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Recently synthesized hexagonal group IV materials are a promising platform to realize efficient light emission that is closely integrated with electronics. A high crystal quality is essential to assess the intrinsic electronic and optical properties of these materials unaffected by structural defects. Here, we identify a previously unknown partial planar defect in materials with a type I3 basal stacking fault and investigate its structural and electronic properties. Electron microscopy and atomistic modeling are used to reconstruct and visualize this stacking fault and its terminating dislocations in the crystal. From band structure calculations coupled to photoluminescence measurements, we conclude that the I3 defect does not create states within the hex-Ge and hex-Si band gap. Therefore, the defect is not detrimental to the optoelectronic properties of the hex-SiGe materials family. Finally, highlighting the properties of this defect can be of great interest to the community of hex-III-Ns, where this defect is also present.

In this review paper, several new approaches about the 3C-SiC growth are been presented. In fact, despite the long research activity on 3C-SiC, no devices with good electrical characteristics have been obtained due to the high defect density and high level of stress. To overcome these problems, two different approaches have been used in the last years. From one side, several compliance substrates have been used to try to reduce both the defects and stress, while from another side, the first bulk growth has been performed to try to improve the quality of this material with respect to the heteroepitaxial one. From all these studies, a new understanding of the material defects has been obtained, as well as regarding all the interactions between defects and several growth parameters. This new knowledge will be the basis to solve the main issue of the 3C-SiC growth and reach the goal to obtain a material with low defects and low stress that would allow for realizing devices with extremely interesting characteristics., Funding Agencies|European UnionEuropean Commission [720827]

In this work, the annihilation mechanism of stacking faults (SFs) in epitaxial 3C-SiC layers grown on Si(001) substrates is studied by molecular dynamics (MD) simulations. The evolution of SFs located in the crossing (1̄11) and (11̄1) glide planes is considered. This evolution is determined by the interaction of 30° leading partial dislocations (PDs) limiting the stacking faults under the slightly compressive (∼0.45%) strain condition during the 3C-SiC layer growth. It is characterized in key terms: the distance between the PDs and the mutual orientation of their Burgers vectors. Two SF annihilation scenarios are revealed. In the first scenario, two PDs with opposite screw components of Burgers vectors, leading the SFs located in the (1̄11) and (11̄1) planes, are close enough (∼15 nm or less) and attract each other. As a result, the propagation of both SFs is suppressedviathe formation of a Lomer-Cottrell lock at their intersection. In the second scenario, two PDs are far away one from the other (beyond ∼15 nm) and do not interact, or they repulse each other having equal screw components of their Burgers vectors. In this case, the propagation of only one of the SFs is suppressed. Obtained results explain the mechanism of SF annihilation and formation of SF intersection patterns experimentally observed by TEM investigations. They will provide important implications for the elaboration of advanced methods for the reduction of SF concentrations in epitaxial 3C-SiC layers on Si substrates.

The Data availability statement of this article has been modified to add the accession link to the raw data. The old Data availability statement read “Materials and data that support the findings of this research are available within the paper. All data are available from the corresponding author upon request”. This has been replaced by “Materials and data that support the findings of this research are available within the paper. The raw data have been deposited at https://zenodo.org/record/4589484#.YEoEOy1Y7Sd”. This has been corrected in both the HTML and PDF version of the article.

Recently synthesized hexagonal group IV materials are a promising platform to realize efficient light emission that is closely integrated with electronics. A high crystal quality is essential to assess the intrinsic electronic and optical properties of these materials unaffected by structural defects. Here, we identify a previously unknown partial planar defect in materials with a type I3 basal stacking fault and investigate its structural and electronic properties. Electron microscopy and atomistic modeling are used to reconstruct and visualize this stacking fault and its terminating dislocations in the crystal. From band structure calculations coupled to photoluminescence measurements, we conclude that the I3 defect does not create states within the hex-Ge and hex-Si band gap. Therefore, the defect is not detrimental to the optoelectronic properties of the hex-SiGe materials family. Finally, highlighting the properties of this defect can be of great interest to the community of hex-III-Ns, where this defect is also present.

Strong spin–orbit semiconductor nanowires coupled to a superconductor are predicted to host Majorana zero modes. Exchange (braiding) operations of Majorana modes form the logical gates of a topological quantum computer and require a network of nanowires. Here, we utilize an in-plane selective area growth technique for InSb–Al semiconductor–superconductor nanowire networks. Transport channels, free from extended defects, in InSb nanowire networks are realized on insulating, but heavily mismatched InP (111)B substrates by full relaxation of the lattice mismatch at the nanowire/substrate interface and nucleation of a complete network from a single nucleation site by optimizing the surface diffusion length of the adatoms. Essential quantum transport phenomena for topological quantum computing are demonstrated in these structures including phase-coherence lengths exceeding several micrometers with Aharonov–Bohm oscillations up to five harmonics and a hard superconducting gap accompanied by 2e-periodic Coulomb oscillations with an Al-based Cooper pair island integrated in the nanowire network.

An important issue in the technology of cubic SiC (3C–SiC) material for electronic device applications is to understand the behavior of extended defects such as partial dislocation complexes and stacking faults (SFs). Atomistic simulations using molecular dynamics (MD) are an efficient tool to tackle this issue for large systems at comparatively low computation cost. At this, proper choice of MD potential is imperative to ensure the reliability of the simulation predictions. In this work, we compare the evolution of extended defects in 3C–SiC obtained by MD simulations with Tersoff, analytical bond order, and Vashishta potentials. Key aspects of this evolution are considered including the dissociation of 60° perfect dislocations in pairs of 30° and 90° partials as well as the dependence of the partial dislocation velocity on the Burgers vector and the atomic composition of core. Tersoff potential has been found to be less appropriate in describing the dislocation behavior in 3C–SiC as compared to two other potentials, which in their turn provide qualitatively equivalent predictions. The Vashishta potential predicts much faster defect dynamics than the analytical bond order potential (ABOP). It can be applied therefore to describe the large-scale evolution of the dislocation systems and SFs. On the other hand, ABOP is more precise in predicting local atom arrangements and reconstructions of the dislocation core structures. In this respect, synergetic use of ABOP and Vashishta potential is suggested for the MD simulation study of the properties and evolution of extended defects in the 3C–SiC.

Quality improvement of 3C-SiC material is at present a rapidly growing and intensively exploited field of research. One of the main issues to be solved stems in the high density of extended defects such as dislocations and stacking faults (SFs). The lack of a proper understanding of defects behavior has limited the possibility to overcome these issues. We show that large-scale molecular-dynamics (MD) simulations can strongly help in rationalizing such a complex behavior. After having implemented a script allowing for the insertion of partial dislocation loops within the Large-scale Atomic/Molecular Massively Parallel Simulator LAMMPS [1], we carried out an extensive set of MD simulations based on the Vashista potential [2]. The latter is particularly well suited to investigate defects such as SFs because it allows one to differentiate the energy of SiC hexagonal versus cubic phases. From trajectory analysis we were able to directly observe the evolution of the initial loop, establishing a direct link between its dynamic behavior and the formation of multi-plane SFs in 3C-SiC, therefore shedding light on the formation of such commonly observed defects. In particular we found that an already developed loop locally lowers the energy barriers for the nucleation of another adjacent loop. [1] S. Plimpton, J Comp Phys, 117, 1-19 (1995) [2] P. Vashishta et al., J App Phys, 101, 10 (2007)