Healthcare and biomarkers

Gas sensing mechanism

2×4 sensor array & Temperature optimization

1750 1800 1900 1950 1990 2009 20201850

Healthcare 1.0(Infectious disease care)

Healthcare 2.0(Disease care)

Healthcare 3.0(Preventive care)

Mor

talit

y pe

r m

illio

n

7,000

6,000

5,000

4,000

3,000

2,000

1,000

0

90807060504030

0

2010

Age

DiseaseAssociated volatile biomarker (Detection limit)

Health PatientAsthma NO2 (20~30 ppb) NO2 (< 100 ppb)

Diabetes CH3COCH3 (> 0.9 ppm) CH3COCH3 (< 1.8 ppm)

Oral inflammation H2S (> 100 ppb) H2S (< 1 ppm)

Electron beam evaporator(off-axis mode)

Source2x4 array sensor

Back heater

Chip carrier

Heater wire

AuPtPd

Catalyst decoration(on-axis mode)

Metal oxide nanocolumns(In2O3, WO3)

PtPtSiO2/Si

In2O3 WO3Sensing material(a) (b)

(c)

Res

ista

nce

(Ω) Gas in

(reducing gas)

Times (s)

O–O–

O–O–O–O–

O–O–

O–

O–

O–

O–

O–

O–

O–

O–O–O–O–O– O–

O–O–

EF

ECqVs

Electron transfer

Adsorbed oxygen (over 150)

Depletion layerGrain

Double Schottky barriers

Nanocolumn

Nanotube

① High sensitivity ② High selectivity Low-power consumption

Small size sensor Nanostructures & Catalyst

Heater

Sensing material

Sensor array & Data patterning

③

CH3COCH3NO2H2SC6H7

••

•

Gas sensor array based on semiconductors

Fabrication procedures

500 ppb100 200 300 400onoff

CH3COCH3

Pd_In2O3Detection limit : 8.28 ppb

500 ppb100 200 300 400onoff

H2S

Au_WO3Detection limit : 2.47 ppb

50 ppb10 20 30 40onoff

NO2

Au_In2O3Detection limit : 20 ppb

NO2 at 150 oC CH3COCH3 at 300 oC H2S at 250 oC

(a) (b) (c)

(d) (e) (f)

NO2 CH3COCH3 H2S

150 300 250

Au_In2O3 Pd_In2O3 Au_WO3NO2 1 ppm CH3COCH3 10 ppmBare In2O3

Au_In2O3

Pt_In2O3

Pd_In2O3

Bare WO3

Au_WO3

Pt_WO3

Pd_WO3

H2S 1 ppm

(a) (b) (c)

HeaterWO3

Au_WO3

Pt_WO3

Pd_WO3

Heater

In2O3

Au_In2O3

Pt_In2O3

Pd_In2O3

300 oC

300 oC

Bare In2O3

Au_In2O3

Pt_In2O3

Pd_In2O3

Bare WO3

Au_WO3

Pt_WO3

Pd_WO3

(a) (b) (c) Detection limits in high humidity (RH 80%)

• Healthcare, which has been waiting for the patient to be sick, will be replaced by personalized, predictive, preventive and participatory (P4) medicine.

• Disease diagnosis based on exhaled breath is inexpensive and noninvasive method to characterize abnormalities linked to medical conditions.

• Semiconducting gas sensors have been much attention within sensor society cue to their high sensitivity, small size and cost effectiveness and easy to integration with other circuits.

• Sensor arrays enhance the selectivity via data patterning and reduce the power-consumption which is an important parameter for battery-loaded wireless sensors.

• Conventional gas sensing mechanisms could be explained by oxygen adsorption / desorption and double Schottky barriers.

• Glancing angle deposition (GLAD) based on e-beam evaporator was used to fabricate 2x4 sensor array.

• Our results show extremely low detection limits to distinguish the biomarkers from exhaled breath.

