Negative differential resistance

On the other hand, some work on the topic considers the presence of negative differential resistance in the current-voltage characteristics and the possibility of a coulomb... 

According to the literature [21], all reported electrochemical oscillations can be classified into four classes depending on the roles of the true electrode potential (or Helmholtz-layer potential, E). Electrochemical oscillations in which E plays no essential role and remains essentially constant are known as strictly potentiostatic (Class I) oscillations, which can be regarded as chemical oscillations containing electrochemical reactions. Electrochemical oscillations in which E is involved as an essential variable but not as the autocatalytic variable are known as S-NDR (Class II) oscillations, which arise from an S-shaped negative differential resistance (S-NDR) in the current density (/) versus E curve. Oscillations in which E is the autocatalytic variable are knovm as N-NDR (Class III) oscillations, which have an N-shaped NDR. Oscillations in which the N-NDR is obscured by a current increase from another process are knovm as hidden N-NDR (HN-NDR Class IV) oscillations. It is known that N-NDR oscillations are purely current oscillations, whereas HN-NDR oscillations occur in both current and potential. The HN-NDR oscillations can be further divided into three or four subcategories, depending on how the NDR is hidden. 

Switzer, J. A., Maune, B. M., Raub, E. R. and Bohannan, E. W. (1999) Negative differential resistance in electrochemicaDy self-assembled layered nanostructures. J. Phys. Chem. B, 103, 395-398. 

Among the two-terminal devices that can be imagined for UE [capacitors, inductors, rectifiers, negative differential resistance (NDR) devices], the simplest is a molecular wire, that is, a molecule capable of conducting electricity a nanoconductor or, equivalently, a nanoresistor. Even the most conductive of molecular wires has a minimum resistance. 

Chen J, Reed MA, Rawlett AM, Tour JM (1999) Large on-off ratios and negative differential resistance in a molecular electronic device. Science 286 1550-1552... 

In addition and importantly, even in non-active junctions, when the electrode Fermi level matches the molecular bridge energy levels, resonance phenomena can generate electrical behaviours similar to those of conventional electronic devices, such as rectification [86-89] and negative differential resistance (NDR) [90, 91]. 

Wassel RA, Credo GM, FuiererRR, Feldheim DL, Gorman CB (2004) Attenuating negative differential resistance in an electroactive self-assembled monolayer-based junction. J Am Chem Soc 126 295-300... 

Le JD, He Y, Hoye TR, Mead CC, Kiehl RA (2003) Negative differential resistance in a bilayer molecular junction. Appl Phys Lett 83 5518... 

Molecular Rectifiers and Negative Differential Resistance Devices. 234... 

Figure 12. Synthetic route to a molecular device that bears functionality for electron capture. This nitroaniline exhibits negative differential resistance.

Lyo, I. W., and Avouris, Ph. (1989). Negative differential resistance on the atomic scale Implications for atomic scale devices. Science 245, 1369-1371. 

In Fig. 4.3.3b we present a V — I curve with a turning point and a negative differential resistance region with current saturation, computed for the same values of parameters Ni, A, cq as in Fig. 4.3.3a. This V—I curve corresponds to the upper and the middle solution branches. The range of parameters in which the high current solutions exist is again evaluated below, via an asymptotic treatment for /— oo. 

Stability of the described solution branches (the middle branch with negative differential resistance is expected to be unstable). 

In 1999 large ON-OFF ratios and negative differential resistance (NDR) were measured in molecular electronic devices constructed using functionalized OPEs and a nanopore test... 

D. B. Neal, M. I. Newton, and G. McHale, Negative differential resistance in thin metal films with a cadmium arachidate overlayer, Int. J. Electronics 76,771—775 (1994). 

The donor-acceptor substituted OPE 26 is particularly interesting since it shows a high negative differential resistance (see below). The original synthesis reported by Tour et al. [13c] was in some respects inconvenient and therefore Bryce and coworkers [13f] developed an improved procedure. The details are given in the original literature. Scheme 10.8 show the final step in the synthesis of 26, the coupling between alkyne 27 and iodide 1 [13f. ... 

Besides the potential-dependent adsorption of a poison, i.e. a species that is different from the electroactive species or current carrier, other mechanisms are discussed that may hide a region of negative differential resistance and thus give rise to oscillations on a branch of the I-U curve with positive slope. According to specific mechanistic features, a subdivision of HN-NDR oscillators was proposed into originally three subclasses [12]. 

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