Growth and Characterization of SiGe/SiO<sub>2</sub> Core/Shell Nanocrystals on Insulators
Mansour Aouassa, Mohammed Bouabdellaoui, Walter Batista Pessoa, Isabelle Berbézier, T. Kallel, Thouraya Ettaghzouti, Makram Yahyaoui, K. M. A. Saron, A.K. Aladim, Mohammed Ibrahim, Ibrahim O. Althobaiti
Abstract
In this study, we report the growth and characterization of high-quality SiGe/SiO 2 core–shell nanocrystals on an insulator. Our approach involves the solid-state dewetting of a germanium (Ge) film deposited via molecular beam epitaxy on an ultrathin silicon-on-insulator film. The resulting nanocrystals exhibit exceptional uniformity, a well-defined hemispherical shape, and distinct crystallographic facets, as confirmed by rigorous analyses using advanced techniques, such as high-resolution transmission electron microscopy and energy-dispersive spectrometry. Furthermore, we successfully integrated these SiGe/SiO 2 core/shell nanocrystals into a metal–insulator–semiconductor (MIS) structure. Through current–voltage and impedance spectroscopies, we determine the transport and electrical properties of this integrated system. Our measurements reveal the formation of a Schottky diode with high rectifying behavior. Importantly, impedance measurements allow us to elucidate the equivalent circuit of this MIS structure, highlighting the significant influence of the SiGe/SiO 2 core–shell nanocrystals on the electrical transport phenomena within the MIS architecture. These findings represent a significant advancement in the fabrication and characterization of SiGe/SiO 2 core/shell nanocrystals for MIS devices, opening up exciting possibilities for their applications in photovoltaics and photodetection.