Metal oxides semiconductor properties

In a series of transition metal oxide semiconductor powders, photochemical activity in the decarboxylation of oxalic acid was controlled by surface properties and the presence of recombination centers, which in turn depended on the preparation method Similar effects have also been noted in the photodecarboxylation of pyruvic acid and formic acid... 

Metal oxide semiconductor field effect transistors (MOSFETs) constitute other materials with applicability in the development of biosensors. Usually, a MOSFET structure consists of a metal gate on top of an oxide layer, tyqjically Si02 [189]. The catalytic properties of these sensors depend upon the type of the gate metal as well as the temperature at which the MOSFET is operated. The most used catalytic metals used as gate materials are Pd (is a good... 

D. Schmidt, H. Niimi, B. J. Hinds, D. E. Aspnes, and G. Lucovsky, New approach to preparing smooth Si(lOO) surfaces Characterization hy spectroellipsometry and validation of Si/Si02 interface properties in metal-oxide-semiconductor devices, J. Vac. Sci. Technol. B14(4), 2812, 1996. 

A wide range of physical parameters are suitable for chemical sensing applications, consequently, there is a very wide variety of different transducers. Some examples of frequent transducing techniques are metal oxide semiconductor devices (MOS diodes and field effect transistors) relying e.g. on changes in electrical fields or opt(r)odes concerning optical phenomena such as absorbance and fluorescence, but also miniaturised capacities [1]. Mass-sensitive, or acoustic, devices constitute another very popular class of transducers. Within this chapter we will focus on this transducing technique and introduce its abihties and properties in combination with selective artificial interaction materials. 

Thermal oxidation of the two most common forms of single-crystal silicon carbide with potential for semiconductor electronics applications is discussed 3C-SiC formed by heteroepitaxial growth by chemical vapour deposition on silicon, and 6H-SiC wafers grown in bulk by vacuum sublimation or the Lely method. SiC is also an important ceramic ana abrasive that exists in many different forms. Its oxidation has been studied under a wide variety of conditions. Thermal oxidation of SiC for semiconductor electronic applications is discussed in the following section. Insulating layers on SiC, other than thermal oxide, are discussed in Section C, and the electrical properties of the thermal oxide and metal-oxide-semiconductor capacitors formed on SiC are discussed in Section D. 

Consider that atoms have a size range of about 1-2 A. Most inorganic solids, with the exception of halides, sulfides (and other pnictides), are based upon the oxygen atom, i.e.- oxide = O", whose atomic radius does not change even when sulfates, phosphates and silicates are formed. Oxide has an atomic diameter of 1.5 A or 0.15 nm. = 0.00015 (om. Nanoparticles are clumps of 1000 to 10,000 atoms. The latter would be a particle of 0.15 (om. in diameter. They can be metal oxides, semiconductors, or metals with novel properties useful for electronic, optical, magnetic and/or catalytic uses. 

ZnO is being regarded as one of the important metal oxide semiconductors for future applications. Since its chemical and physical properties are highly dependent on composition and shape (defects), reliable methods are necessary to ensure control over the latter. The heterocubane (MeZnO Pr)4 was shown to be a suitable organometallic precursor for gas-phase CVS and solid-state synthesis of nanoscaled Interestingly, highly... 

Recently, organic conducting polymers have become the focus of much of the materials research in chemosensing devices. Synthetic flexibility allows the chemical and physical properties of polymers to be tailored over a broad range of values for any given application. In addition, polymers exhibit tunable specificity to volatile organic compounds, which makes them ideal candidates for replacing canonical sensor materials such as metal oxide semiconductors. 

Metal oxides represent an important class of materials with a variety of technological applications. In general, transition metal oxides are vital for a series of technologies, such as solar cells and Li ion batteries. Several reports in the literature describe the effects of size on the various properties of this class of materials. Nanocrystalline metal oxide semiconductors such as Ti02, Sn02 and ZnO, for example, display... 

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