Phase-field modeling of the morphological evolution of ringlike structures during growth: Thermodynamics, kinetics, and template effects

Donno, Marcello De; Albani, Marco; Bergamaschini, Roberto; Montalenti, Francesco

doi:10.1103/physrevmaterials.6.023401

Cited by 3 publications

(2 citation statements)

References 38 publications

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“…Their nonpolar versions ({1230} and {1320}) according to the GaN Wulff plot should be faster growing than even a-planes which "sit" in local minima [21] while maxima correspond roughly to these two families of nonpolar planes. These nonpolar planes are predicted to be typical for the growth of wurtzite materials in apertures, [22] and have been reported previously for wurtzite InP nanostructures. [23] So, the appearance of expectedly fast-growing semipolar versions of these planes in our μ-holes is not completely surprising.…”

Section: Semipolar Facet Formationsupporting

confidence: 77%

Surface Morphology Evolution of AlGaN Microhoneycomb Structures during Epitaxial Overgrowth

Singh,

Zubialevich,

Parbrook

2024

Physica Status Solidi (b)

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The surface morphological development during epitaxial overgrowth of AlGaN on microhoneycomb (μ‐HC) patterned relaxed AlGaN/AlN/sapphire templates is studied. Optimization of μ‐pattern design and influence of various growth parameters are carried out in search for conditions resulting in coalescence of μ‐HC structures into planar layers or ordered arrays of V‐pits with well‐defined crystallographic facets. It is found that in a wide range of growth conditions, formation of V‐pits with semipolar facets occurs where their crystallographic orientation is defined by the geometry of the initial μ‐HC patterns and growth conditions. High‐temperature and high V/III ratio conditions are found to favor c‐plane expansion and allow recovery of planarity on the patterned templates. Systematic study of surface morphology evolution in conditions favoring 1) semipolar facets formation and 2) coalescence is carried out and possible mechanisms underpinning the observed behaviors have been proposed.

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Section: Semipolar Facet Formationsupporting

confidence: 77%

Surface Morphology Evolution of AlGaN Microhoneycomb Structures during Epitaxial Overgrowth

Singh,

Zubialevich,

Parbrook

2024

Physica Status Solidi (b)

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“…The elastic constants of crystals with hexagonal symmetry are well known to be in-plane isotropic, meaning for example the components of Young's modulus in the a ⟨ 11 20 ⟩ and m ⟨ 10 10 ⟩ crystal directions should be identical. One reason for the observed symmetry could be the etching process, which, in a reversal of the effect seen in anisotropic growth rates [12], could result in a non-circular mesa and an anisotropic strain field; we see no evidence for this in the electron image of figure 1, though. It may instead be the case that the relaxation (and therefore expansion) of material around the mesa perimeter has resulted in a subtle 'buckling' of the epilayer, giving 6-fold periodically alternating regions of different azimuthal normal strain.…”

Section: Discussionmentioning

confidence: 61%

Simultaneous mapping of cathodoluminescence spectra and backscatter diffraction patterns in a scanning electron microscope

Edwards,

Naresh Kumar,

McKendry

et al. 2024

Nanotechnology

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Electron backscatter diffraction and cathodoluminescence are complementary scanning electron microscopy modes widely used in the characterisation of semiconductor films, respectively revealing the strain state of a crystalline material and the effect of this strain on the light emission from the sample. Conflicting beam, sample and detector geometries have meant it is not generally possible to acquire the two signals together during the same scan. Here, we present a method of achieving this simultaneous acquisition, by collecting the light emission through a transparent sample substrate. We apply this combination of techniques to investigate the strain field and resultant emission wavelength variation in a deep-ultraviolet micro-LED. For such compatible samples, this approach has the benefits of avoiding image alignment issues and minimising beam damage effects.

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Selective area epitaxy of in-plane HgTe nanostructures on CdTe(001) substrate

Chaize,

Baudry,

Jouneau

et al. 2024

Nanotechnology

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Semiconductor nanowires are believed to play a crucial role for future applications in electronics, spintronics and quantum technologies. A potential candidate is HgTe but its sensitivity to nanofabrication processes restrain its development. A way to circumvent this obstacle is the selective area growth technique. Here, in-plane HgTe nanostructures are grown thanks to selective area molecular beam epitaxy on a semi-insulating CdTe substrate covered with a patterned SiO2 mask. The shape of these nanostructures is defined by the in-plane orientation of the mask aperture along the <110>, <1-10>, or <100> direction, the deposited thickness, and the growth temperature. Several micron long in-plane nanowires can be achieved as well as more complex nanostructures such as networks, diamond structures or rings. A good selectivity is achieved with very little parasitic growth on the mask even for a growth temperature as low as 140°C and growth rate up to 0.5 ML/s. For <110> oriented nanowires, the center of the nanostructure exhibits a trapezoidal shape with {111}B facets and two grains on the sides, while <1-10> oriented nanowires show {111}A facets with adatoms accumulation on the sides of the top surface. Transmission electron microscopy observations reveal a continuous epitaxial relation between the CdTe substrate and the HgTe nanowire. Measurements of the resistance with four-point scanning tunneling microscopy indicates a good electrical homogeneity along the main NW axis and a thermally activated transport. This growth method paves the way toward the fabrication of complex HgTe-based nanostructures for electronic transport measurements.

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Phase-field modeling of the morphological evolution of ringlike structures during growth: Thermodynamics, kinetics, and template effects

Cited by 3 publications

References 38 publications

Surface Morphology Evolution of AlGaN Microhoneycomb Structures during Epitaxial Overgrowth

Surface Morphology Evolution of AlGaN Microhoneycomb Structures during Epitaxial Overgrowth

Simultaneous mapping of cathodoluminescence spectra and backscatter diffraction patterns in a scanning electron microscope

Selective area epitaxy of in-plane HgTe nanostructures on CdTe(001) substrate

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