An organic thin-film transistor circuit for large-area temperature-sensing

This thesis explores the application of organic thin-film transistors (OTFTs) for temperature-sensing. The goal of this work is twofold: the understanding of the OTFT's electrical characteristics' temperature dependence, and the creation of OTFT temperature-sensing circuits. We find that OTFTs have temperature-dependent current-voltage (I-V) characteristics that are determined by trap states inside the bandgap. Based on this understanding, a DC OTFT circuit model is developed which accurately fits the measured I-V data in all regions of device operation and at different temperatures. Using this model, we design and fabricate two OTFT temperature-sensing circuits. The first circuit achieves a responsivity of 22mV/°C with 12nW of power dissipation, but has a nonlinear temperature response that is dependent on threshold voltage shifts. The second circuit achieves a responsivity of 5.9mV/°C with 88nW of power dissipation, and has a highly linear temperature response that is tolerant of threshold voltage shifts. Both circuits exceed silicon temperature sensors' typical temperature responsivity of 0.5 - 4mrV/C while dissipating less power. These traits, along with the OTFT's ability to be fabricated on large-area and flexible substrates, allow OTFT temperature sensors to be used in both existing and new application environments.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• He, David Da

Advisor dc:contributor.advisor

• Charles G. Sodini.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/45833

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/45833