This document discusses organic field effect transistors (OFETs). It describes how the first OFET was invented in 1986 using a polythiophene film, and four years later one was made using a small conjugated molecule called sexithiophene. OFETs have three terminals - source, drain, and gate - as well as a semiconductor layer and insulating layer between the semiconductor and gate. There are two common configurations: top contact, where electrodes are deposited on top of the organic material, and bottom contact, where electrodes are deposited on the dielectric before the organic layer. OFETs operate by applying a voltage to the gate to induce an electric field and form an accumulation layer of charges at the semiconductor-dielectric interface. Characteristics include

1. Organic Field Effect
Transistor
Santosh
B10130

2. Introduction
•
Bardeen, Shockley, and Brattain invented the world's first transistor in
1947
•
The first OFET was reported in 1986.
•
It was based on a film of electrochemically grown polythiophene.
•
Four years later, the first OFET employing a small conjugated
molecule (sexithiophene) was fabricated.

3. Device operation
OFETs are composed of three terminals
1. source
2. drain
3. Gate
as well as a semiconductor layer and an insulating layer between the
semiconductor and gate.

4. There are two common device configurations used in
OFETs
1. Top contact
2. Bottom contact

5. Top contact

When the source and drain electrodes are evaporated on the top of the
organic material.

6. Bottom contact

When the source and drain electrodes are evaporated on the dielectric before
depositing the organic semiconductor.

7. Characteristic of OFETs
When we are applied voltage to the gate induces an electric field through the
dielectric and causes the formation of an accumulation layer of charges at the
interface of the semiconductor deposited.
OFET characteristic can be classified as:
a. Transfer Characteristic
b. Output Characteristic

These characteristic depends on whether Vgs is varied while Vds is kept
constant, or Vds is varied while Vgs is kept constant.

8. Characteristic of OFETs

Transfer characteristic

9. Characteristic of OFETs

Output characteristic

10. Organic Molecule - Pentacene
Pentacene Molecule

Organic semiconductor

Composed of five Benzene rings

Polycyclic Aromatic hydrocarbon

Easy to synthesize

High carrier mobility

11. Pentacene mobility v/s other organics

12. Organic Field effect Transistor
Advantage
Disadvantage
Cost effective
Thermal stability
Large Selection of Material
Chemical Stability (Oxidation)
Lighter and flexible

13. Future of OFET
Skin Cancer treatments
Portable compacts screens
Smart textile

14. References
1. http://iopscience.iop.org/1468-6996/10/2/024313/
2. https://smartech.gatech.edu
3. http://www.slideshare.net/organic-transistors?from_search=12

15. Questions???