Activation Mechanism of the Cyclic Switchover Effect …
637
anode process [11, 24]. The experiments with distilled water as a liquid medium in
which dendritic copper point contacts were successfully created [4, 12] confirm this
assumption. The high chemical potential of the copper nanostructure caused an easy
transition of copper atoms from the metallic lattice into the liquid phase followed
by hydration. As a result, the near-surface layer of the conduction channel became
enriched with charge carriers necessary for the efficient functioning of GES.
The obtained results shed light on one of the aspects of the high efficiency of the
new mechanism of selective detection in gases and liquid media which is based on
the quantized electric conductance of dendritic Yanson point contacts and the cycle
switchover effect [3, 4]. Besides the quantized growth and quantized conductance
displayed in the cyclic switchover effect, dendritic Yanson point contacts possess the
whole set of properties typical of the surface of newly formed nanosized structures.
The tip of the dendritic point contact in all phases of the cyclic process is a fresh
nanostructure with elevated free surface energy. The high level of energy is caused
by the two main factors: the size effect and the specific features of juvenile interfaces
[27, 28]. The fundamental trend of a system to lower its free energy is responsible
for the high adsorptive capacity of the surface which results in a higher probability
of effective interaction between these structures and the analyte and eventually in the
formation of new physical or chemical bonds. Since these processes occur simultaneously with the quantum transformations in the dendritic Yanson point contacts
during their synthesis, they provide additional opportunities for the new quantum
mechanism of selective detection [4]. As a result, quantum point-contact sensors are
a priori characterized not only by the virtually absolute selectivity but also by an
enhanced sensitivity to liquid and gaseous analytes.
4 Summary
The present paper analyzes the experimental data on the dynamics of electric conductance and lifetime of dendritic Yanson point contacts during the cyclic switchover
effect and studies the peculiarities of the processes that can enable the realization
of the quantum mechanism of selective detection and lead to an enhanced sensitivity of point-contact sensors to liquid and gaseous analytes. A mathematical model
is proposed for the anode destruction of copper point contacts during the cyclic
switchover process. The GES concept allowed us to logically correctly determine
the localization of the sections where conduction channel destruction takes place
and use the basic equation of electrochemical kinetics as the basis for calculations in
the case of the rate-determining step of electronic transition. It is shown that a GES
in an electric field function as a system with a positive feedback, which determines
the dynamics of the point-contact resistance variation in an ion-conducting medium.
Taking into account the key influence of the Faraday processes on the mechanism
of the nanostructure destruction, we find a correlation between the duration of the
anode reaction and the linear dimensions of the conduction channel. All calculations are performed for Yanson point contacts [1, 2], with their main fundamental
637
anode process [11, 24]. The experiments with distilled water as a liquid medium in
which dendritic copper point contacts were successfully created [4, 12] confirm this
assumption. The high chemical potential of the copper nanostructure caused an easy
transition of copper atoms from the metallic lattice into the liquid phase followed
by hydration. As a result, the near-surface layer of the conduction channel became
enriched with charge carriers necessary for the efficient functioning of GES.
The obtained results shed light on one of the aspects of the high efficiency of the
new mechanism of selective detection in gases and liquid media which is based on
the quantized electric conductance of dendritic Yanson point contacts and the cycle
switchover effect [3, 4]. Besides the quantized growth and quantized conductance
displayed in the cyclic switchover effect, dendritic Yanson point contacts possess the
whole set of properties typical of the surface of newly formed nanosized structures.
The tip of the dendritic point contact in all phases of the cyclic process is a fresh
nanostructure with elevated free surface energy. The high level of energy is caused
by the two main factors: the size effect and the specific features of juvenile interfaces
[27, 28]. The fundamental trend of a system to lower its free energy is responsible
for the high adsorptive capacity of the surface which results in a higher probability
of effective interaction between these structures and the analyte and eventually in the
formation of new physical or chemical bonds. Since these processes occur simultaneously with the quantum transformations in the dendritic Yanson point contacts
during their synthesis, they provide additional opportunities for the new quantum
mechanism of selective detection [4]. As a result, quantum point-contact sensors are
a priori characterized not only by the virtually absolute selectivity but also by an
enhanced sensitivity to liquid and gaseous analytes.
4 Summary
The present paper analyzes the experimental data on the dynamics of electric conductance and lifetime of dendritic Yanson point contacts during the cyclic switchover
effect and studies the peculiarities of the processes that can enable the realization
of the quantum mechanism of selective detection and lead to an enhanced sensitivity of point-contact sensors to liquid and gaseous analytes. A mathematical model
is proposed for the anode destruction of copper point contacts during the cyclic
switchover process. The GES concept allowed us to logically correctly determine
the localization of the sections where conduction channel destruction takes place
and use the basic equation of electrochemical kinetics as the basis for calculations in
the case of the rate-determining step of electronic transition. It is shown that a GES
in an electric field function as a system with a positive feedback, which determines
the dynamics of the point-contact resistance variation in an ion-conducting medium.
Taking into account the key influence of the Faraday processes on the mechanism
of the nanostructure destruction, we find a correlation between the duration of the
anode reaction and the linear dimensions of the conduction channel. All calculations are performed for Yanson point contacts [1, 2], with their main fundamental