Contact effects in organic field-effect transistors

O Contact Effects in Organic Field-Effect Transistors... 

Section 2.4 Contact Effects in Organic Field-Effect Transistors. Matthew J. Panzer and C. Daniel Frisbie... 

M. J. Panzer and C. D. Frisbie. 2007. Contact effects in organic field-effect transistors. In Organic Field-Effect Transistors, ed. Z. Bao and J. Locklin. Boca Raton, FL CRC Press. 

Tulevski GS, Miao Q, Afzali A, Graham TO, Kagan CR, Nuckolls C (2006) Chemical complementarity in the contacts for nanoscale organic field-effect transistors. J Am Chem Soc 128 1788-1789... 

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. 

Scheinert S, Paasch G (2009) Interdependence of contact properties and field- and density-dependent mobility in organic field-effect transistors. J Appl Phys 105 014509... 

Short intramolecular contacts between chalcogens and other chalcogens or other heteroatoms have been shown to influence molecular geometry, particularly planarity, in many structures of electroactive materials. Hence the position of the chalcogen atom in the material can profoundly affect its properties. For example Crouch et al 2 report the X-ray crystal structure of compound 24 (Figure 10), a candidate for an organic field-effect transistor, showing the effect of intramolecular S- F close contacts (in tandem with H F contacts) on the planarity of the molecule in the solid state. Note also the... 

When a third electrode is added to the structure shown in Fig. 8.12a, below the substrate, it creates an electric field in the insulating substrate, which is perpendicular to the path of the current between the two contacts to the selective layer. Such a structure became known as the Organic Field-Effect Transistor (OFET). It is discussed here and not in Chapter 6 because it belongs to the family of organic chemiresistors. 

Contacts are the elementary building blocks for all electronic devices. These include interfaces between semiconductors of different doping type (homojunc-tions) or of different composition (heterojunctions), and junctions between a metal and a semiconductor, which can be either rectifying (Schottky junction) or ohmic. Because of their primary importance, tire physics of semiconductor jrmc-tions is largely dealt with in numerous textbooks [11, 12]. We shall concentrate here on basic aspects of the metal-semiconductor (MS) and, above all, metal-insulator-semiconductor (MIS) junctions, which are involved in the organic field-effect transistors. 

More importantly, the influence of the metal diffusion on the electronic properties of contacts in Pc field effect transistors is examined. Besides the influence of the metal layers, the influence of Teflon-based functional organic thin films was studied. They can improve the performance of organic field ef-... 

DCNDBQT organic field effect transistors (OFETs) were fabricated on a highly doped n-Si wafer with 30 nm silicon dioxide. Firstly, the silicon surface was rinsed with Dl-water, acetone and iso-propanol in order to remove small particles and organic impurities. Secondly, the substrate was treated with oxygen plasma and silanised for 26 hours at 60 °C by hexamethyldisilazane (HMDS) in order to improve the OFET performance [21]. As source-drain contacts of the bottom contact transistors (BOC) gold was used, which was evaporated through a shadow mask on the silieon dioxide (see Figure 5.2). 

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