The Cooperative Molecular Field Effect

Abstract

Two‐dimensional arrangements of molecules can show remarkable cooperative electronic effects. Such effects can serve to achieve direct electronic sensing of chemical and physical processes via electrostatic effects, i.e., without transfer of charge or matter between the locus of sensing and that of detection.

Molecules on Si: Electronics with Chemistry

“…The effect of a dipolar layer was reviewed by Ishii et al [125] and the importance of the layer's uniformity has been discussed intensively. [112,126,127] Dipolar monolayers can be bound to a variety of inorganic Figure 3. MIS junctions at electronic equilibrium (no applied bias) for three different types of metal with a given semiconductor.…”

“…[113] Not only does depolarization increase with increasing molecular dipole moment, but the preparation of monolayers of highly polar molecules is limited by dipole-dipole repulsion, leading to partial coverage. [112,127,131] However, while the resulting interface will be inhomogeneous, on semiconductors even partial coverage suffices for most of the electrostatic effects [112] because the dipoles control the electric field, which cannot change abruptly.…”

Isomeric effects with di-iodobenzene (C6H4I2) on adsorption on graphite

“…For smaller adsorbates, like N 2 , similar effects are observed [13,14], but the profound differences in substrate interaction tend to obscure the effect of the interface dipole itself. While the effects of the dipole moment along the surface normal are expected [1-3, 15, 16], the possible role of the in-plane dipole, the dipole of the adsorbate parallel with the interface, is far less clear [16].…”

Silicon and Silicon-Related Surfaces for Biosensor Applications

“…The direct covalent linkage (Si-C bond) to the silicon surface provides a well-defined organic monolayer-silicon interface, and the nonpolar character of this strong bond make these monolayers thermally and chemically very robust [Linford, et al, 1995& Sung, et al, 1997. Moreover, because an intervening SiO 2 layer is essentially absent, direct electronic coupling between any organic functionality and the silicon substrate is possible, which provides an opportunity to enhance the device performance compared to SiO 2 -covered electronic devices [Aswal, et al, 2006& Cahen, et al, 2005& Hiremath, et al, 2008& Vilan, et al, 2010. Furthermore, using a semiconductor instead of a metal as a substrate/electrode has the advantage that -depending on the desired electronic properties of the final device -semiconductors with different doping levels and doping types can be used [Boukherroub, 2005& Cahen, et al, 2005.…”

“…Moreover, because an intervening SiO 2 layer is essentially absent, direct electronic coupling between any organic functionality and the silicon substrate is possible, which provides an opportunity to enhance the device performance compared to SiO 2 -covered electronic devices [Aswal, et al, 2006& Cahen, et al, 2005& Hiremath, et al, 2008& Vilan, et al, 2010. Furthermore, using a semiconductor instead of a metal as a substrate/electrode has the advantage that -depending on the desired electronic properties of the final device -semiconductors with different doping levels and doping types can be used [Boukherroub, 2005& Cahen, et al, 2005. As a result organic monolayers on oxide-free silicon have great potential in the field of biosensors, molecular electronics and photovoltaic devices [Har-Lavan, et al, 2009& Maldonado, et al, 2008.…”