Ischia, 21-23 giugno 2006Riunione Annuale GE 2006 Optical Properties of Porous Silicon Thue-Morse...
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Ischia, 21-23 giugno 2006 Riunione Annuale GE 2006 Optical Properties of Porous Silicon Thue-Morse Multilayers I. Rea , L. Rotiroti, I. Rendina, L. De Stefano Institute for Microelectronic and Microsystem – Dept. of Naples, National Council of Research, Naples, Italy L. Moretti DIMET – University “Mediterranea” of Reggio Calabria, Reggio Calabria, Italy
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Transcript of Ischia, 21-23 giugno 2006Riunione Annuale GE 2006 Optical Properties of Porous Silicon Thue-Morse...
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Optical Properties of Porous
Silicon Thue-Morse Multilayers
I. Rea, L. Rotiroti, I. Rendina, L. De StefanoInstitute for Microelectronic and Microsystem – Dept. of Naples,
National Council of Research, Naples, Italy
L. MorettiDIMET – University “Mediterranea” of Reggio Calabria,
Reggio Calabria, Italy
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Aperiodic vs PeriodicAperiodic vs Periodic
High geometric complexity
Multiple photonic band gaps
Highly localized states
Geometrical periodicity
Single photonic band gap
Bloch-like states
Photonic Bandgap Photonic Bandgap CrystalsCrystals
Photonic Photonic Quasi-CrystalsQuasi-Crystals
1) X. Jiang, Y. Zhang, S. Feng, K. C. Huang, Y. Yi, and J. D. Joannopoulos, “Photonic band gaps and localization in the Thue–Morse structures”, Applied Physics Letters 86, 201110 (2005).
2) F. Qui, R. W. Peng, X. Q. Huang, X. F. Hu, Mu Wang, A. Hu, S. S. Jiang and D. Feng, “Omnidirectional reflection of electromagnetic waves on Thue-Morse dielectric multilayers”, Europhysics Letters 68, 658-663 (2004).
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
The Thue-Morse The Thue-Morse sequencessequences
nth lattice (n+1)st lattice
A AB B BA
S0=[A],
S1=[AB],
S2=[ABBA],
S3=[ABBABAAB],
S4=[ABBABAABBAABABBA],
…
Nlayers=2n
dSn=2dSn-1
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Etching solution: HF/EtOH=30/70
Silicon wafer: p+ type,
<100> orientation,
8-12 m cm resistivity
Calibration curvesCalibration curves
0.4 0.5 0.6 0.7 0.8 0.9 1.0
1.0
1.5
2.0
2.5
Re
fra
cti
ve
In
de
x (
@1
.2m
)
Porosity
Bruggemann Model
0.55 0.60 0.65 0.70 0.75 0.80 0.850
50
100
150
200
C
urr
en
t D
en
sit
y (
mA
/cm
2)
Porosity
A
B
nnAA=1.3, d=1.3, dAA= 0.135 = 0.135 mm
nnBB=1.96, d=1.96, dBB= 0.90 = 0.90 mm
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Normal incidence reflectivityNormal incidence reflectivity
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
S4
S5
Wavelength (nm)
Re
fle
cti
vit
y (
a.u
.)S
3
Experimental Simulation
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
S7
S6
Wavelength (nm)
Re
fle
cti
vit
y (
a.u
.)
Experimental Simulation
Optical Spectrum Analyser (OSA)
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Variable angle reflectivityVariable angle reflectivity
600 800 1000 1200 1400 16000.0
0.5
1.0
=30°
=15°
=0°
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
Wavelength (nm)
Re
fle
ctivity (
a.u
.) TE mode TM mode
SS66
Partial FBGPartial FBGWidth = 70 nmWidth = 70 nm
-30°<-30°<<30°<30°
SS77
Partial FBGPartial FBGWidth = 90 nmWidth = 90 nm
-30°<-30°<<30°<30°
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
600 800 1000 1200 1400 16000.0
0.5
1.0
S7
Re
fle
cti
vit
y (
a.u
.)
Wavelength (nm)
=30°
=15°
=0°
TE mode TM mode
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
1.32 1.34 1.36 1.38 1.40170
180
190
200
210
220Thue-Morse S
6
530±50 nm/RIU
Refractive Index Unit (RIU) Sensitivity
Methanol 1.328Pentane 1.358Isopropanol 1.377Isobutanol 1.396
Re
d S
hif
t (n
m)
Refractive Index
Thue-Morse sensingThue-Morse sensing
Number of layers
High porosity
layer
Low porosity
layer
Peak wavelength
Device thickness
64 81 % 56 % 1030 nm 7.2 m
Ischia, 21-23 giugno 2006Riunione Annuale GE 2006
Thank you for your Thank you for your
attentionattention
