My decade in nanoelectronics research -the world of individual electrons, atoms, molecules-

Daniel Moraru

-Associate Professor-

Shizuoka University

Graduate School of Science and Technology,

Dept. of Electronics and Materials Science

• My research work

Atomic/molecular-level electronics

Observation of atoms in nanodevices

• My experience in Japan:

PhD and post-doctoral researcher

Research grants: my insights

• My relation with Europe:

Collaboration networks

Double-degree programs for PhD

• Conclusions

Outline

Between Romania and Japan

~10,000 km

Parallel 45

ROMANIA JAPAN

• 1993-1997 M. Sadoveanu High School, Pascani

(Mathematics-Physics section)

• 1997-2001 BSc student @ Al. I Cuza University, Iasi

(Faculty of Physics)

• 2001-2003 MSc student @ Al. I. Cuza University, Iasi

(Plasma Physics, Faculty of Physics)

My research background

• 2004-2007 MEXT PhD scholarship in Shizuoka University

(Nanovision Science/Prof. M. Tabe)

• 2005-2006 Internship at NTT Basic Research Labs

• 2007-2012 Post-doctoral researcher in Research Institute

of Electronics, Shizuoka University

• 2012-2014 Assistant Professor (RIE, Shizuoka University)

• 2015~ Associate Professor (Dept. of Electronics and

Materials Science, Shizuoka University)

ROMANIA

JAPAN

• My research work

Atomic/molecular-level electronics

Observation of atoms in nanodevices

• My experience in Japan:

PhD and post-doctoral researcher

Research grants: my insights

• My relation with Europe:

Collaboration networks

Double-degree programs for PhD

• Conclusions

Outline

ELECTRONICS at smaller and smaller scales:

There’s plenty of room

at the bottom!

Richard Feynman (1918-1988)

(Nobel Prize in Physics: 1967)

IBM movie “Atom”

(STM manipulation of atoms)

Nanoscale

Molecular scale

Atomic scale

1959 2015

Atom/molecular-level

controllability

Motivation for our research

Moore’s

Law

# dopants in device channel 1

Problems for conventional

transistors

Chance for development

of atom devices

Single dopant-atom!

The end of miniaturization of transistors?

Gate voltage (V) D

rain

curr

ent

(A)

Individual Dopant Atom = Quantum Dot (QD)

Single-Dopant-Atom Transistor: concept

Making nanostructures for dopant-atoms

VD VG

VBG 100 nm

SOI

SiO2

SiO2

×900,000

20 nm

14nm SiO2

<5 nm

Si

×3,000,000 5 nm

Si doped with impurities

SiO2

Building Si nanostructures to

host discrete dopant atoms buried SiO2

Al front gate TEM

SEM

Clean Room Nano-transistors

Isolated vs coupled dopant-atoms

50 nm

~50 nm

ND≈1×1018 cm-3

Uniform doping

ND>5×1018 cm-3

“Selective” doping

Statistically: 1 dopant/QD multiple-dopants/QD

M. Tabe et al., Phys. Rev. Lett. (2010) D. Moraru et al., Sci. Rep. (2015)

Measuring current through dopant-atoms

Single-electron tunneling

Variable-T I-V prober (T = 5~300 K)

Gate voltage (V)

Dra

in c

urr

ent

(A)

Transport spectroscopy of dopant-induced QDs

1.2 1.3 1.4 1.510

-14

10-13

10-12

10-11

10-10

I D (

A)

VG (V)

VD = 5 mV T = 15 K

N=1 S D

e- S D

VG

D. Moraru et al., Sci. Rep. (Nature Group) 4,

6219 (2014)

S D N=3~5

1.4 1.6 1.8 2.010

-14

10-13

10-12

10-11

10-10

10-9

I D (

A)

VG (V)

1e- 2e-

3e-

VD = 5 mV

T = 10 K

e- S D

VG

Impact of electric field: tuning in nanoscale

P1

dP-P~10 nm #P=1 dopant/QD

ND ≈ 1×1018 cm-3

Fel VBG

VFG

0 2 4 6 8 10 121.40

1.45

1.50

1.55

1.60

1.65IDS (A)

VBG (V)

VF

G (

V)

5E-15 5E-14 5E-13 5E-12

Vertical electric field effect

Electric-field-induced interfacial molecule

0 2 4 6 8 10 121.40

1.45

1.50

1.55

1.60

1.65IDS (A)

VBG (V)

VF

G (

V)

5E-15 5E-14 5E-13 5E-12

0 5 10 15 200.0

2.5

5.0 -80 -55 -30

Z (

nm

)

Y (nm)

P1 P'1

(i) FZ= 0

φ (meV)

0 5 10 15 200.0

2.5

5.0 -88 -63 -38

Z (

nm

)

Y (nm)

(ii) FZ - Low

P1 P'1

0 5 10 15 200.0

2.5

5.0 -125 -100 -75

Z (

nm

)

Y (nm)

(iii) FZ - High

P1 P'1

A. Samanta, D. Moraru, T. Mizuno, M. Tabe,

Sci. Rep. 5, 17377 (2015)

Looking at dopant atoms/molecules

Surface potential (13~300 K)

Kelvin Probe Force Microscope ele

ctro

nic

pote

ntia

l (V)

P+

P+ P+

VBG = 0 V

ele

ctr

on

ic p

ote

ntia

l (V

)

B

A

C

VBG = -1 V

ele

ctr

on

ic p

ote

ntia

l (V

)

B

A

C

VBG = -2 V

ele

ctr

on

ic p

ote

ntia

l (V

)

B

A

C

VBG = -3 V

ele

ctr

on

ic p

ote

ntia

l (V

)

