Post on 17-Jun-2015
description
Organic Field EffectTransistor
Santosh
B10130
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.
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.
There are two common device configurations used in OFETs
1. Top contact
2. Bottom contact
Top contact
When the source and drain electrodes are evaporated on the top of the organic material.
Bottom contact
When the source and drain electrodes are evaporated on the dielectric before depositing the organic semiconductor.
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.
Characteristic of OFETs
Transfer characteristic
Characteristic of OFETs
Output characteristic
Organic Molecule - Pentacene
Pentacene Molecule Organic semiconductor
Composed of five Benzene rings
Polycyclic Aromatic hydrocarbon
Easy to synthesize
High carrier mobility
Pentacene mobility v/s other organics
Organic Field effect Transistor
Advantage DisadvantageCost effective Thermal stability
Large Selection of Material Chemical Stability (Oxidation)
Lighter and flexible
Future of OFET
Skin Cancer treatments
Portable compacts screens
Smart textile
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
Questions???