Solid State Chemistry for Physics, Information
Technology Devices and Energy
Art Ramirez
Director Device Physics Research
Bell Labs
SSC and Condensed Matter Physics
-Superconductivity : High, low,
symmetry 
-Quantum phase transitions
MgB2
-Magnetism : 1D, 2D, SDW
-Charge Density, Heavy Fermion,
Ferroelectics
Akimitsu et al Nature 2001
Spin entropy (Rln2)
1.0
-Cross cutting themes
0.8
Dy2Ti2O7
-Artificial spatial dimensionality
0.6
s = 1/2
W ~ +0.5K
-Geometrical Frustration : Spin
Liquid, Spin Ice, Negative
thermal expansion in ZrW2O8
0.4
0.2
0.0
Pauling’s Ice Entropy
0
2
4
6
8
10
12
-Mixed valence
Temperature (K)
Ramirez et al, Nature 1999
-Multifunctionality
SSC and CMP – Nation’s Status
Recent Major Discoveries based on SSC
Water-intercalated superconductivity – H2O:N aCoO2
Berry’s phase transport – Nd2Mo2O7
Multi-Ferroics from ISB magnetism– TbMnO3
Single-molecule metal – Ni(tmdt)2
3d Heavy Fermion Metal – LiV2O4
MgB2 2-band Superconductivity
p-wave Superconductivity in Sr2RuO4
Field-induced superconductivity in -BETS2FeCl4
Approach – materials discovery by crystal growth
Tanaka et al, Science 2001
New Materials & Crystal Growth – NRC Proposal
- Crystals are new materials with technological importance
- Much of CMP physics originates with NMCG
- NMCG funding suffered from reduction of industrial labs
- NMCG funding also not in line with major facility funding
Moore's Law
10 um
Modern CMOS
Beginning of
Submicron CMOS
1 um
Deep UV Litho
34 Years of
Scaling History
100 nm
10 nm
90 nm in 2004
 Every generation
– Feature size shrinks by 70%
– Transistor density doubles
– Wafer cost increases by 20%
– Chip cost comes down by 40%
Presumed Limit
to Scaling
 Generations occur regularly
– On average every 2.9 years over
the past 34 years
– Recently every 2 years
1 nm
1970
1980
1990
2000
2010
2020
Courtesy of D. Buss, TI
SSC & CMOS Roadmap

Scaling CMOS to the “End of Roadmap” will require
sophisticated condensed matter physics.
– Gate stack: Atomic and electron orbital understanding of
this complex material system
– Quantum behavior of carriers
• High perpendicular E field
• Stress
– Non-equilibrium Boltzmann transport
– Tunneling: Gate insulator and Drain-to-Substrate
– Simulation

Sophisticated condensed matter physics will also be required
to invent and develop electronics beyond CMOS
– Single Electron Transistor (SET)
– Carbon Nano-tube (CNT)
– Molecular Electronics
SSC needed for new
– Spintronics
IT materials!
– Quantum Computing
Courtesy of D. Buss, TI
Micro- Electro- Mechanical Systems - MEMS
- Mechanical device functionality :
resonators, capacitors, microfluid,
light control
- Silicon lithography : high “Q”,
materials integratable
- Materials compatible
MEMS microphone
Microcompass magnetometer
Lambda Router Mirror
Solid-state Chemistry : Information Device Physics
- Colossal MR
- Ferroelectrics
- Multiferroics
- Organics
300
paramagnetic with polaron hopping
250
ChargeOrdered
Ins.
200
FM metal
-Heterogeneous electronic
phases, charge patterns
150
AF/FM
ins.
100
0 1 4 6 20
5
AF ins.
40
60
% Ca
80
100
-Strongly coupled charge/
spin/lattice degrees of freedom
Solid-state Chemistry : Information Device Physics
- Colossal MR
CaCu3Ti4O12
- Ferroelectrics
- Multiferroics
- Organics
Subramanian et al, 1999
ZrW2O8
14
6
5
SSC Challenge : to combine
local polarizability and strong
interactions, but to
destabilize long rage order
Solid-state Chemistry : Information Device Physics
- Colossal MR
- Ferroelectrics
TbMnO3 – IC
magnetism
- Multiferroics
- Organics
Ni3V2O8 – A Kagome
Staircase
Kimura et al, Nature 2003
-large ME effect related to structures
that induce IC magnetism
14
6
5
Al, Cava, et al
-Large opportunities for materials
that combine AF, helical FM, and
large polarizability
Multiferroics are Rare
Look at common mineral types that combine FE and FM ions
Spinel: AB2O4; Perovskite: ABO3; Pyrochlore: A2B2O7 - hard to find
A4+ and B2,3+.
Solid-state Chemistry : Information Device Physics
- Colossal MR
- Ferroelectrics
- Multiferroics
- Organics
Structure of (EDT-TTF(CH2OH)2)2Mo6O19
From Batail et al.
