•We propose two novel methods, AbStrain and Relative displacement, for the reciprocal space treatment of high-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning ...transmission electron microscopy (HR-STEM) images.•AbStrain allows for quantification and mapping of interplanar distances and angles, displacement fields and strain tensor components with reference to a user-defined Bravais lattice and with their corrections from the image distortions specific to HR-TEM and HR-STEM imaging.•For the case of a crystal composed of two or more types of atoms, we developed a method named “Relative displacement” for extracting sub-lattice fringes associated to one type of atom and measuring atomic columns displacements associated to each sub-structure with reference to a Bravais lattice or to another sub-structure.•The successful application of AbStrain and Relative displacement to HR-STEM images of functional oxide ferroelectric heterostructures is demonstrated.
A method for the reciprocal space treatment of high-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning transmission electron microscopy (HR-STEM) images has been developed. Named “Absolute strain” (AbStrain), it allows for quantification and mapping of interplanar distances and angles, displacement fields and strain tensor components with reference to a user-defined Bravais lattice and with their corrections from the image distortions specific to HR-TEM and HR-STEM imaging. We provide the corresponding mathematical formalism. AbStrain goes beyond the restriction of the existing method known as geometric phase analysis by enabling direct analysis of the area of interest without the need for reference lattice fringes of a similar crystal structure on the same field of view. In addition, for the case of a crystal composed of two or more types of atoms, each with its own sub-structure constraint, we developed a method named “Relative displacement” for extracting sub-lattice fringes associated to one type of atom and measuring atomic columns displacements associated to each sub-structure with reference to a Bravais lattice or to another sub-structure. The successful application of AbStrain and Relative displacement to HR-STEM images of functional oxide ferroelectric heterostructures is demonstrated.
We report room temperature injection lasing in the yellow-orange spectral range (599-605 nm) in (Al
Ga
)
In
P-GaAs diodes with 4 layers of tensile-strained In
Ga
P quantum dot-like insertions. The ...wafers were grown by metal-organic vapor phase epitaxy side-by-side on (811), (211) and (322) GaAs substrates tilted towards the direction with respect to the (100) surface. Four sheets of GaP-rich quantum barrier insertions were applied to suppress leakage of non-equilibrium electrons from the gain medium. Laser diodes having a threshold current densities of ~7-10 kA/cm
at room temperature were realized for both (211) and (322) surface orientations at cavity lengths of ~1mm. Emission wavelength at room temperature ~600 nm is shorter by ~8 nm than previously reported. As an opposite example, the devices grown on (811) GaAs substrates did not show lasing at room temperature.
H and He sequential ion implantation of silicon followed by annealing leads to the formation of gas pressurized cavities. When close enough to the surface, they elastically deform this surface and ...generate blisters. Gaining knowledge of the characteristics and thermal behavior of these blisters is mandatory for the optimization of the Smart Cut™ process. In this paper, we develop the idea and demonstrate that the pressure and the concentrations of the gases inside a blister can be inferred from its actual dimensions and depth location by using simulations based on Finite Element Method (FEM) modelling. We apply this method to initiate a study on the influence of the respective fluences of H and He ions used in a sequential implantation on blistering efficiency.
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•He+H ion implantation followed by annealing generates blisters.•Blisters heights are measured by AFM.•FEM is used to infer gas pressure inside blisters from height measurements.•Gas concentrations are deduced from gas pressure.•It is shown that all implanted He and H pressurize the blisters.
Tuning the band structure and, in particular, gap opening in 1D and 2D materials through their deformation is a promising approach for their application in modern semiconductor devices. However, ...there is an essential breach between existing laboratory scale methods applied for deformation of low-dimensional materials and the needs of large-scale production. In this work, we propose a novel method which is potentially well compatible with high end technological applications: single-walled carbon nanotubes (SWCNTs) first deposited on the flat surface of a supporting wafer, which has been pre-implanted with H+ and He+ ions, are deformed in a controlled and repetitive manner over blisters formed after subsequent thermal annealing. By using resonant Raman spectroscopy, we demonstrate that the SWCNTs clamped by metallic stripes at their ends are deformed over blisters to an average tensile strain of 0.15 0.03%, which is found to be in a good agreement with the value calculated taking into account blister's dimensions. The principle of the technique may be applied to other 1D and 2D materials in perspective.
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The diffusion and interaction of impurity atoms in semiconductors play an important role in modelling of the technological processes for device fabrication. Being mobile, impurity ...atoms, vacancies and interstitials can recombine and/or precipitate in the form of stable complexes which leads to the modification of target material properties. Here, we present an analytic model that predicts the concentrations of such complexes as a function of point defect concentrations using the probabilities for point defects to encounter and the probabilities for the formation of specific complexes dependent on their formation energies. This approach is general and can be used in different systems. We applied this model to the formation of different complexes after H+ implantation in silicon at room temperature. The formation energies of the complexes were calculated using the density functional theory. We linked the macroscopic strain measured in the implanted crystal to the individual deformation fields generated by the different complexes and to their concentrations. Such model calibration allowed determining the diffusion coefficients of silicon vacancies and interstitials at room temperature, the time required for the formation of all the complexes, the concentrations of complexes as a function of H concentration and the specific role of some complexes in generating strain. The model can be extended to the case of the systems co-implanted with different ions and can be applied for developing the SmartCut® technology used for creating innovative substrates.
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