Electrical characterisation and analysis of dominant contributions in disordered semiconducting systems with an application to the pure bentonite material for civil engineering applications

Abstract

Semiconductors and clay materials have significant applications in environmental, civil engineering and optoelectronic sectors. The application of an electric field to such systems is subject of many works. However, to understand the behaviour of such materials under the influence of an electric field, the perception of its electrical properties is essential. In the present study, the powerful technique of complex impedance spectroscopy (CIS) is introduced to illustrate the electrical characteristics of two types of disordered semiconducting materials. These are Cu5In9Se16, an ordered defect compound of the I-III-VI2 family and a novel bentonite clay system which is an insulator at room temperature and semiconductor above 400 °C. Na-bentonite has been studied extensively because of its strong adsorption capacity and complexation ability while Cu5In9Se16 is considered for its use in solar and phtovoltaique domain. Some of selenides have turned out to be leading materials for electro-optical devices and the tellurides for thermoelectric power generation. It is very likely that study of bentonite clay and other similar materials may lead to the technology of heterojunction and clay composite. The frequency dependence of conductivity of bentonite was investigated using an impedance analyzer in the frequency range (20 Hz–1 MHz). The experimental data of CIS are analyzed using some analytical methods that take into account the effect of the grains and grain boundaries. The impedance data confirm the non-Debye behavior in these systems. Some important parameters related to the identified dominant contribution such as relaxation time and activation energies are estimated for the studied materials in the considered temperature and frequency ranges

Geotechnical and thermal analysis and complex impedance spectroscopy characterization of pure Moroccan bentonite material for civil engineering applications

“…Different temperature and frequency spectra display different features, resulting in varied applications for analysis of the data and reveal useful information about the electrical properties of different structures, e.g., grain, grain boundary and electrode/sample contact [1]. In our previous study on Cu 5 In 9 Se 16 [2] and Fe 2 O 3 /Kaolinite [3] ceramics, the powerful technique of complex impedance spectroscopy (IS) is described in order to illustrate the electrical characteristics of some representative disordered semiconducting materials in different temperature ranges from -175 °C to +700 °C. Analytical methods using the second derivative of ln(−Z″) and ln(M″) and first derivative of the function Beta = arctan (−Z″/Z′) were presented to identify the dominant microscopic contributions to the electrical conduction [2].…”

“…In our previous study on Cu 5 In 9 Se 16 [2] and Fe 2 O 3 /Kaolinite [3] ceramics, the powerful technique of complex impedance spectroscopy (IS) is described in order to illustrate the electrical characteristics of some representative disordered semiconducting materials in different temperature ranges from -175 °C to +700 °C. Analytical methods using the second derivative of ln(−Z″) and ln(M″) and first derivative of the function Beta = arctan (−Z″/Z′) were presented to identify the dominant microscopic contributions to the electrical conduction [2]. In this paper, frequency-domain responses in impedance and modulus are discussed in detail, taking a pure bentonite Moroccan clay ceramics as an example.…”

“…Remarkable agreement are found between simulated results and measured data. In general, clays are considered as the most interesting materials because of their low cost and their abundance over all continents [2,3]. Their small size in natural conditions (less than 2 μm) means that these minerals develop large specific surfaces [4].…”