1. Photonics Activities within Solid State Lab
a) Sensors for Biomedical Applications b) Electroluminescence of FeSi2 in Si c) Polymer Light Emitting Diodes
Department of Electronic Engineering
The Chinese University of Hong Kong

2. Academic units & industrial partners in support of photonic sensor R&D in CUHK
EE – optoelectronics, guided-wave devices, biomedical electronics, signal processing, device fabrication
Biochemistry and Medicine – application area identification, supporting facilities, biomolecule selection, bio-material supply, field trials
Photonic Sensor R&D
ACAE – Centre for Micro and Nano Systems, MEMS, micro-fluidics, device modeling
Physics – laser optics, optical diagnostic facilities, novel materials
E-Care Company Ltd. (wireless healthcare devices)
Automatic Mfg. Ltd. (high volume device manufacturing)
Photonics Instruments (equipment R&D)
Hong Kong Healthcare Services Ltd. (sales and marketing)
Hong Kong Health Digit Co. Ltd. (diagnostic equipment)
Chan & Hau Medical Laboratories (medical services)
Industrial
Partners

3. Micro-Photonic Sensors for Biomedical Applications
CUHK’s photonics technologies and techniques
Surface Plasmon Resonance, Integrated Optics (Prof. Aaron Ho, EE)
Optical Fibre Phosphorescence (Prof. Dennis Lo, Phys)
Biomolecules to be detected
Application Examples:
Health care diagnostics
Environmental monitoring
Food and drink industries
Drug R&D
Agriculture
Antigen/antibody
Oxygen
Toxins
Carcinogens
body fluids/blood/urine
DNA, genomic fingerprints
Virus, cells, bacteria
Pollutants
Food ingredients 1 1

4. Surface Plasmon Resonance Biosensors
Metal q k sp
Surface
Plasmon
Wave
Lowest
Reflectivity

5. Differential Phase SPR Sensor

6. Biomolecule detection response curve
-50 50
100
150
200
250
300
350
400
450
3.7ug/ml
37ug/ml
110ug/ml
BSA Antibody into flow cell
=>specific binding
PBS
Non-BSA Antibody
Into flow cell
=>No binding
differential phase (degrees)
time (sec.)
Reaction curve of BSA (bovine serum albumin) with non-BSA antibody with different concentrations of BSA antibody

7. Sensitivity limit of our SPR system
Phase change caused by varying concentration of glycerin/water mixture (Au surface) 20 40 60 80
100
120
140
160 2 4 6 8 10
Concentration of glycerin (%)
Relative phase change (degree)
Time (min)
glycerin (%)
refractive index
Relative phase change (°)
1.3330
0.25
1.3333
21.75
0.5
1.3336
32.59 1
1.3342
57.53 2
1.3353
89.32 4
1.3400
112.59 8
1.3424
135.69
Sensitivity limit of our system:
Au surface: 1.38 x 10-7 RIU (Refractive Index Unit)
Au/Ag surface: 5.48 x 10-8 RIU

8. Sensitivity Comparison Between Systems
Sensing Principle
BIAcore 3000 (prism-based SPR)
IBIS (vibrating mirror SPR)
Plasmoon (broad-range SPR)
SPREETA (prism-based SPR)
IASys (resonant mirror)
Refractive index range -
Limit of detection (RIU)
*3 × 10-7
2 × 10-6
6 × 10-6
3 × 10-7
>1 × 10-6
Sensitivity limit of our system:
Au surface: 1.38 x 10-7 RIU (Refractive Index Unit)
Au/Ag surface: 5.48 x 10-8 RIU

9. Structural and optical properties of FeSi2 nano-crystal embedded in Si synthesized by MEVVA implantation
PL spectra measured at 80K for two samples with different strain states.
A simple structure of LED device containing FeSi2 nano-crystal
0.7
0.8
0.9
1.0
1.1
1.2
5000
10000
15000
20000
PL Intensity ( m w)
Photo energy (eV)
High strain
low strain
2μm
FZ n-Si
0.5μm
2 nm + -
bias+
FeSi2
p+ Si
SiO2
ITO Al

10. Application of Low Level Birefringence Detection System for Stress Measurement in Semiconductor Materials and Structures
Photoelasticity (PE) method for stress analysis
By measuring the change in the state of polarization of light after passing through the sample, information on the stresses in the sample can be obtained
Low Level Birefringence Detection (LLBD) system
A high sensitive PE technique by using Photoelastic Modulation technique. The sensitivity of current LLBD system is: 0.02º

11. Distribution of residual stress in the 2- inch bare (100) GaAs wafer
Application of Low Level Birefringence Detection System for Stress Measurement in Semiconductor Materials and Structures
tS iO2= 1.3 m
tSi = 380 m
SiO2 x
Distribution of residual stress in the 2- inch bare (100) GaAs wafer
(11 0)
Unit:  107 dyne/cm2 Si y
Plot of distribution of stress induced birefringence in silicon substrate under SiO2 film edge

12. OLED project team members
Project Director: Prof. K. Y. Wong Dept. of Physics
Prof. H. F. Chow Dept. of Chemistry
Prof. S. K. Hark Dept. of Physics
Prof. W. M. Lau Dept. of Physics
Prof. H. C. Ong Dept. of Physics
Dr. K. W. Wong Dept. of Physics
Prof. S. P. Wong Dept. of Electronic Engineering
Prof. J. B. Xu Dept. of Electronic Engineering

13. CUHK’s areas of interest in PLED
Comprehensive in-house material characterization facilities (Physics and EE Depts.) to conduct research on:
a) Interface characterization and engineering
b) Degradation mechanisms and improvement
Development of new materials (Chemistry Dept.)
Device fabrication and technology transfer through collaboration with industry (Varitronix) and other local institutions (HKUST, HKBU)
ITF project in collaboration with Varitronix Ltd. (HK $ 4M)

14. Existing facility for PLED preparation and characterization
XPS, Auger, STM/AFM, SEM, TEM/EELS

15. “Green” PLED cell based
PLEDs fabricated
“Green” PLED cell based
on PFO co-polymer from
DOW Chemicals
“Blue” PLED cell based
on PFO from
Prof. H. F. Chow

16. END
Our team is composed of Prof. Wilson whose expertise is on ion implantation and ion beam analysis, Prof. Wong whose expertise is on ion implantation and thin film technology, for myself my expertise is on scanning probe microscopy and its applications to thin films and devices.
Also there are about 5 research staff and 10 postgraduates constantly.