nanophotonics class 5 rare earth and quantum dot emitters
TRANSCRIPT
Nanophotonics
Class 5
Rare earth and quantum dot emitters
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
La3+: [Xe] 4f n n=1-14 ….4f n 5s2 5p6
Optical doping with lanthanide ions
Energy levels of lanthanide ions
1.5 µm
Egap(Si)
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Europium protects the euro
J.F. Suyver, A. Meijerink (UU)
Lanthanide bar codes
Dejneka, PNAS 100, (2003)
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
La3+: [Xe] 4f n n=1-14 ….4f n 5s2 5p6
Optical doping with lanthanide ions
Chemistry (outer-shell behavior) is similar
A. Polman et al., Appl. Phys. Lett. 62, 507 (1993), J.S. Custer et al., J. Appl. Phys. 75, 2809 (1994)
Erbium Prasaeodymium
Silica optical fiber transmission spectrum
1012 Hz
1.3 m
1.55 m
Miya et al., Electron. Lett. 15, 108 (1979)
wavelength vs. time division multiplexing:WDM
Erbium transition at 1.5 m
Er absorption and emission cross sections
absorptionemission
G.N. van den Hoven et al. Appl. Opt. 36, 3338 (1997)
Erbium photoluminescence in various silicate glasses
Wtot=Wrad+CEr-Er[Er][OH]
A. Polman, J. Appl. Phys. 82, 1 (1997)
EXAFS
Local structure around Er in silicate glasses
M.A. Marcus et al., J. of Non-Cryst. Solids 136, 260 (1991)
Planar optical waveguide
Si
high index low index
Waveguide core materials:
• silica glass• Al2O3, Si3N4, ….• polymer• silicon
Photonic integrated circuits on silicon
1 mm
SiO2/Al2O3/SiO2/Si
Al2O3 technology by M.K. Smit et al., TUD
The world’s smallest erbium-doped optical amplifier
1.53 m signal, 1.48 m pump, 10 mW, gain: 2.3 dB
Waveguide spiral size: 1 mm2
minimum bending radius > 50 m
Appl. Phys. Lett. 68, 1886 (1996)
From a FOM prototype to a 40 M$ company …
SymmorphixSunnyvaleCA, USA
1.5 µm microcavity mode imaged through green upconversion
2 MeV Er implantation, 0.35 at.%, + 800 °C anneal
T.J. Kippenberg et al.
Quantum dot emitters
-2
-1
0
1
2
3
4
++++++
- - - - - - -
[100] X
E (
eV
)
Wave Vector
Indirect bandstructure
Silicon is an inefficient light emitter
Si:Er light-emitting diode
G. Franzó et al., Appl. Phys. Lett. 64, 2235 (1994),B. Zheng et al., Appl. Phys. Lett. 64, 2842 (1994)
Er, O doped c-Si
• 5 m SiO2
• 165 keV Si, 1.71017 cm-2
• anneal: 1100 C nanocrystals: 3-5 nm
Silicon quantum dots: particles in a box
106 104 102 100 98
2SiO
600oC
800oC
1000oC
1100oC
Bulk Si
400oC
As-Imp.
Thermal
Inte
nsity
(A
rb. U
nits
)
Binding Energy (eV)
X-ray Photo-electron spectroscopy
Luminescence spectrum depends on Si concentration red-shift for larger nanocrystal size
50 keV Si, 1100 oC/10 min, 500 eV D, 31015 cm-2
600 700 800 9000.0
0.2
0.4
0.6
0.8
1.0 2e16 Si/cm2
4e16 Si/cm2
6e16 Si/cm2
PL
Sig
nal (
a.u.
)
Wavelength (nm)
E = 300-340 meV
Bulk Sibandgap1100 nm
600 700 800 900 1000 1100 12000.0
0.2
0.4
0.6
0.8
1.0
EGAP Bulk Si
0 min 3 min 10 min 15 min 20 min 25 min 30 min
PL
Sig
nal (
a.u.
)
Wavelength (nm)
Si + O2 Si + SiO2
Shrinking Si quantum dots by oxidation: blue shift
E = 300-400 meV
5 nm
PbS: rock-salt structure
Nearly spherical shape, crystal facetsNearly spherical shape, crystal facets
Compound semiconductor quantum dots: PbS
Modified slide from D. Vanmaekelbergh
CdSe: wurtzite
Modified slide from D. Vanmaekelbergh
Compound semiconductor quantum dots: CdSe
Modified slide from D. Vanmaekelbergh
Luminescence from compound semiconductor quantum dots