Semiconductor films

Du Pont produces this polymer under the trade names of Kapton, Pyrafin, Vespel, and Pyre-ML. The trade names refer to polyimides used for film, semiconductor coatings, mol ding applications, and wire enamel, respectively. They have exceUent thermal, electrical, and physical properties. 

For applied work, an optical characterization technique should be as simple, rapid, and informative as possible. Other valuable aspects are the ability to perform measurements in a contactless manner at (or even above) room temperature. Modulation Spectroscopy is one of the most usehil techniques for studying the optical proponents of the bulk (semiconductors or metals) and surface (semiconductors) of technologically important materials. It is relatively simple, inexpensive, compact, and easy to use. Although photoluminescence is the most widely used technique for characterizing bulk and thin-film semiconductors. Modulation Spectroscopy is gainii in popularity as new applications are found and the database is increased. There are about 100 laboratories (university, industry, and government) around the world that use Modulation Spectroscopy for semiconductor characterization. 

For characterization purposes of bulk or thin-film semiconductors the features at Eq and E] are the most useflil. In a number of technologically important semiconductors (e.g., Hgi j d Te, and In Gai j ) the value of. ) is so small that it is not in a convenient spectral range for Modulation Spectroscopy, due to the limitations of light sources and detectors. In such cases the peak at E can be used. The features at Eq and are not useflil since they occur too far into the near-ultraviolet and are too broad. 

Phonon modes of metals and films, semiconductors, and insulators... 

Kashyout AB, Arico AS, Monforte G, Crea E, Antonucci V, Giordano N (1995) Electrochemical deposition of ZnFeS thin film semiconductors on tin oxide substrates. Sol Energy Mater Sol CeUs 37 43-53... 

Evaporation temperature, c Ag atoms flow intensity, isotope method, atoms s l Current carrier concentration variation rate in the film, semiconductor sensor method, Vg- 10 , electrons s Ve... 

Water is involved in most of the photodecomposition reactions. Hence, nonaqueous electrolytes such as methanol, ethanol, N,N-d i methyl forma mide, acetonitrile, propylene carbonate, ethylene glycol, tetrahydrofuran, nitromethane, benzonitrile, and molten salts such as A1C13-butyl pyridium chloride are chosen. The efficiency of early cells prepared with nonaqueous solvents such as methanol and acetonitrile were low because of the high resistivity of the electrolyte, limited solubility of the redox species, and poor bulk and surface properties of the semiconductor. Recently, reasonably efficient and fairly stable cells have been prepared with nonaqueous electrolytes with a proper design of the electrolyte redox couple and by careful control of the material and surface properties [7], Results with single-crystal semiconductor electrodes can be obtained from table 2 in Ref. 15. Unfortunately, the efficiencies and stabilities achieved cannot justify the use of singlecrystal materials. Table 2 in Ref. 15 summarizes the results of liquid junction solar cells prepared with polycrystalline and thin-film semiconductors [15]. As can be seen the efficiencies are fair. Thin films provide several advantages over bulk materials. Despite these possibilities, the actual efficiencies of solid-state polycrystalline thin-film PV solar cells exceed those obtained with electrochemical PV cells [22,23]. 

The rapid developments in the microelectronics industry over the last three decades have motivated extensive studies in thin-film semiconductor materials and their implementation in electronic and optoelectronic devices. Semiconductor devices are made by depositing thin single-crystal layers of semiconductor material on the surface of single-crystal substrates. For instance, a common method of manufacturing an MOS (metal-oxide semiconductor) transistor involves the steps of forming a silicon nitride film on a central portion of a P-type silicon substrate. When the film and substrate lattice parameters differ by more than a trivial amount (1 to 2%), the mismatch can be accommodated by elastic strain in the layer as it grows. This is the basis of strained layer heteroepitaxy. 