• Temperature optimization was carried out using micro-heater as a function of biomarkers

Chemiresistive Gas Sensor Array based on Metal Oxide Semiconductor for Exhaled Breath

One magnet installation on the top surface

Two magnets on both side of oval-shaped harvester

Repulsive force

𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺 (𝒌𝒌) 𝒅𝒅𝒅𝒅𝒅𝒅𝑺𝑺𝒅𝒅𝑺𝑺 (𝒄𝒄)

Base-excited mass-spring-damper system

Piezoelectric Energy Harvesting for Green Energy

Goal of this work

15 𝑚𝑚𝑊𝑊

6 𝜇𝜇𝑊𝑊

Receive & Transmit

On

Stand by / sleepOff

Power

TimeLow energy Bluetooth power consumption

(Average power for 100 messages per day : 500 𝜇𝜇𝑊𝑊)

Sensor

Wireless module

Harvester

Power management circuit

Autonomous sensor system Wasted energy of vehicles

Parasitic Losses : 4 ~ 6%

Engine Losses: 68 ~72%

Idle Losses: 3%Drivetrain Losses: 5 ~ 6%

Wasted energy on roadwayWheels of Vehicles : 21%Roadway vibration, deformation etc.

Goal of this work 5 W/m2 piezoelectric energy harvesting module

Oval-shaped hybrid harvester

Polyurethane-based roadway

Displacement amplification module

250 𝑘𝑘𝑘𝑘𝑘𝑘250 𝑘𝑘𝑘𝑘𝑘𝑘

Experimental setup

Results

1.6 1.8 2.0 2.2 2.4-20

0

20

40

60

80

100

Ope

n-ci

rcui

t vol

tage

(V)

Time (s)

#1 module #2 module

0 20 40 60 80 100

0

4

8

12

16

20

Pow

er d

ensi

ty (W

/m2 )

Velocity (km/h)

Matched by 8kΩ Matched by 6kΩ

0 20 40 60 80

0

4

8

12

16

20

Pow

er d

ensi

ty ( W

/m2 )

Velocity (km/h)

Compact car (910 kg) Midsize car (1540 kg) Truck (1710 kg)

0 20 40 60 80 10040

50

60

70

80

90

Ope

n-ci

rcui

t vol

tage

(V)

Velocity (km/h)

Driver's seat Passenger's seat

Open-circuit voltage from midsize car

Power density from vehicles

Δ𝑦𝑦

D = dT + εE

1) Piezoelectric coefficient, 𝑑𝑑2) Applied stress, 𝑇𝑇

𝑇𝑇𝑑𝑑Direct effect

Faraday’s law

1) Strength of magnet, 𝜙𝜙2) Number of windings on the solenoid, 𝑛𝑛3) Speed of magnetic field change, 𝑑𝑑𝜙𝜙

𝑑𝑑𝑑𝑑

𝑉𝑉 = −𝑛𝑛𝑑𝑑𝜙𝜙𝑑𝑑𝑑𝑑𝑵𝑵𝑺𝑺

6cm (Pristine) 6cm + mass 6cm + two magnets0.30

0.35

0.40

0.45

Harvester types

Spri

ng c

onst

ant,

k (k

gf/m

m)

0.000

0.005

0.010

0.015

0.020

Dam

ping ratio, ζ

6cm (Pristine) 6cm + mass 6cm + two magnets0

20

40

60

80

100

120 Resonance frequency Deformation

Harvester types

Res

onan

ce fr

eque

ncy

(Hz)

0

1

2

3

4

Displacem

ent (mm

)

𝟖𝟖𝟖𝟖 𝑯𝑯𝑯𝑯

𝟓𝟓𝟓𝟓 𝑯𝑯𝑯𝑯𝟔𝟔𝟓𝟓 𝑯𝑯𝑯𝑯

314270

151

6cm + two magnets 6cm + mass 7cm (pristine)0

100

200

300

400

Out

put p

ower

(µW

)

Harvester types

65 Hz 55 Hz 62 Hz

𝟖𝟖𝟑𝟑𝟓𝟓 𝝁𝝁𝝁𝝁𝟐𝟐𝟐𝟐𝟐𝟐 𝝁𝝁𝝁𝝁

𝟑𝟑𝟓𝟓𝟑𝟑 𝝁𝝁𝝁𝝁

0.5 1.0 1.5 2.00.0

0.5

1.0

1.5

2.0

Out

put p

ower

(mW

)

