Olivier Bourgeois Institut Néel, CNRS Grenoble, Franceiramis.cea.fr/meetings/nanoctm/talks/Bourgeois.pdf · Olivier Bourgeois NANOCTM Cargèse october 2012 Olivier Bourgeois Institut

Olivier Bourgeois NANOCTM Cargèse october 2012

Olivier Bourgeois

Institut Néel, CNRS

Grenoble, France Graduate students :

Christophe Blanc, Hossein Ftouni, Yanqing Liu

Ph D: Jean-Savin Heron

Postdoc: Dimitri Taïnoff, Kunal Lulla

MC Simulations: N. Mingo, A. Rajabpour, S. Volz

Collaborations: A. Barski, E. Hadji, E. Collin, U.

Gennser, D. Kazazis

Electron, photon, phonon Less controlled Manipulating phonons Building blocks for thermal logic

(thermal rectification, thermal diodes, etc…)

Reducing phonon thermal transport

Reduction of thermal conductance

Suspended structures (membrane, nanowire, etc…)

ZT coefficient

“Position Paper on Nanophotonics and Nanophononics”, Clivia M Sotomayor

Torres and Jouni Ahopelto E-Nano Newsletter (Issue 24) Publishing Date: 2011-12-31 Olivier Bourgeois NANOCTM Cargèse october 2012

ZT= S2Tσ/k K=ke+kph

Phonon wave length

Mean free path Roughness

Density of state

Group velocity


Tk

hv

B

SDom

82.2

for silicon

Nanostructured Bulk materials

Ebeam lithography

Focus Ion Beam

J. Tang et al. Nano Letters 10, 4279 (2010) and J.K. Yu et al Nature

Nanotechnology 5, 718 (2010)


Nanoparticles

Embedded in a matrix

superlattice

Grown Nanostructured materials

Better control of the size and roughness


Heat

Transport at

the

nanoscale 1 picoJoule (10-15J)

A. Sikora, H. Ftouni, J. Richard, and O.B.,

Rev. Sci. Instrum. 83, 054902 (2012).

NanoLett 2009, PRB 2010

1 attoJoule (10-18J)

1mm

PRL2005

Rev. Sci. Instrum. 81, 053901 (2010)

Nanowatt

Picowatt

Thermodynamic of Small Systems, Institut Néel

Phononic crystal

Thermoelectrics in GeMn


Blocking ballistic phonons in mono-crystalline silicon

nanowire

Mean free path Lph

LCas=D (Diameter of

the nanowire)

Boundary scattering:

black body radiation

for phonons

Expression for K(T) rB

Vn’

T2

T1 T2 >>

T1


At low temperature, the dominant

phonon wave length is increasing:

Probability of specular reflection p(dom)

depending on dom (phenomenological parameter)

p(dom)=0 (perfectly rough surface)

dom<<h0 Casimir model

p(dom)=1 (perfectly smooth surface)

dom>>h0

rB

→ n Vn’

Vn

h0 is the root mean square of

the asperity


Ziman-Casimir model

Casphp

pL

L

1

1 where p probability of specular

reflection

hh

h

dePp dom2

2316

)()(Probability distribution

of asperity

If p=0 transport is diffusive (Casimir), if p=1 ballistic transport


Straight nanowire Nanowire with serpentine

Length 10µm and section 100nm by 200nm

Olivier Bourgeois NANOCTM Cargèse

october 2012

Low temperature experiments

3w method, heat flux along the nanowire

Low frequency measurement

Sensitive to power less than the picoWatt

V1w

Iac

V3w

D. G. Cahill, Rev. Sci. Instrum. 61, 802 (1990)

L. Lu, W. Yi et D. L. Zhang, Rev. Sci. Instrum. 72, 2996 (2001)

O. B. et al., J. Appl. Phys. 101, 016104 (2007)

J. S. Heron, T. Fournier, N. Mingo and O. B., Nano Lett., 9, 1861 (2009)

J. S. Heron, C. Bera, T. Fournier, N. Mingo and O. B., Phys. Rev. B, 82, 155458

(2010) Olivier Bourgeois NANOCTM Cargèse october 2012

• Iac ~ 1w

• Tac ~ I2 ~ 2w

• R ~ T ~ 2w

• V3w~ IacR ~3w

KNbN<<KSi

w

3

4

23

04

V

RIK

0 1 2 3 4 5 6

0

20

40

60

80

100

120

140

160

K(p

W/K

)

T(K)

K3

K5

K7

K8

Thermal conductance for 4 identical

samples

O. Bourgeois, Th. Fournier, and J. Chaussy, J. Appl. Phys. 101, 016104 (2007) J-S. Heron et al., Journal of Low Temperature Physics , 154, 150 (2009)

h

TkK B

3

22

0

1 10

0.1

1

K/4

KQ

T(K)

K~T3

K~T2

K~T3

Thermal conductance normalized by 4 quanta of conductance

Temperature dependence of

the thermal conductance

Tk

hv

B

SDom

82.2


0 2 4 6

1

10

Lph(µ

m)

T (K)

0 2 4 60.0

0.2

0.4

0.6

0.8

1.0

p

T(K)

Caseffp

pL

L

1

1 111 LL Leffph

Ziman model of phonon transport

3

3/2

33

423

5

2102.3 T

L

S

v

kK

eff

s

BL

Tk

hv

B

SDom

82.2


october 2012 J.-S. Heron, T. Fournier, N. Mingo and O. Bourgeois, Nano Letters 9,

1861 (2009).

