Impedance Spectroscopy
537
capacitance. The interface capacitance gives more information about the semiconductor. Using equation given by Nicollia and Goetzberger [77], wave function can
be calculated which facilitates the determination of important electrical properties of
the semiconductor. The impedance data can also be used to extract additional information about the states of interface and their related time constants. IS is capable of
measuring very low interface state concentrations (less than 10
15 m
−2 (eV)
−1 ) [78].
IS is very advantageous since it is able to extract interfacial information in detail
which is not possible by using other measurement techniques.
4.5 Solid Electrolyte Chemical Sensors
IS plays an immense role in the fabrication and characterization of solid electrolyte
chemical sensors (SECS). SECS are electrochemical sensors which can be utilized
to measure the pressure or concentration of chemical species in liquids or gases.
IS is an excellent method for investigating the critical parameters which govern the
performance of the electrode and electrolytes in this type of sensors. This technique
is used to scrutinize the effect of different electrode materials at temperatures less
than 600 °C on the characteristics of zirconia-based oxygen sensors [79]. IS has been
applied by many researchers to study the effect of various electrode materials and
pretreated temperatures on the performance of oxygen sensors at lower temperatures
[80]. The impedance of the electrode is significantly affected by temperature and
exposure time. Therefore, IS measurements can be used in optimizing the temperature
and sintering times in order to give an electrode with effective properties.
4.6 Photo Electrochemical Solar Cells
The devices which can harness solar energy and convert it into chemical or electrical
energy by process of electrochemical reaction at an interface are called photo electrochemical solar cells [81]. These devices consist of a semiconductor-electrolyte
interface with a suitable redox couple in solution. IS can examine the presence of
surface states or other variations in the semiconductor electrolyte interface. Several
authors have thoroughly investigated the impedance response of many different interfaces that are technologically important [82]. IS helps in modeling the semiconductor
electrolyte interface and can probe the physics of these interfaces in the solar cells.
The potential to be applied can be controlled allowing significant understanding of
the important parameters of the device. Complete analysis of the operation of device
for the entire desired frequency spectrum can be performed by help of IS.
537
capacitance. The interface capacitance gives more information about the semiconductor. Using equation given by Nicollia and Goetzberger [77], wave function can
be calculated which facilitates the determination of important electrical properties of
the semiconductor. The impedance data can also be used to extract additional information about the states of interface and their related time constants. IS is capable of
measuring very low interface state concentrations (less than 10
15 m
−2 (eV)
−1 ) [78].
IS is very advantageous since it is able to extract interfacial information in detail
which is not possible by using other measurement techniques.
4.5 Solid Electrolyte Chemical Sensors
IS plays an immense role in the fabrication and characterization of solid electrolyte
chemical sensors (SECS). SECS are electrochemical sensors which can be utilized
to measure the pressure or concentration of chemical species in liquids or gases.
IS is an excellent method for investigating the critical parameters which govern the
performance of the electrode and electrolytes in this type of sensors. This technique
is used to scrutinize the effect of different electrode materials at temperatures less
than 600 °C on the characteristics of zirconia-based oxygen sensors [79]. IS has been
applied by many researchers to study the effect of various electrode materials and
pretreated temperatures on the performance of oxygen sensors at lower temperatures
[80]. The impedance of the electrode is significantly affected by temperature and
exposure time. Therefore, IS measurements can be used in optimizing the temperature
and sintering times in order to give an electrode with effective properties.
4.6 Photo Electrochemical Solar Cells
The devices which can harness solar energy and convert it into chemical or electrical
energy by process of electrochemical reaction at an interface are called photo electrochemical solar cells [81]. These devices consist of a semiconductor-electrolyte
interface with a suitable redox couple in solution. IS can examine the presence of
surface states or other variations in the semiconductor electrolyte interface. Several
authors have thoroughly investigated the impedance response of many different interfaces that are technologically important [82]. IS helps in modeling the semiconductor
electrolyte interface and can probe the physics of these interfaces in the solar cells.
The potential to be applied can be controlled allowing significant understanding of
the important parameters of the device. Complete analysis of the operation of device
for the entire desired frequency spectrum can be performed by help of IS.