Thermally oxidized formation of new Ge dots over as-grown Ge dots in the Si capping layer

Abstract

A Si-capped Ge quantum dot sample was self-assembly grown via Stranski-Krastanov mode in a molecular beam epitaxy system with the Si capping layer deposited at 300 C. After annealing the sample in an oxygen atmosphere at 1000 C, a structure, namely two layers of quantum dots, was formed with the newly formed Ge-rich quantum dots embedded in the oxidized matrix with the position accurately located upon the as-grown quantum dots. It has been found that the formation of such nanostructures strongly depends upon the growth temperature and oxygen atmosphere. A growth mechanism was proposed to explain the formation of the nanostructure based on the Ge diffusion from the as-grown quantum dots, Ge segregation from the growing oxide, and subsequent migration/agglomeration.

Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-Tc MnxGe1−x nanomesh

“…As the sample is scaled down to nanoscale, the quantum confinement effect in nanostructures can significantly boost the exchange coupling between the confined holes and the localized Mn11, leading to a higher T c compared with bulk materials11117. Additionally, when it comes to the nanostructure, the ability to accommodate the strain without formation of the lattice defects can be dramatically enhanced due to its large surface3334. In the Mn x Ge 1− x thin film, the lattice strain associated with substitutional Mn can affect and limit the growth of high-quality FMS35; the Mn x Ge 1− x lattice swells up to a critical strain above which Mn atoms segregate into Mn-rich nanocrystals35.…”

Hot-Filament-Assisted Growth of Straight SiOx Nanowires for Optoelectronic Application

“…When colliding with the oxygen, oxidized Ge or Si gas species should be expected. However, a preferential oxidized Si will take place because of the higher binding energy of Si–O relative to the Ge–O . Now, the WO x condensation will act as nuclei to absorb the additional reactive silicon oxide clusters.…”

“…However, a preferential oxidized Si will take place because of the higher binding energy of Si−O relative to the Ge−O. 35 Now, the WO x condensation will act as nuclei to absorb the additional reactive silicon oxide clusters. Because of the low solubility of SiO x in the catalyst, 28 these SiO x clusters slipped to the bottom of the catalyst and penetrated below the catalyst detaching it from the substrate and forming a nanowire, which could be an energetically preferable interface compared with direct contact on the substrate and the catalyst, 28 as illustrated in Figure 4b,c.…”

Quest for high-Curie temperature Mn Ge1− diluted magnetic semiconductors for room-temperature spintronics applications

“…The growth of Mn x Ge 1-x QDs were carried out at 450 °C with Ge growth rate of 0.2 Å/s, abiding by the Stranski-Krastanow (SK) [19] growth mode. Cross-sectional TEM was employed to determine the structural characteristics of the grown Mn x Ge 1-x QDs, as shown in Figure 2(a).…”