Si nanopar tic le s: Ne w photonic and e le c tr onic mate r - - PowerPoint PPT Presentation

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Si nanopar tic le s: Ne w photonic and e le c tr onic mate r ial Dr. Munir H. Na yfe h De pa rtme nts o f Physic s, Unive rsity o f I llino is NanoSi L e t the r e be L ight Natur e 2 2 Nano S i F r om bulk to nanopar tic

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SLIDE 1

Si nanopar tic le s: Ne w photonic and e le c tr

  • nic mate r

ial

  • Dr. Munir H. Na yfe h

De pa rtme nts o f Physic s, Unive rsity o f I llino is

slide-2
SLIDE 2

Nano S i

2 2

NanoSi

L e t the r e be L ight

Natur e

slide-3
SLIDE 3

Nano S i

3 3

F r

  • m bulk to nanopar

tic le s

What make s silic on Glow?

I) Bulk Silic on (E mission life time ~ ms) Dull

  • Diffic ult to c o nse rve mo me ntum in tra nsitio n a c ro ss

b a ndg a p. (I ndire c t g a p)

  • Mo me ntum c a n c o me fro m c o upling to c rysta lline

pho no ns. (2nd o rde r pro c e ss)

  • II) Si Nanostr

uc tur e > 3nm (E nhanc e d life time ~ us) F

luor e sc e nt

  • Quantum c o nfine me nt with b ulk-like e missio n
  • Mo me ntum c a n c o me fro m c o upling to c rysta lline

pho no ns

  • Additio na l mo me ntum c a n c o me fro m b o unda ry

sc a tte ring o f e le c tro ns (dk dx la rg e r tha n 1).

III) Si nanopar tic le (1-3nm) (E nhanc e d life time ~ ns) Glow

  • T

ra pping o f e xc ito ns o nto a to mic intrinsic site s (Si-Si fo r e xa mple ) whe re the c o nse rva tio n o f mo me ntum is lifte d. (dire c t g a p? ) Co mb ina tio n o f me c ha nisms

  • S

pac e c o nfine me nt

  • Mo le c ular c o nfine me nt S

e lf-trappe d

  • Othe r

?

3.2eV

1.1eV

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SLIDE 4

Nano S i

4 4

Pr

  • c e ss and pur

ific ation

E le c tr

  • c he mic al e tc h of bulk wafe r

s

1-10 o hm-c m p-type <100> Si Curre nt c o nc e ntra te s a t me nisc us (~30mA/ c m2) Pa rtic le s dispe rse d in a so lve nt via so nic a tio n Pa rtic le s pro duc e d a re H-pa ssiva te d .

Par tic le s pur ifie d b y size via g e l pe rme a tio n

c hro ma to g ra phy; F ra c tio ns e xhib it diffe re nt lumine sc e nc e spe c tra

M R S B u l l e t i n

  • Z. Yamani, H. Thompson, L. AbuHassan, and M. H. Nayfeh , Appl. Phys. Lett. 70, 3404-3406 (1997)
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SLIDE 5

Nano S i

5 5

Swe e t spots in Si c luste r size

A family of magic size s o f hydro g e na te d Si

na no pa rtic le s

No magic size s > 20 a to ms fo r no n-

hydro g e na te d c luste rs

Materialstoday

  • G. Belomoin, J. Therrien, A. Smith, S. Rao, S. Chaieb, M. H. Nayfeh, Appl. Phys. Lett. 80, 841 (2002)
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SLIDE 6

Nano S i

6 6

Size -c olor

  • bandgap

MRS Bulletin

Excitation at bandgap

Eg = 3.5 /sqrt d

1 nm 10A Blue 1.67 nm Green 2.15 nm Yellow 2.9 nm Red

  • Z. Yamani, S. Ashhab, A. Nayfeh and M. H. Nayfeh, J. Appl. Phys. 83, 3929-3931 (1998)
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SLIDE 7

Nano S i

7 7

Silic on Nanopar tic le pr

  • totype

(Quantum Monte Car lo simulation)