Observation of e- injection in single dopants

A B C

-3V -2V

-1V 0V

3rd

2nd

B

A

C

1st

Localized electron injection in

individual P dopant-atoms

Low temperature: T = 13 K

M. Anwar, D. Moraru et al., Appl. Phys. Lett. 99, 213101 (2011)

K. Tyszka, D. Moraru et al., J. Appl. Phys. (2015); Appl. Phys. Express (2015)

Single dopant transistors

P

Multi-dopant transfer

Dopant-cluster

systems

P

Dopant detection

P

Double-dopant systems

P

Research on dopant-atom devices

Atoms in nano-pn diodes

P P P

P B

M. Tabe et al., PRL (2010)

E. Hamid et al., PRB (2013)

D. Moraru et al., Sci. Rep. (2015)

A. Samanta et al., Sci. Rep. (2015)

E. Hamid et al., APL (2010)

D. Moraru et al., PRB (2007),

APEX (2009); K. Yokoi et al.,

JJAP (2009), JAP (2010)

A. Udhiarto et al., APEX (2012)

S. Purwiyanti et al. APL (2013)

M. Ligowski et al., APL (2008); M. Tabe etal, Thin Solid Films (2010)

M. Anwar et al., APL (2011); R. Nowak et al., APL (2013)

K. Tyszka et al., J. Appl. Phys. (2015); Appl. Phys. Express (2015)

KFM

P P P P

P

• My research work

Atomic/molecular-level electronics

Observation of atoms in nanodevices

• My experience in Japan:

PhD and post-doctoral researcher

Research grants: my insights

• My relation with Europe:

Collaboration networks

Double-degree programs for PhD

• Conclusions

Outline

Working with great students & researchers

• JSAP Young Scientist Award

Japan Society of Applied Physics

(JSAP) Meeting 2005

• SSDM Young Researcher Award

International Conference on Solid State

Devices and Materials (SSDM) 2006

• Young Scientist Gold Award:

IUMRS-ICEM International

Conference 2012

• JSAP – Silicon Technology

Division Paper Award

(E. Hamid et al., Phys. Rev. B (2013))

Team work Awards at several conferences

• Young Scientist B (若手研究B) 2014-2016 “ソース端ドナー原子のエネルギーフィルタ効果を用いたSiナノトランジスタ”

“Effects of donor atoms near source edge as energy filters

in Si nano-transistors”

Team work research grants (KAKENHI)

CB

EF

ND ≈ 1×1019 cm-3

2-y

ea

rs-w

ork

resu

lts

Proposal

atomic energy filter?! 0.5 0.6 0.7 0.8 0.9 1.0

10-14

10-13

10-12

10-11

10-10

10-9

I D (

A)

VG (V)

1e-

2e- 3e-

@100 K

1×1019

ND (cm-3)

1×1018

x (nm)

~10 nm

sourc

e

Results

high

temp.

• KAKENHI projects Maximum flexibility within the proposed topic.

(Other funding sources are also important.)

• Clarity and simplicity Limited time of Referees + Difficulty with English text

Clear and simple proposals are recommended.

• High impact Published research (awards, good scientific journals,

invited talks)

Proposed research (motivation, background, impact)

• Prepare well ahead of time!/Ask for advice!

My insights for grant applications

• My research work

Atomic/molecular-level electronics

Observation of atoms in nanodevices

• My experience in Japan:

PhD and post-doctoral researcher

Research grants: my insights

• My relation with Europe:

Collaboration networks

Double-degree programs for PhD

• Conclusions

Outline

• Inter-Academia community (Shizuoka Univ.

+ Universities in Eastern & Central Europe) >10 years of conferences, student and staff exchanges,

collaborations and communication

http://iac.icsu.shizuoka.ac.jp/en/

Networks & collaborations

• Double-degree program (DDP) for PhD European students: 3 years in Shizuoka University for

PhD degree a few more years in home university for

European degree = double-degree

http://iac.icsu.shizuoka.ac.jp/en/info/ddp/

NETWORKS

COLLABORATIONS

2005: Wuppertal University, Germany

2006: Iasi, Al. I. Cuza University, Romania

2007: Hamamatsu, Shizuoka University, Japan

2008: Pecs+Budapest, Hungary

2009: Warsaw, Warsaw University of Technology, Poland

2010: Riga, Riga University, Latvia

2011: Sucevita, Al. I. Cuza University, Romania

2012: Budapest, Obuda Univ., Hungary

2013: Sofia, Sofia University, Bulgaria

2014: Riga, Riga University, Latvia

2015: Hamamatsu, Shizuoka University, Japan

Inter-Academia community

network with long-term strong connections …

DDP students: PhD-level collaboration

Maciek Ligowski LT-KFM observation of individual

dopants in silicon nano-transistors

Applied Physics Letters 2008

co-author: Phys. Rev. Lett. 2010

KFM observation of dopant effects in

silicon nanoscale pn junctions

Applied Physics Letters 2013

Thin Solid Films 2014

Roland Nowak

Krzysztof Tyszka KFM characterization of

selectively-doped silicon transistors

J. Appl. Phys. 2015

Appl. Phys. Express 2015

2006-2008 PhD

2010-2013 PhD

2012-2015 PhD

Students from Warsaw Univ. of Technology (DDP):

• My research work

Atomic/molecular-level electronics

Observation of atoms in nanodevices

• My experience in Japan:

PhD and post-doctoral researcher

Research grants: my insights

• My relation with Europe:

Collaboration networks

Double-degree programs for PhD

• Conclusions

Outline

• Research work

Choose research directions of high impact

Clearly define your original approach

• Experience in Japan:

Team work within international groups

Research grants: high impact + timely preparation

• Relation with Europe:

Build and sustain long-term networks

Focus on PhD-level collaborations

Conclusions

Thank you for your attention!