Influence of dopants

Oeter et al. studied in situ FeCIs p-doped o -6T prepared by UHV coevaporation [308]. In line with the observation of new states in the band-gap (compare section 

By Horowitz et al. [338] also the role of oxygen as trap-killer is diseussed. Because the SCLC (see section about I/V-curves) is also much lower in vacuum not only a mere dedoping can be discussed because SCLC is independent of the number of bulk charge carriers. On the other hand the conductivity can also be decreased by an increase of the trap level density. 

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The model clusters were chosen in accordance with the structure of PANI proposed in Refs. [1, 3], The present model of PANI also takes into account that under the influence of dopants (in this particular case, protons and anions (chlorine ions) which form bonds to PANI nitrogen), the spins of the highest occupied molecular orbital (HOMO) become unpaired, and PANI changes to triplet state. It should be noted that only in this state there is a considerable increase in PANI conductivity. 

It is well established, that the poor selectivity of tin-oxide sensors can partly be overcome by adding catalysts to the sensitive layer. Most common additives are noble metals like gold (Au), platinum (Pt) or palladium (Pd). They can be mixed with the tin oxide during paste formation before deposition. The influence of dopants on the gas sensor response is still subject to debates. The two most established mechanisms are the spill-over and the Fermi-level mechanism [82]. 

H. Schaper and L.L. van Reijen, The Influence of Dopants on the Stability of Gamma Alumina Catalyst Supports , Mater. Sci. Monographs, 14 173-76 (1982). 

In conclusion, it seems that for both the AP-CVD and the LP-CVD processes, deposition parameters have been found, for which the introduction of a dopant component does not significantly perturb the crystallographic orientation of the ZnO films. However, it is, at this stage, not possible to identify the mechanisms and critical parameters governing the influence of dopants on film structure. Nevertheless, some speculative statements can be made in the case of the AP-CVD process, the deposition temperature seems to be the critical factor, i.e., above 400°C the growth orientation of ZnO films is no more perturbed by the introduction of a dopant. For the LP-CVD... 

H. Seidel, L. Csepregi, A. Heuberger, and H. Baumgartel, Anisotropic etching of crystalline silicon in alkaline solutions. II Influence of dopants, J. Electrochem. Soc, 137, 3626, 1990. 

It has been demonstrated in earlier sections that the catalytic activity of nickel oxide in the room-temperature oxidation of carbon monoxide is related to the number and the nature of the lattice defects on the surface of the catalyst and that any modification of the surface structure influences the activity of the solid. Changes of catalytic activity resulting from the incorporation of altervalent ions in the lattice of nickel oxide may, therefore, be associated not only with the electronic structure of the semiconductor (principle of controlled valency ) (78) but perhaps also with the presence of impurities in the oxide surface or a modification of the surface structure because of this incorporation. In order to determine the influence of dopants on the lattice defects in the surface of the solid and on its catalytic activity, doped nickel oxides were prepared under vacuum at a low temperature (250°). Bulk doping is not achieved and, thence, one of the basic assumptions of the electronic theory of catalysis (79) is not fulfilled. 

Fig. 28 is efficient in the prediction of the effect of cations, as we verified, a posteriori, for In and La. It explains the influence of dopant nature, temperature and initial specific surface area. 

There are only very few investigations about the influence of dopants on the geometric structure and in particular on the exact position of the counter-ions in the doped materials. Most of these investigations are of a theoretical nature with all known uncertainties. 

D. Andreeva, M. Kantcheva, I. Ivanov, L. Ilieva, J. W. Sobczak, W. Lisowskic, Gold supported on ceria doped by Me " (Me = Al and Sm) for water gas shift reaction influence of dopant and preparation method, Catal. Today 158 (2010) 69-77. 

Seidel H, Csepregi L, Heuberger A, Baumgartel H (1990) Anisotropic etching of crystalline silicon in alkaline solutions II influence of dopants. J Electrochem Soc 137(ll) 3626-3632... 

Application To discover new catalytic materials To improve known catalytic systems, to study influence of dopants and modifiers, to study deactivation, to measure kinetics... 

Practical utilization of GST materials depends upon a substantial optical or electrical contrast between the amorphous and crystalline phases. As both the resistivity and optical absorption depend upon the electronic structures of materials, it is necessary to investigate the influence of dopants on the electronic structure of the host network. 

To observe the influence of dopants on the optical properties of Ge2Sb2Tes, we computed the dielectric functions of the pure and doped Ge2Sb2Tes. Figure 19.5 presents the imaginary and real part of the dielectric functions of pure and doped Ge2Sb2Tes in both the amorphous and the crystalline phases. Figure 19.5 confirms that the addition of Ag or Au does not affect the optical properties strongly,... 

Table 4.1. Influences of dopants on stoichiometric binary solids...

Sudarsanam P, Mallesham B, Reddy PS, et al. Nano-Au/Ce02 catalysts for CO oxidation Influence of dopants (Fe, La and Zr) on the physicochemical properties and catalytic activity. Appl Catal B Environ. 2014 144 900-8. 

The influence of dopant nature, composition and structural peculiarities of doped ATLS on their transport properties has been revealed. The composite cathode and anode materials... 

Fi > Influence of dopant (AsF, Iodine) and of confirmation (cis, trans) on the temperature dependence of the micro-wave conductivity (Ref.lO)... 

In addition to the influence of dopant in the nanocomposites, the increase of conductivity associated with the incorporation of nanoparticles can be due to other factors. Core-shell structures were fabricated with FesOa nanoparticles of 4 nm as core and PPy as shell [19]. The augment of the polymer content up to 36 % provokes a change of morphology from spherical to tubular, that could be the reason of the conductivity enhancement in comparison with the PPy without nanoparticles, from 10.1 to 59.4 S/cm. In the same way, nanocomposites of PPy functionalized with p-TSA and Fe203 nanoneedles show very high conductivity, 65 S/cm [8]. 

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