AVS 52nd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM-FrM

Invited Paper EM-FrM5
Vapor and Solution Deposited Organic Thin Film Semiconductor Transistors

Friday, November 4, 2005, 9:40 am, Room 309

Session: Organic Electronic Devices
Presenter: T.N. Jackson, Penn State University
Correspondent: Click to Email

Organic thin film transistor (OTFT) device performance now rivals or exceeds that of a-Si:H devices, and low OTFT process temperatures allow fabrication on a range of surfaces including cloth, paper, or polymeric substrates.  However, it is still unclear whether OTFTs will find significant commercial application.  To do so, OTFTs must demonstrate characteristics that differentiate them from other device technologies, especially a-Si:H TFTs.  Potential advantages for OTFTs include the possibility of device and system fabrication on substrates not readily accessible to a-Si:H devices and also reduced cost manufacturing.  For practical device and system use, OTFTs must demonstrate the uniformity, reproducibility, reliability, and integration with other devices, needed for realistic applications.  As a candidate application we have considered the integration of vapor-deposited OTFTs with organic light emitting diodes (OLEDs).  Working with Kodak we have fabricated small test displays that allow us to investigate device characteristics and passivation and isolation requirements for integrating these organic devices. Solution-deposited organic semiconductors may offer important advantages for low-cost processing.  However, solution processed semiconductors typically lack the molecular-level order which may be important for good carrier transport and large field-effect transistor mobility.  Working with J. Anthony (University of Kentucky) we have investigated functionalized pentacenes and pentacene derivatives.  These materials use bulky molecular side groups to control molecular packing and allow solubility in a range of common solvents.  Surprisingly, solution-deposited films of some of these materials show good molecular ordering and using these materials we have been able to fabricate OTFTs with mobility > 1.5 cm@super 2@/V-s.