Nanophotonics Class 5 Rare earth and quantum dot emitters

HHe LiBeB CNOFNe NaMgAlSiPSClAr KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn FrRaAcRfDbSgBhHsMtUunUuuUub CePrNdPmSmEuGdTbDyHo Er TmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr La 3+ : [Xe] 4f n n=1-14 ….4f n 5s 2 5p 6 Optical doping with lanthanide ions

Energy levels of lanthanide ions 1.5 µm E gap (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)

HHe LiBeB CNOFNe NaMgAlSiPSClAr KCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKr RbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXe CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRn FrRaAcRfDbSgBhHsMtUunUuuUub CePrNdPmSmEuGdTbDyHo Er TmYbLu ThPaUNpPuAmCmBkCfEsFmMdNoLr La 3+ : [Xe] 4f n n=1-14 ….4f n 5s 2 5p 6 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) ErbiumPrasaeodymium

Silica optical fiber transmission spectrum 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)

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 Al 2 O 3, Si 3 N 4, …. polymer silicon

Photonic integrated circuits on silicon 1 mm SiO 2 /Al 2 O 3 /SiO 2 /Si 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.%, °C anneal T.J. Kippenberg et al.

Quantum dot emitters

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 SiO keV Si, 1.7  cm -2 anneal: 1100  C  nanocrystals: 3-5 nm  Silicon quantum dots: particles in a box

X-ray Photo-electron spectroscopy

Luminescence spectrum depends on Si concentration red-shift for larger nanocrystal size 50 keV Si, 1100 o C/10 min, 500 eV D, 3  cm -2  E = meV Bulk Si bandgap 1100 nm

Si + O 2  Si + SiO 2 Shrinking Si quantum dots by oxidation: blue shift  E = meV

5 nm PbS: rock-salt structure Nearly 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