Organic TFTs

Unfortunately, TFT circuit performance has been limited by relatively poor device characteristics compared with bulk Si. Existing amorphous Si and organic TFT devices are constrained by materials and/or substrate process limitations and result in IF ls with low mobility (less than lcm2/V-s). Thus,... 

The display and PV industries are the first examples of commercially successful macroelectronics. Research is being aggressively pursued to extend these initial successes into a wide range of new areas that require lower cost, higher performance, and compatibility with a variety of substrates. Existing solutions based on amorphous silicon, LTPS and organic TFTs have not been successful because of either cost and/or performance limitations. 

Ohe, T. Nomoto, K. Wada, M. Kasahara, J. 2006. Solution-processed naphthacene-derivative organic TFT. Proceedings of OEC-06 Peer Reviewed Papers, pp. 27. 

Fig. 1.8. Charge distribution across the conducting channel of an organic TFT. The width of each step corresponds to one monolayer.

The vast majority of organic TFTs operate as p-channel accumulation devices. The output current I of a polymer TFTs, when the voltage Vbs across the device is much smaller than the gate voltage Vg, is given by Eq. (1) ... 

The Impact of Gate Dielectrics on the Electrical Functionality of Organic TFTs j 133... 

Over the past decade, a wide range of dielectric materials have been successfully employed as gate dielectrics in organic TFTs. In principal, these materials can be classified as shown in Fig. 6.3 into four groups describing materials with the pur-... 

Fig. 6.3. Schematic overview and classification of gate-dielectric materials used in organic TFTs.

Because of the complexity of the relationships between the properties of the gate dielectric and the performance of organic TFTs and ICs it may be useful to explain... 

In 1998 the commercially available polymer PVP (Mw 20,000) was introduced as a dielectric layer for organic TFTs by the Philips group [19]. It is soluble in common organic solvents (e.g. acetone, n-butanol, propylene glycol monomethyl ether ace-... 

Another important quality criterion for dielectric materials in organic TFTs is their hysteresis. Hysteresis is the shift in threshold voltage depending on the direc-... 

Consequently, organic electronics in combinations of several applications such as organic TFTs and OLEDs have huge potential for low-cost production and large-volume products using a variety of substrates, for example glass, metal foil, or plastics. 

Another advantage of OVPD over VTE is the ability to control surface morphology (Table 9.1, no. 10). Use of two different deposition modes in OVPD enables active design of layer morphology and interfaces with very valuable properties for device improvements this is of particular importance for high-performance organic TFTs. 

Fujisaki, Y. Inoue, Y. Sato, H. Kurita, T. Tokito, S. and Fujikake, H. (2003) Organic TFT-driven Liquid Crystal Cell with Anodic-oxidised Gate Insulator and Double Protection Layer. IDW Digest, 291-294. Gelinck, G.H. Geuns, T.C.T. and de Leeuw, D.M. (2000) High-performance all-polymer integrated circuits. Appl. Phys. Lett., 77, 1487-1489. 

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