1. Lecture L5 092716 ECE 4243/6243 Fall 2016 UConn F
Lecture L ECE 4243/6243 Fall 2016 UConn F. Jain Optical Modulators (continued L4, Notes Chapter L9, pp ) and Nanowire/Nanotube Fabrication (Notes L7, pp ; Cao, Chapter 4 & 6)
Electron wave function
Hole wave function
Fig. 1(b) Quantum well in the presence of E Eg
Ehh1
Fig. 1(a) E = 0
Ee1

2. Change in index of refraction
Phase Modulator:
Change in index of refraction
A light beam signal (pulse) undergoes a phase change as it transfers an electro-optic medium of length ‘L’
(1)
In linear electro-optic medium
…………………(2)
E= Electric field of the RF driver; E=V/d, V=voltage and d thickness of the layer.
r= linear electro-optic coefficient
n= index

3. MQWs have quadratic electro-refractive effect.
Figure compares linear and quadratic variation Dn as a funciton of field.
Figure shows a Fabry-Perot Cavity which comprises of MQWs whose index can be tuned (Dn) as a funciton of field.

4. Fabry-Perot Modulator (pp. 178-179)

5. Fabry-Perot Modulator (pp. 180-181)

6. Mach-Zehnder Modulator
Here an optical beam is split into two using a Y-junction or a 3dB coupler. The two equal beams having ½ Iin optical power. If one of the beam undergoes a phase change , and subsequently recombine. The output Io is related as
Mach-Zehnder Modulator comprises of two waveguides which are fed by one common source at the input (left side). When the phase shift is 180, the out put is zero. Hence, the applied RF voltage across the waveguide modulates the input light.

7. Heterostructure Acoustic Charge Transprot H ACT Modulator (pp. 187-192)

8. Electro-Optic, Acousto-Optic Modulators (pp. 193-197)

9. Electro-Optic, Acousto-Optic Modulators (pp. 193-197)

10. Nanowire Fabrication (Notes L7 p. 128)
Synthesis:
Nanowires using supersaturated semiconductor-gold alloys in vapor phase
Nanotubes: (a) carbon nanotubes (b) SiC and other non-carbon nanotubes
Quantum dots using chemical synthesis from liquid or vapor phase.
Etching:
Thin quantum well epitaxial layers are grown in appropriate device structure, in–plane etching using nanolithographic techniques. Reactive ion etching, ion milling are two commonly used etching techniques.
Lithography
Imersion lithography using 193 nm Excimer laser
Extreme Ultra Violet (EUV)
13.5 nm
Sn Plasma. 35 Mw Xe
ASML (Wilton, CT) and Nanotech. Albany

11. Nanowire Fabrication (Cao, Chapter 4, pp
Nanowire Fabrication (Cao, Chapter 4, pp ) Growth of Si nanowires using VLS technique

12. Nanowire Fabrication (Cao, Chapter 4, pp
Nanowire Fabrication (Cao, Chapter 4, pp ) Comparison of axial and lateral Growth of Si and Ge nanowires using VLS technique

13. Nanowire Fabrication (Cao, Chapter 4, pp
Nanowire Fabrication (Cao, Chapter 4, pp. 141) Comparison of Growth using VLS and SLS techniques

14. Nanowire Fabrication (Cao, Chapter 4, pp
Nanowire Fabrication (Cao, Chapter 4, pp. 153) Electrophoresis and Electro-spinning

15. Nanowire Fabrication (Cao, Chapter 4, pp
Nanowire Fabrication (Cao, Chapter 4, pp. 165) Electrophoresis and Electro-spinning

16. Nanowire Fabrication (Cao, Chapter 4, pp. 166) Lithography

17. Carbon Nanotubes (Notes L7 pp.129-139)

18. Carbon Nanotubes (Notes L7 pp.129-139)

19. Carbon Nanotubes (Notes L7 pp.129-139)

20. Single-Walled Carbon Nanotube Gated FET
Self-Assembly Methodology
I-V Characteristics
Functionalization Methods
Croce et. Al., Sensors and Actuators B: Chemical, Vol. 160, 1, pp , 2011 [1]
Device W/L = 100mm/30mm
5/19/2018

21. Methodologies for CNT FET Based-Bio/Chemical Sensing
CNT Channel FETs
(Previous Work)
CNT Gate FETs
(Our work)
Croce et al. [1]
Cid et al. [9]
Abe et al. [10]
5/19/2018

22. CNT Self-Assembly Scheme on the Gate Region of the MOSFET
Croce et. al., Sensors and Actuators B: Chemical, Vol. 160, 1, pp , 2011 [1]
5/19/2018

23. Control CNT Gate FET, no DNA/Thrombin
Cross-Sectional Device Schematic
ID-VD Device Characteristics
w/l = 50/25
5/19/2018

24. CNT liquid gate FET: Results
33 uA/mm2)
Functionalization 50 µM Thrombin, wash in .1% SDS
Addition of Thrombin in PBS to Gate, .1, .7 , 1 µM
Gate voltage applied through platinum electrode
5/19/2018

25. SWCNT Thrombin Sensor Device Parameters
CNT Liquid Gate FET: Analysis
SWCNT Thrombin Sensor Device Parameters
Symbol
Quantity
Value
ni (cm-3)
Intrinsic Carrier Concentration
1.5 x 1010
NA (cm-3)
Acceptor Concentration
2 x 1015
ɸpSi (eV)
p-Si Work Function
5.006
ɸCNT (eV)
SWCNT Work Function
4.76 [11]
W (µm)
Device Width
100
L (µm)
Device Length 30
D (Å)
Gate Oxide 40
(a) Energy band diagram with ssDNA aptamer functionalization and the addition of thrombin. (b) Charge density diagram of the ssDNA functionalized SWNT device and (c) with the addition of thrombin.
5/19/2018

26. Aptamer Functionalization Scheme on CNTs Assembled on the Gate
ssDNA Thrombin Aptamer (5’-GGTTGGTGTGGTTGG-3’) modified on 3’ end with NH2
5/19/2018