- Charge Transfer Salts
- Doping Carbon
- Carbon Nanotubes
14
6
5
- Plastic Electronics
Solid State Chemistry and Energy
Best Research-Cell Efficiencies
36
Multijunction Concentrators
Three-junction (2-terminal, monolithic)
Two-junction (2-terminal, monolithic)
Crystalline Si Cells
Single crystal
Multicrystalline
Thin Film Technologies
Cu(In,Ga)Se2
CdTe
Amorphous Si:H (stabilized)
Emerging PV
Dye cells
ARCO
32
Efficiency (%)
28
24
20
(various technologies)
12
Monosolar
0
1975
Kodak
Boeing
RCA
NREL
Kodak
UNSW
Spire
Georgia Tech
Sharp
Georgia Tech
Varian
ARCO
University
RCA
of Maine
RCA
RCA
RCA
RCA
1980
Boeing
RCA
UNSW
NREL
Cu(In,Ga)Se2
14x concentration
UNSW
NREL
NREL
University
So. Florida
Solarex
UNSW
UNSW
UNSW
Stanford
Spire
NREL/
Spectrolab
NREL
NREL
Boeing
Boeing
Photon Energy
NREL
United Solar
University of
Lausanne
United Solar
Solarex
Groningen Siemens
Princeton
University of
Lausanne
UCSB
Kodak
1985
1990
NREL
NREL
Euro-CIS
AMETEK
Masushita
4
Japan
Energy
No. Carolina
State University
Boeing
8
Spectrolab
Westinghouse
Organic cells
16
Spectrolab
1995
Cambridge
University
University Linz
Linz
Berkeley
2000
2005
Art Nozik, DOE Solar Energy Workshop, 2005
Solid-state chemistry and energy
- Saving: solid state lighting O
and inO
- Conversion: fuel cells, solar
fuels, photovoltaics
- Storage: primary and
secondary batteries
- Issues for OLEDs :
conversion efficiency,
operational life
- Small molecules :
improve triplet harvesting,
spectral range
Luminous efficiency of monochrome
OLEDS
Solid-state chemistry and O-Solar Cells
- Materials issues similar to OLEDs :
injection efficiency, transport
efficiency, emission efficiency
- Need new molecules that are :
strong, light-absorbing, band-gap
and exciton level tunable
- C60 : undergoes little structural
distortion upon electron transfer
Solid-state chemistry
and energy control
Conversion: High
thermoelectric figure of merit
in Na0.75CoO2
Cava, Ong, Science 2004
Solid-state chemistry and energy
•Transmission technologies: superconducting
electric cables
•Fuel stream purification technologies :
hydrogen separation membranes …. How to
make hydrogen?
•Fuel transportation : containers, hydrogen
storage materials
•Cuts across chemistry, materials science,
chemical engineering, mechanical engineering
• Hybrid Organic/Inorganic
Self-Assembled Materials and Organic Electronics
Potential Organic Materials
Advantages:
–Printable/manufacturable
–Flexible
–Multi-functional materials/
molecular design (i. e. lowdielectric constant with high EO
coefficient)
–Low-cost
drain
Semiconductor
Source
Drain
Dielectric
Gate
Substrate
0.1 mm
Market
Potential
channel
- Flexible displays
- Smart Tags
- Photovoltaics
- $10B in 10 years
- Lucent has 25 patents
TFT = semiconductor : Single crystal = insulator
- Polycrystalline thin film
transistors
-Semiconductor spun on or
evaporated
Tetracene
- Almost all of plastic electronics
- Naturally occurring free-carrier
density ~ 1017 carriers/cm3 
Tetracene single crystal
3 mm
Yang et al, APL 2002
- Single crystals grown from vapor
transport or melt
- Insulating, free carrier density ~ 10-12
carriers/cm3
-  No fundamental understanding of
doping or trapping in OFETs
- Similar situation in oxides
Surface States in Single Crystals OFETs
Vg
Ag-paint
paralene
0.5 mm
colloidal graphite
Pentacene crystal
Vs-d
The Role of Single Crystals for Organic Electronics
Single Crystal FETs :
–Easily fabricated
–High purity*
–Address issues of relevance for
plastic systems: grain boundaries,
deep traps, doping, reliability
pentacene
Purity :
–Commercial stock extremely
dirty
–E.g. in pentacene (to left)
have few % dihydra, and
quinone impurities
–Need e.g. a pilot manufacturing program
Palstra group, APL 2004
Identify individual H-related traps in pentacene
10-6
Pentacene T = 297 K
10-7
C
10-8
Current (A)
Current (A)
A
0.26 eV
PC @ 420 nm
zero-field equilibrium
bias polarized
10-9
A
-10
10
600 V
10-11
300 V
10-12
Au pads on a Pentacene crystal
Ea = 0.21 eV
600 V
100 V
C
10-13
30 V
300 V
100 V
30 V
Average
Ea = 0.38
-14
10
1
10
Ea = 0.55 eV
100
1000
Voltage
(V) (V)
Bias
Voltage
D. V. Lang et al, PRL, 2004
Crystal FETs from many different molecules
Material
C60
Benzoantracene
Dihydropentacene+Pentacene
TCNQ
Perylene
Br-tetracene
Cl-tetracene
Coronene
Rubrene-(side product)
Antracene
Decapenlypentacene
Tetraflurotetracene
Rubrene
Pentacene
Mobility [cm2/Vs]
---------Ca. 1*10-6
4.3*10-3
1.4*10-3
2.4*10-4
2*10-4
2.3*10-2
4.6*10-4
1.4*10-3
2-7*10-3
2-13
0.2-2.24
Type
n
p
p
p
p
p
p
p
p
p
p
C. Kloc, R. Zeis
PERIODIC TABLE OF THE ORGANICS
S
picture
ymbol
Band gap
B
6 eV
N
5 eV
Name
Benzene
T
A
3.9 eV
Du
CH3
Napthalene
3.1 eV
C
P
2.2 eV
CH3
Tetracene
Anthracene
CH3
CH3
Durene
Py
Pentacene
Cl
Corannulene
Perylene
Ru
ET
S
S
S
S
S
S
S
S
BEDT
Tc
..
.
…
C2n
C60
2.3 eV
Fullerites
Blue = melts at atmospheric pressure
Coronene
Fullerite
NC
CN
NC
CN
TCNQ
Vi
Bell Labs Crystal
Growth Archive
Many samples from
both our archives
and from ongoing
research projects are
available for
measurement by
request
http://www.belllabs.com/research/crystal.html
end