Growth and Characterization of SiGe/SiO2 Core/Shell Nanocrystals on Insulators

In this study, we report the growth and characterization
of high-quality SiGe/SiO2 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/SiO2
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/SiO2 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/SiO2 core/shell nanocrystals for MIS devices, opening up
exciting possibilities for their applications in photovoltaics and photodetection.