Acceleration (g)

SUS + magnet (6cm, 65 Hz) SUS + mass (6cm, 55 Hz) SUS (7cm, 62 Hz) PI (6cm, 60 Hz)

Input conditions

Oval-shaped PEGAdditional magnet

as massSolenoid coil above magnet

Curved PEGMagnet

Solenoid coil

Considerations

Experimental setup

Results Output characteristics of PEG

Output characteristics of EMG

Solenoid coil

Oval-shaped harvester

Vibration exciter

Magnet (𝜙𝜙 = 10𝑚𝑚𝑚𝑚)

PEG & EMG hybrid harvester test

N = 100 300 500 500 (𝜙𝜙 = 18 𝑚𝑚𝑚𝑚)

𝜙𝜙 = 15 𝑚𝑚𝑚𝑚

6 cm(Pristine)

6 cm + mass(5.86 g)

6 cm + magnet(5.83 g)

Types of the oval-shaped harvesters1) 6 cm harvester without mass2) 6 cm harvester with mass of 5..86 g3) 6 cm harvester with two magnets of 5.83 g

(damping ratio)

Specifications of solenoid coils1) Number of windings on solenoid coil, N : 100, 300, 5002) Inner diameter of coil, 𝜙𝜙: 15, 18 𝑚𝑚𝑚𝑚3) Input vibration : 0.5 g, 65 𝐻𝐻𝐻𝐻

Harvester design

Structural optimization Displacement enhancement strategy

Mechanism of piezoelectric energy harvester (PEG) Mechanism of electromagnetic energy harvester (EMG)

1.27

2.08

2.89

100 turns 300 turns 500 turns0

1

2

3

4

Out

put p

ower

(mW

)

Number of windings on solenoid coil, N

65 Hz, 0.5 g

1.27 𝒅𝒅𝝁𝝁

2.08 𝒅𝒅𝝁𝝁

2.89 𝒅𝒅𝝁𝝁

Electrochemically driven Mechanical Energy Harvesting

Efficient mechanical energy harvesters convert wasted motions and vibrations into useful electricity.

Thermodynamic working principle

The harvester possesses unique benefits at low-frequency motions

We design a ‘mechanically rechargeable battery’ as an energy harvester.

Device fabrication Current generationElectrode and silicon deposition on PI:

Shaping and electrochemical lithiation:

Device assembly with PDMS surfaces:

Bending and bending the device generates potential differences:

Generated current peaks have 3 second half-life:

Repeatedly bending for 1500 times generates continuous current output, with minimal damages observed:

The device accommodates different mechanical frequency inputs:

Applying stress to electrodes changes the electrochemistry:

h

x

y -z

Δ𝜇𝜇bottom−top = ΩLiΔ𝜎𝜎hydro

= ΩLiE

1 − 𝜈𝜈2h3𝑅𝑅

ΩLi =𝜕𝜕𝑉𝑉𝜕𝜕𝑁𝑁𝐿𝐿𝐿𝐿 𝑃𝑃,𝑇𝑇,𝑁𝑁𝑖𝑖≠Li

where

The power output may be described as the following:2 2

Li one-sideLi Li 2 2

2 21 2 1 23 (1 ) 3 (1 )

LiN E V Eh hNR R

ν νµν ν

Ω − − ∆ ∆ = = − −

Input frequency of f = 0.07 Hz, 100 cycles

Input frequency of f = 0.20 Hz, 100 cycles

We may design an energy harvester optimized for specific frequency motion:

0 1000 2000 3000 40000

50

100

150

200

Resis

tanc

e [MΩ

]

Time [s]

5 ppm NO2

S = 121%

0 10 20 30 400

5

10

15

20

Drain voltage [V]

Drai

n cu

rrent

[µA]

VGS-Vth= -30 VVGS-Vth= -20 VVGS-Vth= -10 VVGS-Vth= 0 V

120 160 200 240 280 320 360 400

SnS B3g

SnS Ag

Tg = 240oCTg = 210oCTg = 180oC

Raman shift [cm-1]

Inte

nsity

[arb

. uni

t]

Tg = 150oCTg = 120oCTg = 90oC

SnS2

SnS Ag

<Gas sensor>

< Layer structure> <Raman spectra>

< Thin film transistor>

2-D Materials : The Next-generation Channel Layers

Why 2-D?

