Transcript Slide 1
Nanophotonics
Class 5 Rare earth and quantum dot emitters
Optical doping with lanthanide ions H Li Be Na K Rb Cs Fr Mg Ca Sr Ba Ra Sc Y La Ac Ti Zr Hf Rf B C N O F V Nb Ta Db Cr Mo W Sg Mn Tc Re Bh Fe Ru Os Hs Co Rh Ir Mt Al Ni Pd Cu Ag Zn Cd Pt Au Hg Uun Uuu Uub Ga In Tl Si Ge Sn Pb P As Sb Bi S Se Te Po Cl I Br At He Ne Ar Kr Xe Rn Ce Th Pr Pa Nd U Pm Np Sm Pu Eu Am Gd Cm Tb Bk Dy Cf Ho Es
Er
Fm Tm Md Yb No Lu Lr
La
3+
: [Xe] 4f
n
n =1 14 ….4f
n
5s
2
5p
6
E gap (Si)
Energy levels of lanthanide ions
1.5 µm
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)
Optical doping with lanthanide ions H Li Be Na K Rb Cs Fr Mg Ca Sr Ba Ra Sc Y La Ac Ti Zr Hf Rf B C N O F V Nb Ta Db Cr Mo W Sg Mn Tc Re Bh Fe Ru Os Hs Co Rh Ir Mt Al Ni Pd Cu Ag Zn Cd Pt Au Hg Uun Uuu Uub Ga In Tl Si Ge Sn Pb P As Sb Bi S Se Te Po Cl I Br At He Ne Ar Kr Xe Rn Ce Th Pr Pa Nd U Pm Np Sm Pu Eu Am Gd Cm Tb Bk Dy Cf Ho Es
Er
Fm Tm Md Yb No Lu Lr
La
3+
: [Xe] 4f
n
n =1 14 ….4f
n
5s
2
5p
6
Chemistry (outer-shell behavior) is similar Erbium Prasaeodymium A. Polman et al., Appl. Phys. Lett.
62
, 507 (1993), J.S. Custer et al., J. Appl. Phys.
75
, 2809 (1994)
Silica optical fiber transmission spectrum
10
12
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
absorption emission
G.N. van den Hoven et al. Appl. Opt.
36
, 3338 (1997)
Erbium photoluminescence in various silicate glasses W tot =W rad +C Er-Er [Er] [OH ] A. Polman, J. Appl. Phys.
82
, 1 (1997)
Local structure around Er in silicate glasses EXAFS M.A. Marcus et al., J. of Non-Cryst. Solids
136
, 260 (1991)
Planar optical waveguide
high index Si Waveguide core materials: • silica glass • Al
2
O
3
, Si
3
N
4 ,
….
• polymer • silicon low index
SiO 2 /Al 2 O 3 /SiO 2 /Si Photonic integrated circuits on silicon 1 mm Al 2 O 3 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 mm 2 minimum bending radius > 50
m
Appl. Phys. Lett. 68, 1886 (1996)
From a FOM prototype to a 40 M$ company …
Symmorphix Sunnyvale CA, 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
3 2 Silicon is an inefficient light emitter 4 1 0 -1 -2 [100] Wave Vector X Indirect bandstructure
Si:Er light-emitting diode Er, O doped c-Si G. Franzó et al., Appl. Phys. Lett.
64
, 2235 (1994), B. Zheng et al., Appl. Phys. Lett.
64
, 2842 (1994)
Silicon quantum dots: particles in a box • 5 m SiO 2 • 165 keV Si, 1.7
10 17 cm -2 • anneal: 1100 C nanocrystals: 3-5 nm
X-ray Photo-electron spectroscopy 1100 o C 1000 o C 106 800 o C 600 o C 400 o C As-Imp.
Thermal SiO 2 Bulk Si 104 102 100 Binding Energy (eV) 98
Luminescence spectrum depends on Si concentration red-shift for larger nanocrystal size 50 keV Si, 1100 o C/10 min, 500 eV D, 3 10 15 cm -2 1.0
0.8
0.6
0.4
0.2
0.0
600 2e16 Si/cm 2 4e16 Si/cm 2 6e16 Si/cm 2 E = 300-340 meV 700 800
Wavelength (nm)
900 Bulk Si bandgap 1100 nm
Shrinking Si quantum dots by oxidation: blue shift Si + O 2 Si + SiO 2
1.0
0.8
0.6
0.4
0.2
0 min 3 min 10 min 15 min 20 min 25 min 30 min E GAP Bulk Si E = 300-400 meV
0.0
600 700 800 900 1000 1100 1200
Wavelength (nm)
Compound semiconductor quantum dots: PbS 5 nm Nearly spherical shape, crystal facets PbS: rock-salt structure Modified slide from D. Vanmaekelbergh
Compound semiconductor quantum dots: CdSe CdSe: wurtzite Modified slide from D. Vanmaekelbergh
Luminescence from compound semiconductor quantum dots Modified slide from D. Vanmaekelbergh