The knowledge of local strain fields associated with defects is important for the determination of the local atomic configuration. This is particularly the case in GaN based heterostructures where densities of defects are large, and the correlation between properties and structure needs to be understood. Image processing and image simulations help to extract quantitative information. In this work, we discuss our results on InGaN/GaN quantum wells. For the GaN/InxGa1-xN/GaN QW’s, the mechanism of the light emission is not yet clearly understood. Narukawa et al. suggested that indium rich cluster may help to localise the carriers and will be a centre for radiative recombination. Using pattern recognition on HRTEM images, Kisielowski et al. have shown that the indium may segregate into 1-3 nm diameter areas inside the QW. Ruterana et al., based on a strain distribution extracted from HRTEM images and 2D FEM modelling, pointed out that the In composition fluctuation areas may depend on the growth technique. In this work, two types of samples were investigated, in the first, the measured strain was always high, the thickness of the wells being in the 3-5 nm range. The second set of samples was prepared as pure InN/GaN quantum wells, with thicknesses in the range of a few monolayers, we find that the exctrated local strain does not reflect the nominal composition in these structures and we suggest the origin of the discrepency. In the two types of structures, the In composition fluctuations are clearly pointed out from the HRTEM observations. By a combination of 3D FEM and HRTEM observation, we show that the observed samples exhibit indium composition fluctuation. In many instances, the indium content can reach x=1 in the clusters inside the core. In these MOCVD QWs, we attempt to connect the Quantum dot density, composition, and shape, to the growth conditions.

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2. Hollow nanostructure-assisted growth of GaN by MOCVD and its applications
3. Investigation of InN layers grown by molecular beam epitaxy on Si or GaN templates
4. Structural properties of InAlN thin layers for HEMT applications
5. Low frequency noise measurements in InN films
6. The microstructure and properties of InN layers
7. Role of threading dislocations on Indium distribution in InGaN alloys
8. Optical properties of InN grown on Si(111) substrate
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10. Electronic and magnetic properties of Co-doped ZnO: first principles study
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14. The structure of nucleation Zn(Al)O layers for transparent metal oxide application
15. First-principles calculations of the optical band-gap properties of Mg_1-xZn_xO alloys
16. Theoretical studies of ZnS_1-xO_x alloy band structures
17. FE and MD simulation of InGaN QD formation induced by stress field of threading dislocations
18. Strain Relaxation Effect on the Properties of Ultra Thin ZnO Film on Sapphire (0001) Substrates by Pulsed Laser Deposition
19. Finite element modelling of nonlinear elastic and piezoelectric properties of InN and InGaN QDs
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21. Energy and electronic structure of gallium and nitrogen interstitials in GaN Tilt Boundaries
22. Investigation of InN layers grown by MOCVD and MBE using analytical and high resolution TEM
23. Interfacial diffusion and precipitation in rf magnetron sputtered Mn doped ZnO layers
24. Ultra-thin In-rich InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition
25. The atomic configuration of tilt grain boundaries around <0001> in GaN
26. First principles study of electronic structure of InN and AlN substitution atomic layers embedded in GaN
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