1 10

0.1

1

K/4

K0

T(K)

Diffusive transport: classical Casimir

model

Competition between ballistic and diffusive regime: roughness effect

Dominated by the thermal resistance of the wire/reservoir junction (??)

Evidence for the presence of

ballistic phonons

Fitting parameter: •Roughness h4nm

•Speed of sound 9000m/s

•Contribution of the contact

(Chang, C.; Geller, M.

Phys. Rev. B 2005, 71,

125304.)

J.-S. Heron, T. Fournier, N. Mingo and O. Bourgeois, Mesoscopic surface

effects on the phonon transport in silicon nanowire, Nano Letters 9, 1861

(2009).


october 2012

Introducing of a serpentine nanostructure in the suspended nanowire (5µm long)

Length scale 200nm Blocking only the ballistic

phonons

Reduce the thermal conductance


C. W. Chang, D. Okawa, H. Garcia, A. Majumdar and A. Zettl, Phys. Rev. Lett.

99, 045901 (2007).

Reduction of up to 40% of

the thermal conductance

Model this system by

transmission function

analysis

Very good agreement

between the model and

the data

Concerning ballistic

phonons the reduction is

of the order of 80%

J-S. Heron, C. Bera, T. Fournier, N. Mingo, and O. Bourgeois,

Blocking phonons via nanoscale geometrical design, Phys Rev

B 82, 155458 (2010)


• Adaptation of the contact between the nanowire (1D)

and the bath (3D)

L. G. C. Rego et G. Kirczenow, Phy. Rev. Lett. 81, 232 (1998)

Y. Chalopin, J.-N. Gillet, S. Volz, Phy. Rev. B 77, 233309 (2008)

1

0.1

1

10

100

K/K

ca

s

T (K)

Straight

C1

C2

C3

• No effect has been

seen

• No impact of the

thermal resistance

at the interface

• Still below the

universal quantum

of thermal

conductance

Kcas

1

0.1

1

10

100

K/K

ca

s

T (K)

Straight

C1

C2

C3


Reduction of mean free path due to

corrugated surfaces in silicon nanowire

200 nm

10 µm

Multiple scattering

Backscattering in sawtooth nanowire

Reduction of the mean free path


Samples made by ebeam lithography

dom=100nm at 1K in silicon very close to the periodicity of the modulation of roughness

Comparison to smooth nanowire

200 nm

10 µm 320 nm d=200 nm

=200nm

d=55 nm


Thesis Christophe Blanc

T

L

S

v

kTK

s

B L

33

423

5

2102.3)(

Casp

pL

L

1

1


Smooth nanowire have large mean free path

Comparable temperature power law (=2.6)

Mean free path strongly reduced by regular corrugated surfaces

Comparison to smooth nanowire


Presence of

backscattering

Phonon trapped in

the Si teeth


Ali Rajabpour, S. Volz JAP 110, 113529 (2011)

200 nm

10 µm


L

L

T

1

1

• Strong backscattering effect of the corrugation (negative parameter p)

• The corrugation acts like a trap for the phonons • Factor of 10 in the mean free path between smooth

and corrugated wires


Holey silicon nitride (SiN)

Phonon transport in

amorphous SiN

Anderson model in the

Casimir limit ?

New tools for phonon

thermometer



K.J. Lulla, M. Defoort, C. Blanc, O. Bourgeois, and E. Collin, Evidence for the crucial role of normal-state electrons in nanoelectromechanical damping mechanisms at very low temperatures, submitted to Physical Review Letters october 2012.

E. Collin, T. Moutonet, J.-S. Heron, O. Bourgeois, Yu. M. Bunkov, and H. Godfrin,, Physical Review B 84, 054108 (2011).

Collaboration with Eddy Collin

Manipulating phonon: it works !

Strong reduction of mean free path in

corrugated single crystal nanowires

Amorphous materials

Perspectives

Entering in the quantum regime of

thermal transport

2 dimensional electron gas


Thanks to all the members

of the group

Technical pool of Institut

Néel (electronic, Nanofab,

cryogenic facilities)

Collaborations (LITEN, LPN,

Ecole Centrale Paris, INAC,

IC2N (Spain)

Quantherm, QNM

Phononics, COGEETEN

MERGING (FP7, FET)


Documents

Olivier Bourgeois Institut Néel, CNRS Grenoble, Franceiramis.cea.fr/meetings/nanoctm/talks/Bourgeois.pdf · Olivier Bourgeois NANOCTM Cargèse october 2012 Olivier Bourgeois Institut