MoS2

A injection purge B injection purgeadsorption removal of excess A reaction removal of excess B

and byproducts

<Future electronic devices> <2D layered chalcogenides>

Challenges Large area display Flexible and soft electronics High electronic mobility Low power consumption

Advantages of 2-D materials High electronic mobility Flexible Open band gap high on/off ratio

<MoS2> <SnS>

1. thickness controllability2. Good uniformity 3. Excellent stepcoverage

<ALD process>

1

2

3

4

Film

s th

ickn

ess

Cycle number

<Advantages of ALD>

n-SnS2

2 nm

epoxy

SiO2

d(002)=0.63 nm

340 360 380 400 420 440 460

Inte

nsity

[a.u

]

Raman shift [cm-1]

60s 30s 10s 5s

E2g

A1g

< Layer structure> <Raman spectra>

< Wafer growth>

10 20 30 40 50

annealing in H2S

annealing in Ar

Inte

nsity

[arb

. uni

t]

2θ [degree]

as-dep.

(002)

<Crystallinity> < Thin film transistor>

0.1 V1 V10 V

VDS

Mob

ility

[cm

2 /V

s]

16 V12 V8 V4 V0 V

VGS

SiO2

Al2O3

d=0.59 nm

10 nm

< Layer structure>

SnS2 A1g5 min10 min 30 min60 min

<Raman spectra>

Why ALD?

p-SnS

SnO or SnO2 SnSx SnS2

Sulfurization H2S plasma

<Sulfurization method> <Device fabrication>

Etching & Lift-off method

Thin film transistor

Gas sensor

Research on Next-generation Dynamic Random Access Memory Capacitor

Research trend of DRAM capacitor

Influence of reduced Al-doping concentration on electrical properties of TiO2

Removal of interfacial layers at the interface between polysilicon and dielectric material in SIS or MIS capacitors is necessary for sub 20nm scaled DRAM. So, capacitor structure has been changed to a metal-insulator-metal (MIM) structure recently.

The technology road map for memory devices states that tox less than 0.3nm is necessary for the DRAMs with a design rule of 1Xnm. The ever-shrinking dimensions of DRAM cells with the increasing packing density have made the capacitor size increasingly smaller and currently-used ZrO2 dielectric will not be able to maintain necessary capacitance. We choose rutile TiO2and cubic BeO as the promising dielectric layers for DRAM capacitor.

0 100 200 300 400 500 600-100

-50

0

50SnO2 + 2H2 = SnO + H2O

∆Gr [k

cal/m

ol]

Temperature [oC]

RuO2 + 2H2 = Ru + 2H2O

SnO2 + 2H2 = Sn + 2H2O

-0.50 -0.25 0.00 0.25 0.500

20

40

60

80

100

Diel

ectri

c co

nsta

nt

Applied voltage [V]

Pristine Ann. in H2

Ta-SnO2

RuO2

-2 -1 0 1 210-10

10-8

10-6

10-4

10-2

100

close: Pristineopen: Ann. in H2

Curre

nt d

ensit

y [A

/cm

2 ]

Electric field [MV/cm]

Red: Ta-SnO2

Blue: RuO2

• Regardless of heat treatment, crystal structure and electrical properties of TiO2 do not change on the Ta-SnO2• On the other hand, deterioration by heat treatment was observed on RuO2• The work function of RuO2 decrease from 5.2eV to 4.7eV, while work function of Ta-SnO2 does not change

Ta doped SnO2 as a DRAM capacitor electrode

C. J. Cho et al., J. Mater. Chem. C, 2017,5, 9405-9411

• The competitive adsorption method(co-feeding) significantly reduces TMA chemisorption• In the case of double doping layer, leakage current is effectively suppressed as expectation• tox of the films is negligibly increased

Al doping into rutile phase TiO2 Ideal Dielectric : Higher k & Larger band gap O3

Ru RuO2

TiO2

@ 250oCby ALD

• In order to obtain Rutile TiO2 growth at low temperature, RuO2 interface was induced by O3 oxidation

• Rutile TiO2 has small band gap and n-type nature. Al doping enhance leakage current properties by elevating Schottky barrier height.

