Condensed Matter Physics Seminar

2 p.m., Thursday, February 2, 2006
Room 1201, Physics Building

 Organic Semiconductors and Devices: Charge injection and trapping

David Gundlach

(NIST Gaithersburg)

Abstract:  Organic field-effect transistors have received considerable attention for use in low-cost large-area electronics. Although applications will make use of organic thin film transistors (OTFTs) considerable insight about the intrinsic properties of organic semiconductors and extrinsic limitations for device performance can be gained from comparative studies made on OTFTs, single crystal organic field-effect transistors (OFETs), and test structure used for temperature-dependent space-charge-limited current measurements. Generally, FET operation requires: 1) efficient charge injection at the source contact and 2) efficient transport of the charge in the field accumulated channel. In this presentation we will discuss contact formation to p- and n-channel OTFTs and its effect on the device performance. Additionally, we will report on contact formation to single crystals, where forming ohmic contacts is a prerequisite for making and interpreting SCLC measurements. Charge transport and trapping in the bulk of single crystals will be discussed and compared to that at surface of crystals and thin films. The effects on the device operation and stability of the measurement environment and the formation of trap states of chemical origin will also be addressed for single crystals and thin films.
Host:  Hines/Williams
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