Nanocrystalline semiconductor thin film photoanodes, commonly comprised of a three dimensional network of inter-connected nanoparticles, are an active area of photoelectrochemistiy research [78-82] demonstrating novel optical and electrical properties compared with that of a bulk, thick or thin film semiconductor [79,80]. In a thin film semiconductor electrode a space charge layer (depletion layer) forms at the semiconductor-electrolyte interface charge carrier separation occurs as a result of the internal electric... 

Yoko T, Yuasa A, Kamiya K, Sakka S (1991) Sol-gel-derived Ti02 thin film semiconductor electrode for photocleavage of water. J Electrochem Soc 138 2279-2784... 

Nair PK, Nair MTS (1992) Chemically Deposited Zns Thin-Films - Application as Substrate for Chemically Deposited Bi2s3, Cuxs and Pbs Thin-Films. Semiconductor Sci Technol 7 239-244... 

Geinovatch, V.G. Prognostications from the Edge, Microwave 26 (April 1991). Geis, M.W. and J.C. Angus Diamond Film Semiconductors, Sci. Amer., 84 (October 1992). 

Copper electrodes have been used to determine amino acids and carbohydrates [10]. Metal oxide electrodes (including thin-film semiconductors) show some promise, but nothing of substance has yet been published with regard to LCEC. Pulsed amperometric detection (PAD) takes advantage of metal oxides formed in situ. This approach is discussed later. 

We consider a model of a two-probe molecular device which is schematically shown in Fig. 1 where a Ceo molecule is contacted by two semi-infinite gold electrodes [35,36]. One can replace the Ceo by other molecules, atomic clusters, thin films, semiconductors, and other materials. 

Let us quote the text from Ref. [15] "...a, Quantum eraser configuration in which electro-optic shutters separate microwave photons in two cavities from the thin-film semiconductor (detector wall) which absorbs microwave photons and acts as a photodetector, b, Density of particles on the screen depending upon whether a photocount is observed in the detector wall ( yes ) or not ( no ), demonstrating that correlations between event on the screen and the eraser photocount are necessary to retrieve the interference pattern."... 

Kelly, C. A. Meyer, G. J. Excited state processes at sensitized nanocrystalline thin film semiconductor interfaces. Coord. Chem. Rev. 2001, 211, 295-315. 

Copper Conductive films semiconductor devices. Gold Metallization of contacts in semiconductor applications. 

Kaliteevskaya, N.A. Seisyan, R.P. Contrast enhancement in image transfer via interaction of UV radiation with inorganic photoresist films. Semiconductor 2001, 35 (2), 226-229. 

Menezes S., Heller A. and Miller B. (1980), Metal filmed-semiconductor photo-electrochemical cells , J. Electrochem. Soc. 127, 1268-1273. 

Jones T A, Bott B, Hurst N W and Mann B 1983 Solid state gas sensors zinc oxide single crystals and metal phthalocyanine films Proc. Int. Meeting on Chemical Sensors (Analytical Chemistry Symposia Series 17, Fukuoda 1993) ed T Seiyama, K Fueki, J Shiokawa and S Suzuki (New York Elsevier) pp 90-4 Saeki H and Suzuki S 1992 Organic thin film semiconductor device Japanese Patent IPX 19881102 63-277732 US Patent 3 Q19 595 Lewis A 1967 The Palladium Hydrogen System (New York Academic)... 

Takada T. and Komatsu K., O3 gas sensor of thin film semiconductor in In203, in Proc. Transducers 87, Tokyo, Japan, 693, 1987. 

Gurlo A., Barsan N., Ivanovskaya M., Weimar U., and Gopel W., In203 and Mo03-In203 thin film semiconductor sensors Interaction with NO2 and O3, Sens. Actuators B, 47, 92-99,1998. 

Su P.-G., Wu R.-J., and Nieh F.-R, Detection of nitrogen dioxide using mixed tungsten oxide-based thick film semiconductor sensor, Talanta, 59, 667-672, 2003. 

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