The electric field is not the only factor determining charge flow in a material, and different materials naturally develop electric potential differences at equilibrium ( Galvani potentials ).
12.
An ITIES system is said " polarised " if the distribution of the different charges and redox species between the two phases determines the Galvani potential difference.
13.
However, if one or both of the capacitor plates is a semiconductor, then galvani potential is " not " necessarily the only important contribution to capacitance.
14.
Thus, the Galvani potential difference is determined entirely by chemical difference of the two phases; specifically by the difference of the chemical potential of the charge carriers in the two phases.
15.
These excited electrons diffuse, and some reach the rectifying junction ( usually a p-n junction ) where they are accelerated into a different material by a built-in potential ( Galvani potential ).
16.
The Galvani potential difference between an electrode and electrolyte ( or between other two electrically conductive phases ) forms in an analogous fashion, although the chemical potentials in the equation above may need to include all species involved in the electrochemical reaction at the interface.
17.
For example, a p-n junction in equilibrium, there is a galvani potential ( built-in potential ) across the junction, but the " voltage " across it is zero ( in the sense that a voltmeter would measure zero voltage ).
18.
The Evanohm family of nickel-chrome alloys [ Ni72Cr20Mn4Al3Si1 ], [ Ni73Cr20Cu2Al2Mn1Si ], have high resistance, low temperature coefficient of resistance, low electromotive force ( Galvani potential ) when in contact with copper, high tensile strength, and also are very stable with regards to heat treatment.
19.
An ITIES is said " polarisable " if one can change the Galvani potential difference, or in other words the difference of inner potentials between the two adjacent phases, without noticeably changing the chemical composition of the respective phases ( i . e . without noticeable electrochemical reactions taking place at the interface ).
