Related papers: Raman spectroscopy and strain mapping in individua…
We present a first-principles study on lattice vibrational modes of Si/Ge core-shell nanowires (NWs). In addition to quantum confinement, the internal strain induced by the lattice mismatch between core and shell contributes to significant…
Strain engineering in semiconductor nanostructures offers a promising route to optimize electronic and optical properties for advanced quantum technologies. This study explores the relationship between core and shell thicknesses and strain…
Recent advances in nanowire synthesis have enabled the realization of crystal phases that in bulk are attainable only under extreme conditions, i.e. high temperature and/or high pressure. For group IV semiconductors this means access to…
We report on the behavior of Ge-Ge, Ge-Sn, Sn-Sn like and disorder-activated vibrational modes in GeSn semiconductors investigated using Raman scattering spectroscopy. By using an excitation wavelength close to E1 gap, all modes are clearly…
Strain engineering in Sn-rich group IV semiconductors is a key enabling factor to exploit the direct band gap at mid-infrared wavelengths. Here, we investigate the effect of strain on the growth of GeSn alloys in a Ge/GeSn core/shell…
We investigated the electronic properties of strained Si/Ge core-shell nanowires along the [110] direction using first principles calculations based on density-functional theory. The diameter of the studied core-shell wire is up to 5 nm. We…
Core-shell nanowires made of Si and Ge can be grown experimentally with excellent control for different sizes of both core and shell. We have studied the structural properties of Si/Ge and Ge/Si core-shell nanowires aligned along the…
GeSn alloys are the subject of intense research activities as these group IV semiconductors present direct bandgap behaviors for high Sn contents. Today, the control of strain becomes an important challenge to improve GeSn devices. Strain…
The strain configuration induced by the lattice mismatch in a core-shell nanowire is calculated analytically, taking into account the crystal anisotropy and the difference in stiffness constants of the two materials. The method is applied…
Strained nanowires with varying InAs/InP core-shell thicknesses were grown using Chemical Beam Epitaxy. Microphotoluminescence spectroscopy, performed at low temperature, was then used to study the optical properties of single wires.…
Strain modulated electronic properties of Si/Ge core-shell nanowires along [110] direction were reported based on first principles density-functional theory calculations. Particularly, the energy dispersion relationship of the…
The great possibilities for strain engineering in core/shell nanowires have been explored as an alternative route to tailor the properties of binary III-V semiconductors without changing their chemical composition. In particular, we…
We study theoretically the low-energy phonons and the static strain in cylindrical core/shell nanowires (NWs). Assuming pseudomorphic growth, isotropic media, and a force-free wire surface, we derive algebraic expressions for the dispersion…
Ge$_{1-x}$Sn$_{x}$ alloys are a promising candidate material to realise direct-gap group-IV semiconductors for applications in Si-compatible electronic and photonic devices. Here, we present a combined theoretical and experimental analysis…
We investigate the strain state of ensembles of thin and nearly coalescence-free self-assembled GaN nanowires prepared by plasma-assisted molecular beam epitaxy on Ti/Al$_{2}$O$_{3}(0001)$ substrates. The shifts of Bragg peaks in…
Ge under high strain is predicted to become a direct bandgap semiconductor. Very large deformations can be introduced using microbridge devices. However, at the microscale, strain values are commonly deduced from Raman spectroscopy using…
Misfit strain in core-shell nanowires can be elastically released by nanowire bending in case of asymmetric shell growth around the nanowire core. In this work, we investigate the bending of GaAs nanowires during the asymmetric overgrowth…
Ge/Si(001) multilayer heterostructures containing arrays of low-temperature self-assembled Ge quantum dots and very thin Si$_x$Ge$_{1-x}$ layers of varying composition and complex geometry have been studied using Raman spectroscopy and…
We preform large-scale \emph{ab initio} density functional theory calculations to study the lattice strain and the vibrational properties of colloidal semiconductor core-shell nanoclusters with up to one thousand atoms (radii up to…
The authors study the elastic deformation field in lattice-mismatched core-shell nanowires with single and multiple shells. The authors consider infinite wires with a hexagonal cross section under the assumption of translational symmetry.…