Jaime Andres Perez Taborda

By Jaime Andrés Pérez‐Taborda, Olga Caballero‐Calero and Marisol Martín‐González

Silicon and germanium present distinct and interesting transport properties. However, composites made of silicon‐germanium (SiGe) have resulted in a breakthrough in terms of their transport properties. Currently, these alloys are used in different applications, such as microelectronic devices and integrated circuits, photovoltaic cells, and thermoelectric applications. With respect to thermoelectricity, in the last decades, Si0.8Ge0.2 has attracted significant attention as an energy harvesting material, for powering space applications and other industrial applications. This chapter focuses on the recent advances and new approaches in silicon‐germanium (Si1−xGex) nanostructures for thermoelectric devices with high thermoelectric efficiency obtained through magnetron sputtering.

Part of the book: New Research on Silicon

By Daniel A. Triana-Camacho, Jorge H. Quintero-Orozco and Jaime A. Perez-Taborda

The linear theory of piezoelectricity has widely been used to evaluate the material constants of single crystals and ceramics, but what happens with amorphous structures that exhibit piezoelectric properties such as cement-based? In this chapter, we correlate the theoretical and experimental piezoelectric parameters for small deformations after compressive stress–strain, open circuit potential, and impedance spectroscopy on cement-based. Here, in detail, we introduce the theory of piezoelectricity for large deformations without including a functional for the energy; also, we show two generating equations in terms of a free energy’s function for later it will be reduced to constitutional equations of piezoelectricity for infinitesimal deformations. Finally, here is shown piezoelectric and electrical parameters of gold nanoparticles mixed to cement paste: the axial elasticity parameter Y=323.5±75.3kN/m2, the electroelastic parameter γ=−20.5±6.9mV/kN, and dielectric constant ε=939.6±82.9ε0F/m, which have an interpretation as linear theory parameters sijklD, gkij and εikT discussed in the chapter.

Part of the book: Cement Industry