Solid state electronic conductivity

One current-based approach is referred to as impedancemetric sensing [32]. This is based on impedance spectroscopy, in which a cyclic voltage is applied to the electrode and an analysis of the resultant electrical current is used to determine the electrode impedance. As different processes have different characteristic frequencies, impedance spectroscopy can be used to identify and separate contributions from different processes, such as electron transfer at the interface from solid-state electronic conduction. The frequency range ofthe applied voltage in impedancemetric sensors is selected so that the measured impedance is related to the electrode reaction, rather than to transport in the electrode or electrolyte material. Thus, the response is different from that in resistance-based sensors, which are related to changes in the electrical conductivity of a semiconducting material in response to changes in the gas composition. 

Two-electrode cells have also been used in measurements of the solid-state electronic conductivity of nanoparticles and other materials. A typical cell is a concentric tubular structure with an inner dimension on the order of a few mm where a pair of disk-shaped electrodes can be plugged in and sandwich the electrol)de confined within a tubular interior (Figure 2.2). To maintain good contact between the electrode and the electrolyte, the two electrodes have to be pressed in where the interelectrode distance can be accurately... 

Solid-State Electronic Conductivity of Nanoparticle Ensembles..179... 

SOLID-STATE ELECTRONIC CONDUCTIVITY OF NANOPARTICLE ENSEMBLES... 

Ghosh, D., Chen, S. W. Solid-state electronic conductivity of rathenium nanoparticles passivated by metal-carbon covalent bonds. Chem Phys Lett 2008, 465, 115-119. 

The complicated topic of solid-state electrical conductivity is well described in Solid State Chemistry and its Applications, A. R. West, Wiley, Chichester, 1984, although it does not explicitly discuss sensors. Those wanting more depth should look at Transition Metal Oxides, P. A. Cox, Clarendon Press, Oxford, 1992, which provides a readable account of the conduction of ions and electrons through solids. 

Solid-state electronic devices such as diodes, transistors, and integrated circuits contain p-n junctions in which a p-type semiconductor is in contact with an n-type semiconductor (Fig. 3.48). Because solar radiation can excite electrons into a conduction band, semiconductors can be used to generate an electrical current by the action of sunlight. 

A CP film is deposited on a split electrode, making a bridge between the two parts. By tuning the potential of the film with respect to a reference electrode, the doping level, and thus the conductivity of the film, is controlled. Hence, the drain current can be controlled by the gate voltage. The feasibility of such transistors has been demonstrated, but they are still far from competitive with silicon technology, in particular due to the slowness of electrochemical (ionic) processes compared to solid-state electronics. 

C. T. Sah, "The Equivalent Circuit Model in Solid-State Electronics III. Conduction and Displacement Currents," Solid-State Electronics, 13 (1970) 1547-1575. 

Metalloids show some properties that are characteristic of both metals and nonmetals. Many of the metalloids, such as silicon, germanium, and antimony, act as semiconductors, which are important in solid-state electronic circuits. Semiconductors are insulators at lower temperatures, but become conductors at higher temperatures (Section 13-17). The conductivities of metals, by contrast, decrease with increasing temperature. 

Carbon electronics started from the investigation of diamond single crystals (sp -type hybridization) because the diamond crystal structure is similar to that of Si and Ge. It was expected that both p- and n-type doping could be achieved in diamond to obtain the basic element of solid-state electronics that is, the p-n junction. However, the conductivity of only the p-type was realized in diamond and it was the main obstacle to the creation of carbon electronics. Nevertheless, there is an alternative route to the creation of hetero-junctions by use of the highly oriented sp -hybridized carbon films doped by different elements. 

These materials are characterized by common techniques such as H NMR, IR, elemental analysis, DSC, and TGA.54 58 59 60 64 68 Other techniques such as electron spin resonance (ESR),54 magnetic susceptibilities54 and Mossbauer spectroscopy (when they apply),56,58 60 64 71 uV-visible spectroscopy,58,59 60 61 64-67 and solid-state electric conductivity measurements5456 59-63 66 67 71 were also employed. These materials were carefully compared to model bis(mono-isocyanide) adducts for better understanding of the physical properties. Important solubility problems are often observed when no alkyl side chain is used. So, these more soluble substituents are incorporated either on the macrocycles or the bridging ligands for better characterization. 

Semiconductors are used extensively in solid-state electronic devices and computers. The majority of materials for these applications are based on doped silicon. An important property ofp-re junctions is that they allow electron flow only from the re side to thep side. Such one-way devices are called diodes. Consider Figure 2c again. If a positive voltage (also called a forward bias) is applied that lowers the energy barrier between re and p, then the electrons in the conduction band on the re side can flow across the junction (and holes can flow from p to re). A reverse bias, however, raises the height of the barrier and increases the charge separation at the junction, impeding any flow of electrons from p to re. 

The primary objective of this paper is to illustrate by specific examples from our past and current research how electrical property measurements can be of value in deducing information regarding the solid-state electronic structure and in studying intermolecular orbital interactions in such transition metal complex systems. To facilitate this discussion, a brief description of electrical conductivity and some other electrical properties is included. For a more detailed account as well as for a description of the various experimental techniques which are used to determine these properties, the reader is referred to any of several excellent books on the subject (12,13). 

A. G. Guy, Calculation of activity coefficients of conduction electrons in metals and semiconductors, Solid State Electron. 26 (1983) 433-436. 

The solution electronic spectrum exhibits live absorptions whose positions and intensities are a function of concentration and pH, suggesting interaction in solution as well as in the solid state (157). Conductivity measurements have not been reported for the platinum blue substance, but since there is no evidence for partial oxidation the material is not expected to show a high conductivity. 

The packing density of the constituent atoms in the interior regions of protein molecules is, on average, equivalent to that of most organic compounds in the crystalline state. As such, it is possible to consider that membrane proteins may exhibit some of the solid-state electronic properties which have been extensively studied in elemental amorphous materials and organic polymers. Such properties include electronic conduction via localized and delocalized electronic states. When localized states are... 

Good solid-state electronic and Li ionic conductivities for higher rate performance... 

Other substitutions (by different atoms and to different degrees) change the conductivity of silicon in other ways, and it is this variable conductivity that is the basis for all solid-state electronics. This intentional introduction of defects is called doping. In addition to silicon, other materials—properly doped—can be used as semiconductors. Some of these materials are 1 1 combinations of p and p valence shell atoms (Si has a p valence shell, so on average the atoms have a silicon-like valence shell). GaAs and InAs are common materials that are also used for semiconductors. 

Ionic conductivity is electrical conductivity due to the motion of ionic charge. Elementary science introduces this phenomenon as a property of liquid electrolyte solutions. In the solid state, ionic conductivity has recently been somewhat overshadowed by electronic, but nevertheless was recognized by Faraday, who observed electrical conductivity in solid lead fluoride at high temperature. The conductivity in this case was due to the motion of fluoride anions within the structure. This type of conductivity in solids has long been of fundamental interest as well as being applied in the interpretation of corrosion. More recently, applications have been found in energy conversion devices and chemical sensors. ... 

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