• Al doped TiO2 show lower leakage current with same equivalent oxide thickness.

Wurtzite BeO Rocksalt BeO

• Band gap : 10.6eV• Dielectric Constant : 7~8

• Band gap : 10.1eV• Dielectric Constant : 274

• The phase transformation to rocksaltBeO requires really high pressure (~100GPa)

Sahariah and Ghosh, J. App. Phys. (2010) Park et al., Phys. Rev. B (1999)

S. K. Kim et al., Adv. Mater., 2008, 20, 1429-1435

W. J. Jeon et al., ACS Appl. Mater. Interfaces, 2014, 6 (10)

35 40 45 50 55 60 65 70

wurtzite (002)

wurtzite (100)

MgO:BeO=68:32

MgO:BeO=81:19

Inte

nsity

[arb

. uni

t]

2theta [degree]

MgO:BeO=100:0

rocksalt (220)

rocksalt (200)

MgO:BeO=62:38

MgO:BeO=54:46

MgO:BeO=48:52

MgO:BeO=41:59

MgO:BeO=33:67

MgO:BeO=24:76

MgO:BeO=17:83

MgO:BeO=0:100

Stabilization of cubic BeO : BexMg1-xO

Mg increase

Cubic Structure

• Rocksalt-structured BexMg1-xO films have an enhanced dielectric constant (~20)

Thermoelectric Power Generating Systemfor Wearable Devices

Industrial and technological mega-trend

Digital Single Function

Multi-Function,Unconnected

Multi-Function,Connected

Always connected,Smart&Wearable

Battery-freeLow power consumption

Wearable Tech Market to Reach $26B by 2025Potential Role of IoT Drive E- Harvesters

Source; 2014 , IDTechEx

Thermoelectric46%

“The energy harvesting market by component reaching $596 million in 2018, up from $163 million in 2014”

Thermal energy

Electrical energy

Module structure Commercial module

Lairdtech co. IntRMT Int.

Wireless Body-Area Network

Wearable energy havesting from human body

Thermoelectric power generation for wearable devices

Bi2Te3-based material

κσTSZT

2

=

S : Seebeck coefficient σ : Electrical conductivity K : Thermal conductivityT : Temperature

Figu

re-o

f-mer

it, Z

T

Materials synthesis strategies Device design & fabrication

Electron creation mechanism Powder-free hot extrusion Wearable thermoelectric device

A. Nanostructuring B. Texturing

Randomly-oriented Textured

Low mobility High mobility

a-axisc-axis

High density device fabrication ( > 50 pairs)

Proto-type wearble device

FEM modeling (Structure optimization)

Pole figure analysis

Fiber texturing

High reproducibility

J-.H. Bark et al. JMCC (2015)NPG Asia Mater. (2010)

c

a

Epitaxial Multifunctional Oxide Thin Film

Non-volatile control of 2DEG conductivity at LAO/STO interface using ferroelectric polarization switching of epitaxial PZT overlayer.

Electrical conductance is governed by depletion/accumulation of 2DEG as well as conducting filament formation in TaOx layer.

Defect control of oxide layer: Re-RAMOxide interface control: 2DEG

Anion control of epitaxial thin film

Epitaxial SnON thin film exhibited highly improved mechanical hardness due to the compact and dense crystal structure of cubic SnONas a high-pressure phase.

Phase control of thin film with buffer layers

VOx thin film deposited on STO buffer showed pure VO2(A) phase and had high TCR & low resistivity values simultaneously.

TCR: -3.40%/KResistivity: ~0.1 Ω∙cm at RT

TCR: -3.19 %/KResistivity: ~5 Ω∙cm at RTVO2(A)

110

VO2(A)220

V3O7-111

V2O5001

VO2(A)110

Si Substrate

Si Substrate

Thin film deposition technique Thin film analysis methods

Crystalline types of solid Multifunctional oxidePerovskite (ABO3)

ABO

• Ferroelectric, Piezoelectric• Multiferroic• Dielectric• (Anti) ferromagnetic• Metallic, Semiconductor,

Insulator• Superconductor• Colossal Magnetoresistance• Giant Piezoelectric, etc.

