Transparent conducting thin films optical properties

In this book the chemical, structural, optical, electrical, and interface properties of zinc oxide are summarized with special emphasis on the use of ZnO as transparent conductive electrode in thin film solar cells. This application has a number of requirements, which can be fulfilled by ZnO ... 

Transparent conducting oxides are widely used as electrodes in thin film optoelectronic devices as solar cells and light emitting diodes because of their transparency for visible light and their high electrical conductivity. Highest optical transparency and electrical conductivity are thus key aspects for such applications. Most work on TCO electrodes is, therefore, dedicated to find deposition parameters, which improve these material parameters. In addition, contact properties are essential for the application of TCOs as electrodes. 

In addition to silicon and metals, a third important element being deposited as thin films is diamond (Celii and Butler, 1991 May, 2000). For many years, diamonds were synthesized by a high pressure/high temperature technique that produced bulk diamonds. More recently, the interest in diamonds has expanded to thin films. Diamond has a slew of properties that make it a desired material in thin-film form hardness, thermal conductivity, optical transparency, chemical resistance, electrical insulation, and susceptibility to doping. Thin film diamond is prepared using chemical vapor deposition, and we examine the process in some detail as a prototypical chemical vapor example. Despite its importance and the intensity of research focused on diamond chemical vapor deposition, there remains uncertainty about the exact mechanism. 

The introduction of bridging groups on the thiophene ring modifies the physical and chemical properties of the polymers obtained. The energy of the optical absorption is reduced in FEDOT, Fig. 9.2(k), and poly(ijothia-naphthalene), (PITN) (Wudl et al., 1984), so that in the conductive state thin films are transparent. PEDOT shows high electrochemical stability in the oxidised state and, when combined with poly(styrenesulphonic acid) counter ions, can be processed from aqueous solution. 

Transparent conductive coatings combine high optical transmission with good electrical conductivity. The existence of both properties in the same material is, from the physics point of view, not trivial and is only possible with certain semi-conductors like indium oxide, tin oxide, cadmium oxide, and with thin gold and silver films, e.g. [157]. Particularly antimony or fluorine doped tin oxide (ATO, FTO), tin doped indium oxide (ITO), and aluminium, indium, or boron doped zinc oxide (AZO, IZO, BZO) are of technical importance [157a]. 

Thin networks of SWNT can be prepared as transparent and highly conducting films which, in addition, have very good mechanical properties. They can be prepared in a reproducible way by a rather simple method of fabrication at room temperature that does not require high vacuum conditions or expensive equipment. Moreover, SWNT thin films have no equal in the tunability of their electrical, optical, and mechanical properties. By varying the type of nanotube used or the film preparation procedures, researchers can vary electrical and optical responses by several orders of... 

Thin films are layers of material ranging in thickness from nanometers (10" m) to micrometers (10" m). They are used commonly for coating optical surfaces and also for coatings on semiconductors. Thin films are used to make mirrors, and these can be finely tuned (in terms of their composition and thickness) to obtain optical surfaces with a wide variety of specific reflection properties, such as wavelength specific mirrors and two-way mirrors (the ones that are transparent from one side but reflective from the other). Thin films are also very useful for coating semiconductors to tune their conductive properties for different applications. 

Graphene attracts enormous interest because of its unique properties. Giant intrinsic charge mobility at room temperature makes it a potential material for nanoelectronics. Its optical and mechanical properties are ideal for micro- and nanomechanical systems, thin-film transistors, transparent and conductive composites, electrodes and for photonics. This Chapter will show that Raman Spectroscopy is a very powerful tool for the investigation of graphene, being very sensitive to phonons, electronic states, defects and to the interaction between the fundamental excitations of graphene. 

Alam M.J., Cameron D.C. Optical and electrical properties of transparent conductive ITO thin films deposited by sol-gel process. Thin Solid Films 2000 00 455 59 Alam M.J., Cameron D.C. Investigation of annealing effects on sol-gel deposited indium thin oxide thin films in different atmospheres. Thin Solid Films 2002 420-421 76-82 Anderson H.U., Pennell M.J., Guha J.P. Polymeric synthesis of lead magnesium niobate powders. Adv. Ceram. 1987 21 91-98... 

The ability to induce changes in conductivity and optical properties in thin films of doped polyanilines by exposing them to vapors of m-cresol at room temperature [38] offers a practical alternative to solution processing and possibly reduces significant retention of m-cresol in the film. Coatings made by dispersing Versi-con in film-forming matrices also show marked improvement in transparency and conductivity on exposure to vapors of w-cresol (V. G. Kulkarni, unpublished observations). 

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