy holes become lighter
■
■
䅮瑩
䅮瑩
-
-
捲潳獩湧睩瑨䱈扡湤汥慤lto湯n
捲潳獩湧睩瑨䱈扡湤汥慤lto湯n
-
-
灡牡扯汩捩瑹
灡牡扯汩捩瑹
■
■
䅮瑩
䅮瑩
捲潳獩湧
睩瑨
䱈
扡湤
汥慤l
瑯
湯n捲潳獩湧
睩瑨
䱈
扡湤
汥慤l
瑯
湯n
灡牡扯汩捩瑹
灡牡扯汩捩瑹
卥Si捯湤畣瑯爠乡湯獴牵捴畲敳
Modulation do
p
ed strained Ge Modulation do
p
ed strained Ge
p
p
quantum wells
quantum wells
Tpicalstctesedfohighmobilitholetanspot
Tpicalstctesedfohighmobilitholetanspot
Semiconductor Nanostructures
T
y
pical
st
ru
ct
ur
e
u
sed
fo
r
high
mobilit
y
hole
t
r
anspo
r
tT
y
pical
st
ru
ct
ur
e
u
sed
fo
r
high
mobilit
y
hole
t
r
anspo
r
t
Record hole mobilit
y
of Ge
q
uantum well Record hole mobilit
y
of Ge
q
uantum well
yq
yq
B. Rössner et al., APL
B. Rössner et al., APL 84
84, 3058 (2004)
, 3058 (2004)
Semiconductor Nanostructures
Most recently (University of Warwick 2012) > 1‘000‘000 cm
Most recently (University of Warwick 2012) > 1‘000‘000 cm
2
2/Vs !
/Vs !
GephotodiodesforIRdetectionGephotodiodesforIRdetection
Ge
photodiodes
for
IR
detectionGe
photodiodes
for
IR
detection
Band gap shift by thermally induced tensile
Semiconductor Nanostructures
strain in Ge on Si
BandgapshiftthroughthermalannealingBandgapshiftthroughthermalannealing
Bandgap
shift
through
thermal
annealingBandgap
shift
through
thermal
annealing
Extractionof the direct band-gapenergy for the as grown (●)
andannealed(
■
⤱
땭瑨楣t慢獯牰瑩潮l慹敲
慮a
慮湥慬敤
(
■
)
1
땭
瑨楣t
慢獯牰瑩潮
污祥l
Semiconductor Nanostructures
G. Isella et al., Semicond. Sci. Technol.
G. Isella et al., Semicond. Sci. Technol. 22
22, S26 (2007)
, S26 (2007)
CMOSCMOS
--
integratedpixeldetector
integratedpixeldetector
CMOS
CMOS
integrated
pixel
detectorintegrated
pixel
detector
CMOS circuit 2.5 µm, 1 metal, 1 poly process of CNM Barcelona
Semiconductor Nanostructures
R. Kaufmann et al., JAP 110, 023107 (2011)
IR image sensor with integrated Ge IR image sensor with integrated Ge
photodetectors
photodetectors
photodetectors
photodetectors
Semiconductor Nanostructures
R. Kaufmann et al., JAP 110, 023107 (2011)
Absorbed photons vs. XAbsorbed photons vs. X--reay tube voltagereay tube voltage
Semiconductor Nanostructures
CurrentCurrent
--
voltagemeasurements
voltagemeasurements
Current
Current
voltage
measurementsvoltage
measurements
Au wire
A
p
-
Si
A
Ge
Ge
Ge
p-Ge
p
Si
Ge
Ge
Ge
n-Si
Semiconductor Nanostructures
InIn--situ measurements in SEMsitu measurements in SEM--chamberchamber
SEM picture of top contact on individual germanium tower
SEM chamber
A
G
p-Si
Id
tungsten tip
Conductive
tungsten
tip
2
µ
m
GeGeGe
p-
G
e
Vd
I-V characteristics measured in-situ
tungsten
tip
2
µ
m
渭卩
SEM ZeissNvision40
10 µm
Semiconductor Nanostructures
Definition of detector
p
ixelsDefinition of detector
p
ixels
p
p
Semiconductor Nanostructures
H. von Känel, Europhysics News
H. von Känel, Europhysics News 43
43, 18 (2012)
, 18 (2012)
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