Couplings

Epitaxial oxide thin film

• Scientific interests : What is the intrinsic property?• Technological interests : How to enhance the properties?

1. Strain engineering 2. Domain engineering3. Defect engineering4. Interface engineering

Single-crystalline Poly-crystalline

INTRINSIC property from unit cell (elements and symmetry)

+ EXTRINSIC property from grain / domain boundaries

Amorphous

Lack of long-range order

Pulsed Laser Deposition Sputtering

XRD

TEM

AFM

Hall measurement

• Crystallographic structure• Nanostructure analysis

• Morphology of thin film• Carrier concentration• Hall mobility

Vacuum chamber

Substrate

GunPlasma

RFAr+O2

-40 -20 0 20 40-40

-20

0

20

40

Pola

rizat

ion

(µC/

cm2 )

Drive Voltage (V)

Epitaxial Piezoelectric Thin Film on Si forPiezoelectric Micromachined Ultrasonic Transducer

Orientation control by template

: Pt (top electrode): PMN-PZT

: Silicon: SiO2

AC~

relec

rwavehwave

hSi

hpiezo

Acoustic waveguide

: SrRuO3 (bottom electrode)

pMUT single cell 4th generation relaxor ferroelectrics

Template schematic

Optimizing piezoelectric propertyEpitaxial thin film deposition

20 50

Si 0

04SR

O 2

20

SRO

110

CeO

200

2YS

Z 00

2

30 6040 70 80

(110) SRO/CeO2/YSZ/Si

2 theta(°)

Si 0

04

LSM

O 0

02

LSM

O 0

01

CeO

200

2YS

Z 00

2

LSM

O 0

03

2 theta(°)

20 5030 6040 70 80

(001) LSMO/CeO2/YSZ/Si

Structural characterization

Heater

Off-axis Sputtering

Particle with High Energy

Particle with Low Energy

Substrate

Multi-gun off-axis sputtering

• Defect dipole• Point defect

• Domain structure• Domain walls

• Thermal strain• Lattice strain• Strain gradient

• Substrate Clamping

Thin film

Substrate

Composition (% of ferroelectric)

Extrinsic effect of thin Film Strain effect Orientation dependence

GADDS analysis

20 30 40 50 60 70100

101

102

103

104

105

106

107

Inte

nsity

(cps

)

2θ

YSZ

(002

)

YSZ

(004

)

Si (004)

CeO

2(0

02)

CeO

2(0

04)

LSM

O (0

01)

LSM

O (0

02)

LSM

O (0

03)

PMN

-PZT

(001

)

PMN

-PZT

(002

)

XRD P – E curve

Template design for epitaxial piezoelectric film

Single CrystalPZN-4.5%PT

(001)Single CrystalPZN-8%PT

(001)

Ceramics, PZT-5H

Ceramics, PMN-PTCeramics, PZT-8

0.8

0.6

0.4

0.2

0.020 40 60 800

Electric Field (kV/cm)

Stra

in (%

) Single CrystalPZN (001)

1st generation· High d33, k33

· Low TC, TRT, EC, Qm

2nd generation· High TC, TRT, EC

· Low Qm

3rd generation· High d33, k33, Qm

· Low TC, TRT, EC

4th generation· High d33, k33, TC, TRT, EC, Qm

Buffer Layers

Si (001)

SiO2

Si (001)

Piezoelectric Layer

Oxide Electrode

pMUT array

Epitaxial 4th generation relaxor ferroelectrics are chosen for its high d33, TC and TRT values.For pMUT, epitaxial piezoelectric filmshould be deposited on Si. Thus, proper buffer layers are required.

Different lattice constant of oxide films makedifferent orientation on CeO2/YSZ template

Piezoelectric property can be enhanced by extrinsic factors, strain and orientation of thin film.

Epitaxially grown piezoelectric layer on template shows hysteresis loop.

