Lecture L5 092716 ECE 4243/6243 Fall 2016 UConn F Lecture L5 092716 ECE 4243/6243 Fall 2016 UConn F. Jain Optical Modulators (continued L4, Notes Chapter L9, pp. 167-187) and Nanowire/Nanotube Fabrication (Notes L7, pp. 128-139; 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

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

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.

Fabry-Perot Modulator (pp. 178-179)

Fabry-Perot Modulator (pp. 180-181)

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.

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

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

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

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

Nanowire Fabrication (Cao, Chapter 4, pp Nanowire Fabrication (Cao, Chapter 4, pp. 129-130) Growth of Si nanowires using VLS technique

Nanowire Fabrication (Cao, Chapter 4, pp Nanowire Fabrication (Cao, Chapter 4, pp. 132-133) Comparison of axial and lateral Growth of Si and Ge nanowires using VLS technique

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

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

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

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

Carbon Nanotubes (Notes L7 pp.129-139)

Carbon Nanotubes (Notes L7 pp.129-139)

Carbon Nanotubes (Notes L7 pp.129-139)

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. 154-160, 2011 [1] Device W/L = 100mm/30mm 5/19/2018

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

CNT Self-Assembly Scheme on the Gate Region of the MOSFET Croce et. al., Sensors and Actuators B: Chemical, Vol. 160, 1, pp. 154-160, 2011 [1] 5/19/2018

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

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

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

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