  • I. Ide al bulk-like c onfigur

ation

(Band gap of 3.6-3.7 eV)

  • F

ille d fulle re ne c o nfig ura tio n

  • T

e tra he dra l Si c o re (5 a to ms)

  • 24 hydro g e n pa ssiva te d c a g e
  • K

no wn po sitio n o f Si a nd H

  • Hig hly rinc kle d (puc ke rre d b a ll)

(pe nta g o ns a nd he xa g o ns)

1 Td atom and 28 atom fullerene cage

29 Silic o n (ye llo w) 24 Hydro g e n (white )

1 na no me te r

Si

29H 24

  • L. Mitas, J. Therrien, R. Twesten, G. Belomoin, and M. H. Nayfeh, appl. Phys. Lett. 78, 1918 (2001)
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SLIDE 8

Nano S i

8 8

Wide bandgap mate ial:

Re c onstitution into films and solids

T he pa rtic le s a re ha rve ste d in a so lutio n. Pa rtic le s ma y the n b e pro c e sse d into a c e rta in a ssa y using :

§Drying / e va po ra tio n §Spra y §Je t §E

le c tro c he mic a l de po sitio n Pr

  • duc e s wide bandgap solids

(from Acetone) (from water)

slide-9
SLIDE 9

Nano S i

9 9

F r

  • m bulk band str

uc tur e to mole c ular bands (E

xc ite d state s of Si29)

Mole c ular

  • like e xc ite d state

bands --- R ic har d Mar tin

Bulk absorption Particle absorbtion & QMC Time dependent LDH theory Excitation spectra (absorption x emission)

  • S. Rao, J. Sutin, R. Clegg, E. Gratton, M. Nayfeh, S. Habbal, A. Tsolakidis, R. Martin, Phys. Rev. B (2004)
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SLIDE 10

Nano S i

10 10

Single -E le c tr

  • n T

r ansistor s and Me mor y Ce lls

A single -e le c tr

  • n

tr ansis-tor(SE

T ) is a thre e -te rmina l de vic e , with g a te , so urc e , a nd dra in.

Me mor y Nano- c e lls

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SLIDE 11

Nano S i

11 11

Nano me mor y on a supe r c hip

Me tal-oxide -silic on (MOS) Capac itor me mor y Contain unifor m 1 nm silic on nanopar tic le s

1 .0E-1 1 6.0E-1 1 1 .1 E-1 1 .6E-1 2.1 E-1 2.6E-1 3.1 E-1 3.6E-1 4.1 E-1 4.6E-1

  • 5
  • 4
  • 3
  • 2
  • 1

1 2

Gate Voltage (V) Capacitance (F)

B l a c k ( 1 ) , R e d ( 2 ) , B l u e ( 3 ) , O r a n g e ( 5 ) , T u r q ( 8 ) , P u r p l e ( 1 0 )

0 . 0 0 E+0 0 5 . 0 0 E- 11

  • 1. 0 0 E- 10
  • 1. 5 0 E- 10

2 . 0 0 E- 10 2 . 5 0 E- 10 3 . 0 0 E- 10 3 . 5 0 E- 10 4 . 0 0 E- 10 4 . 5 0 E- 10 5 . 0 0 E- 10

  • 2 . 0 0 E+0
  • 1. 9 0 E+0
  • 1. 8 0 E+0
  • 1. 7 0 E+0
  • 1. 6 0 E+0
  • 1. 5 0 E+0
  • 1. 4 0 E+0
  • 1. 3 0 E+0
  • 1. 2 0 E+0
  • 1. 10 E+0 0
  • 1. 0 0 E+0

p-Si substrate Al electrode Al electrode tunnel oxide nanoparticles top oxide +/-

slide-12
SLIDE 12

Nano S i

12 12

Ar

  • matic bi-linke r

s

Be nzoic Ac id, COOH Salic ylic Ac id, OH and COOH T e r e pththalic Ac id, COOH and COOH Anthr anilic Ac ids, COOH and NH2

Butterfly conjugation

Simulations: Structure, Optical properties Chemical activity Vibrations