4 X 4 array N X N array

Multi-environmental Energy Harvesting Based on New Energy Conversion Mechanisms

Piezoluminescence stress/strain sensor

Mechanical Energy Light Emission Photobiomodulation Therapy

<In-Vivo Piezo-luminescence driven by Ultrasonic>

Dual phase broadband energy harvester: vibration and magnetic field

30 40 50 60 70 80 90 1000

1020304050607080

Frequency (Hz)

Out

put v

olta

ge (V

)

30 40 50 60 70 80 90 10005

1015202530354045 Beam #1

Beam #2 Beam #3 Beam #4 Beam #5

Frequency (Hz)

Out

put v

olta

ge (V

)

500 μT magnetic field

30 40 50 60 70 80 90 10005

101520253035404550

Beam 1 Beam 2 Beam 3 Beam 4 Beam 5

Frequency (Hz)

Out

put v

olta

ge (V

)

30 40 50 60 70 80 90 1000

102030405060708090

Frequency (Hz)

Out

put v

olta

ge (V

)

Broadband

Electric kettleOscilloscope

E harvester

Energy harvester

Rectifying circuits Oscilloscope

Thermo-magneto-electric generator for low-grade thermal energy Operation principle of thermo-magneto-electric generator (TMEG)

Magnetic Piezoelectric

Heating

Cooling

CurieTemperature

(Tc)

Hard magnet

Soft magnet Piezoelectric

Hot side

Cold side

Hot side (70oC)

Hard magnet (Nd)

Soft magnet (Gd)Cold side (-10oC)

Cantilever (PVDF)

Thermo-Magneto-Electric Generator (TMEG)

2 cm

TMEG

Heat sink module

Applications Heat sink for improving the power output of solar photovoltaic cells

Incorporation of photovoltaic harvesting systems in airborne platforms

Army LEMV Boeing Solar EagleSolar cell heat sink

Exploit thermally induced second order phase transition of soft magnet

Power generating from periodic oscillation of piezoelectric materials on spring

50 100 150 200 250 300 350

0

10

20

30

40

50

60

70 H=500 Oe

Mag

netiz

atio

n (e

mu/

g)

Temperature (K)

-20 -10 0 10 20

-120

-90

-60

-30

0

30

60

90

120

50K 100K 200K 250K 300K 350K

Mag

netiz

atio

n (e

mu/

g)

Magnetic field (kOe) 0.00 0.25 0.50 0.75 1.00-2

0

2

4

Volta

ge (V

)

Time (sec)

Hea

ting

Coo

ling

Heating

Cooling

Inside desktop

Hard magnet on CPU

Gadolinium (Gd)

TMEG operation from CPU heat

LED operation

Ferromagnetic State Paramagnetic State

Thermal E Mechanical E Electrical E

Dual phase energy harvester Applications Vibration condition Magnetic field condition

1 g acceleration E harvesting from a power cord E harvesting from a car Engine

<Stretching>

<Releasing>

Principle of piezoluminescence phenomenon Applications

ZnS: Cu2+

Dynamic 2-D stress/strain sensor

<Strain sensors for intelligent tire>

Piezoluminescence effect

Nano-architectronic Materials & Transparent Conducting Oxide

Background

Chemical exfoliation method

Single crystal nanosheet• The rise of the market of flexible electronics require the

development of new type passive element.

Limitations

Nano-architectronic (using 2D materials)

Experimental process

2D dielectric nanosheets

Solid-statesynthesismethod

Deposition by LB method

Dielectric monolayer

Dielectric property

Deposition thin film (10 L stacked)

Isotherm graph

Introduction Transparent Conducting Electrode

Transparent Conducting Oxide = Low resistivity + High transmittance< 10-4 Ω· > 85 %

(in the visible region)

Flexible display Touch panel

Solar cell Smart window

Transparent Conducting

Oxide

Application for transparent conducting electrode

ITO (Indium Tin Oxide)-> Mainly used as TCO materials

Property of TCOs

“Difficult to apply into flexible plastic substrates”⇒ Developments of alternative TCO materials are required.

