Flexible Hybrid Electronic Systems

Ananth Dodabalapur

The University of Texas at Austin

Case I Electronic Paper

• Original Proposal (with organic transistor backplanes)– 1996 (Bell Labs)

• First demonstration– 2000/2001(Lucent/E-

Ink)

• Commercial prototypes– Mid 2000

Case II - OFET based RFID

• First proposal (organic FET based RFID– 1995 (Philips)

• Working prototypes– 2005 to 2008

• Commercial production – Beyond 2010

Hybrid Flexible System Design

• Communication– Wireless, wired

• Circuit design• Semiconductor technology

– Lumped silicon– Thin film semiconductors

• Materials• Insulators, conductors

• Other components and devices– Sensors, Actuators, display elements, etc..

• Fabrication– Roll-to-roll (RTR) or other

Thin-Film Semiconductors

• Organic and Polymer– Easiest to print– Proven compatibility with R2R– Mobilities limited to near 1 cm2/V-s*

• Carbon Nanotube films– Can possess higher mobilities (near 80 cm2/V-s) for L = 100

micron devices (Rogers et al., Nature 2008)– Issues of metallic nanotubes– Separation of semiconducting nanotubes yielded 0.5-0.6 cm2/V-

s. (Bao et al, Science 2008)

• Inorganic Semiconductors/Nanowires– High mobilities with Indium oxide (Marks et al., Nature Materials

2006)

Mobilities of organic FETs (Single Crystal, Thin-film small molecule, and polymer) –

Complied from various data

1980 1985 1990 1995 2000 2005 201010-6

10-5

10-4

10-3

10-2

10-1

100

101

102

P-Channel Solution Casted N-Channel Solution Casted P-Channel Vacuum Deposited N-Channel Vacuum Deposited

Mob

ility

[cm

2 /V

s]

Year

TFT Mobility

2002

2003

2004

2005

2006

2007

0.01

0.1

1

10

P-type N-type

Mob

ility

[cm

2 /V

s]

Year

Single Crystal FET Mobilities

In2O3 FETs (Marks et al., Northwestern)

Ion assisted deposition

Mobility > 120 cm2/V-s

Room temperatureprocess

Fabrication methods for Flexible Electronics

• Ink-jet printing

• Gravure

• Flexo

• Screen Printing

• Nano-imprinting

• Laser-based approaches

• Photolithography for R2R

Technical Themes for the Study

• Circuit and system design

• Device physics

• Inorganic and organic semiconductor materials for transistors

• Dielectrics and conductors

• Functional devices and materials (for sensors etc)

• Fabrication processes

Tasks

Timetable

• Nov. 08 Kick Off meeting (All panelists meet with sponsors and WTEC staff at NSF)

• Jan. 09 Baseline workshop at NSF (optional--this surveys US research in the field)

• Feb. 09 Site visits in Asia

• Mar. 09 Site visits in Europe (optional)

• Apr. 09 Final Workshop at NSF

• July 09 Draft Final Report goal