Contact lamination

Many published results on electronic transport properties of organic materials, where metal contacts are usually made by evaporation of metals, do not describe the quality of the organic/metal interface, and some exotic observed features may perhaps be ascribed to extrinsic effects such as metal diffusion. The relatively simple contact lamination technique may become an alternative, since it provides a means for establishing electrical contacts without the potential disruption of the organic material associated with metal evaporation. The method consists in bringing the organic layer into mechanical contact with an elastomeric element coated with a thin metal film, which can also be patterned. The contacts are robust and reversible... 

Zaumseil J, Someya T, Baldwin K, Bao Z, Loo Y-L and Rogers J A, Nanoscale Organic Transistors Formed by Soft Contact Lamination and Source/Drain Electrodes Supported by High Resolution Rubber Stamps , Appl Phys Lett, 2003 82 793— 795. 

BARBER, M., COPE, R. and SIDWELL, J. (2003) Investigation into the application of food contact laminated materials examination of migration potential and recommendations for safe use (Final report). FSA Project No. A03034. 

Chwang, A. B., and Frisbie, C. D., Field effect transport measnrements on single grains of sexithiophene Role of the contacts, J. Phys. Chem. B, 104, 12202, 2000. Zaumseil, J., Baldwin, K. W., and Rogers, J. A., Contact resistance in organic transistors that use source and drain electrodes formed by soft contact lamination, J. Appl. Phys., 93, 6117, 2003. 

ZaumseU, J., Baldwin, K.W., and Rogers, J.A., Contact resistance in organic transistors that use source and drain electrodes formed by soft contact lamination, J. Appl. Phys., 93, 6117, 2003. 

Combining nTP with soft contact lamination (ScL), which will be discussed in Section 5.5.5, allows functional top-contact devices to be built on plastic substrates... 

Loo and coworkers fabricated organic transistors and complementary inverter circuits on PDMS/PET substrates in which the gold source/drain electrodes and interconnects were patterned by nTP [20]. Figure 5.5.12(a) shows the current-voltage characteristics of a representative pentacene [72] (p-type) TFT fabricated by a combination of nTP and soft contact lamination. The electrical properties of these top-contact devices (charge-carrier mobility 0.1 cmW-s, on/off current ratio 10" )... 

Combining pCP with lamination techniques [85,86], Loo and coworkers fabricated top-contact organic transistor arrays on plastic substrates. This procedure was subsequently called soft-contact lamination (ScL) [87,88]. ScL exploits the conformal properties of PDMS, so individual components of the device can be made separately and then laminated together in the final step. This feature of ScL is particularly useful for assembling OTFTs considering the chemical and mechanical fragility of the organic semiconductor. 

FIGURE 5.5.18 Schematic of soft-contact lamination, (a) Uniform layers of Ti ( 1 nm) and An (15-20 nm) are deposited onto a PDMS-coated plastic substrate, (b) Gold source and drain electrodes and interconnects are defined by microcontact printing, (c) This sheet is laminated against a bottom plastic substrate that contains the gate, dielectric and, semiconductor levels, (d) The completed laminated circuit. Insets magnified view of the laminated circuit and the side profile of a laminated electrode. (From Y.-L. Loo et al., Proc. Natl. Acad. Sci. U.S.A., 99, 10252, 2002.)... 

FIGURE 5.5.22 Schematic of soft-contact lamination for building thin-film transistors. The electrodes are defined by the raised regions of the PDMS stamp. (From J. Zaumseil et al., Appl. Phys. Lett, 82, 793, 2003.)... 

T.-W. Lee et al., Organic light-emitting diodes formed by soft contact lamination, Proc. Natl. Acad. ScL U.S.A., 101, 429, 2004. 

When processes other than contact lamination are used, similar criteria will apply, i.e., elimination of air, temperature control and gelcoat bonding. 

Polymers Impregnation/drop coating/contact lamination Coating in and outside pores Responsive polymers and hydrogels Bakker et al. (2003) , DeLouise et al. (2005) Segal et al. (2007) Wu and Sailor (2009) , Alvarez... 

Ling M-M, Bao Z (2006) Copper hexafluorophthalocyanine field-eflect transistors with enhanced mobility by soft contact lamination. Otg Electron 7 568-575 Brinkmann H, Kelting C, Makarov S, Tsaryova O, Schnurpfeil G, Wohrle D, Schlettwein D (2008) Fluorinated phthalocyanines as molecular semiconductor thin films. Physica Status Solidi A Appl Res 205 409 20... 

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