Journal of Photonics for Energy 021215-1 Vol. 2, 2012

Oxide/Metal/Oxide Multilayer structure

Oxide

OxideMetal

→ low resistance→ high transmittance→ flexibility

Low resistivity

Visible light

High transmittance

Oxide

Oxide

Metal

noxide

noxide

nmetal

Destructive interference

Anti reflection effect(by refractive index difference of materials)

Reflection ↓

Oxide

SnO2 > < ZnO(doping materials)

Oxide

OxideMetal

Experimental process

Zn doped SnO2 single layer (deposited by CCS)

1 2 3 4 5 6 7 8 9 10SnO2 > < ZnO

<Substrate positions>P 3 P 6P 2

Thickness profile Sheet resistance Hall measurement

Zn doped SnO2 Multilayer structure

Oxide/Metal/Oxide(40 nm/12 nm/40 nm) Zn-doped SnO2 Un-doped SnO2

Substrate Glass PET Glass PET

Sheet resistance(Ω/sq) 5.2 5.6 8.6 8.3

Transmittance (%, @ 550nm) 86 86 79.9 80.5

Transmittance

Bending test

Rms : 1.3 nm

PET

Rms : 1.1 nm

Glass

AFM image Deposited on PET substrate

In Ar+O2 atmosphere

All-solid-state Lithium Thin Film Batteries

Lithium ion batteries

Characteristic of thin film batteries

Lithium ion batteries- Rechargeable battery types - Lithium ions move from the negative

electrode to the positive electrode during discharge

- High discharge current- Highest energy density- Multi-year, Long-term use

NMC

ApplicationLi-ion battery Present Future

MobileIT

EV

Robot

Mobile Phone, PDA

HEV, E-bike

Robot vacuum

High capacity- Phone, PC..

High power- Eco vehicle

High stability- human interface

Market for lithium thin film batteries

Li-ion batteries : lightweight and high energy density power sources

High capacity thin film batteries 3D structured thin film batteries

(a)Fabrication process flow for the three types 3D cathode films(b)Schematic diagram of the polystyrene (PS) template as a function of O2 plasma

etching with corresponding top-view SEM images

Using Microwave plasma etcher(NIST)

Discharge capacity correspondence between the effective surface area and discharge capacityVoltage profile

Flexible thin film batteries Flexible thin film batteries for smart lens

Applications

Battery

Soft lens(PDMS)

Pt/Ti LiFePO4 NiCr/Ti LiPON Li

0 10 20 30 40 50 60 700

20

40

60

80

100

0

10

20

30

40

Cycle number

Coul

ombi

c ef

ficie

ncy

(%)

Capa

city(µ

Ah/c

m2 µ

m)

0 3 6 9 12 15

3.0

3.2

3.4

3.6

3.8

4.0

50th70th 2nd

Capacity (µAh/cm2µm)

Volta

ge (V

)

0.1C-rate

1st

Li

LiPON

LiFePO4Pt/Ti

Polyimide substrate

500 nm

15 20 25 30 35 40 4515 20 25 30 35 40 45

Pt

LiFePO4 (#81-1173)

+ 15

(112

)

+ 32

(121

) +

100(

311)

+ 31

(301

)

+ 79

(211

)

+ 82

(111

)

+ 76

(101

)

+ 38

(200

)

Pt/Ti/PI

LiFePO4/Pt/Ti/PI

2 Theta (degree)

Rela

tive

Inte

nsity

(Arb

.uni

t)

20 30 40

Transparent thin film batteries

200 300 400 500 600 700 800 9000

20

40

60

80

100

90.2%

Wavelength [nm]

Tran

smitt

ance

[%]

Thickness : 360nm

0 25 50 75 100

0.0

0.5

1.0

1.5

2.0

0.1C-rate

Capacity[µAh/cm2µm]

Volta

ge[V

]

Charge Discharge

200 300 400 500 600 700 800 9000

20

40

60

80

100

Wavelength [nm]

Tran

smitt

ance

[%]

82.5%LFP thin film (480nm)

0 10 20 30 40 50

3.0

3.2

3.4

3.6

3.8

4.0

Capacity[µAh/cm2µm]

Volta

ge[V

]

0.2C-rate

Charge Discharge

Cathode material

Anode material

Solid electrolyte

Full cell