Partner: P. Ruterana

CNRS (FR)

Recent publications
1.Maciejewski G., Kret S., Ruterana P., Piezoelectric field around threading dislocation in GaN determined on the basis of high-resolution transmission electron microscopy image, JOURNAL OF MICROSCOPY, ISSN: 0022-2720, Vol.223, pp.212-215, 2006
2.Jurczak G., Maciejewski G., Kret S., Dłużewski P., Ruterana P., Modelling of indium rich clusters in MOCVD InxGa1−xN/GaN multilayers, JOURNAL OF ALLOYS AND COMPOUNDS, ISSN: 0925-8388, DOI: 10.1016/j.jallcom.2004.05.038, Vol.382, No.1-2, pp.10-16, 2004
Abstract:

Chemical composition in a ternary alloy is examined using a quantitative high resolution transmission electron microscopy, finite element modelling of the thin foil relaxation phenomena and microscopy image simulation. The measurement of local lattice distortion on transmission electron microscopy images is a powerful tool for chemical composition determination. However, for the correct interpretation of the results, one needs to take into account the inhomogeneous relaxation of the sample and the strain averaging across the sample. The 3D finite element modelling of such phenomena have been performed as a function of chemical composition and geometry of an indium rich cluster in a MOCVD InxGa1−xN/GaN quantum well. Lattice distortion field measured on: experimental transmission electron microscopy image and simulated one, obtained on the basis of finite element simulation, are compared. This procedure allows an accurate determination of chemical composition in such heterostructures.

Keywords:

Indium clusters, Vapour deposition, Transmissionelectron microscopy, Elasticity, Finite element method, Lattice distortion, Image simulation

Affiliations:
Jurczak G.-IPPT PAN
Maciejewski G.-IPPT PAN
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)
Dłużewski P.-IPPT PAN
Ruterana P.-CNRS (FR)
3.Ruterana P., Singh P., Kret S., Jurczak G., Maciejewski G., Dłużewski P., Cho H.K., Choi R.J., Lee H.J., Suh E.K., Quantitative evolution of the atomic structure of defects and composition fluctuations at the nanometer scale inside InGaN/GaN heterostructures, PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, ISSN: 0370-1972, Vol.241, No.12, pp.2643-2648, 2004
Abstract:

The cover picture of this issue depicts indium composition fluctuations in InGaN/GaN multi quantum wells. The coded color strain distribution (left) was derived from finite element method calculations of the strain relaxation process and high‐resolution transmission electron microscopy (HRTEM) image simulations, superimposed on the HRTEM image of the quantum wells. The possible corresponding shape and εxx strain profiles in the indium rich clusters (right) hint at a concentration close to pure InN in their core. The paper by Pierre Ruterana et al. [1] was presented at the 5th International Symposium on Blue Laser and Light Emitting Diodes (ISBLLED‐2004), held in Gyeongju, Korea, 15–19 March 2004.

Keywords:

HRTEM, quantum well, composition fluctuation, strain distribution

Affiliations:
Ruterana P.-CNRS (FR)
Singh P.-CNRS (FR)
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)
Jurczak G.-IPPT PAN
Maciejewski G.-IPPT PAN
Dłużewski P.-IPPT PAN
Cho H.K.-Dong-A University (KR)
Choi R.J.-Chonbuk National University (KR)
Lee H.J.-Chonbuk National University (KR)
Suh E.K.-Chonbuk National University (KR)
4.Dłużewski P., Jurczak G., Maciejewski G., Kret S., Ruterana P., Nouet G., Finite Element Simulation of Residual Stresses in Epitaxial Layers, Materials Science Forum (MSF), ISSN: 1662-9752, DOI: 10.4028/www.scientific.net/MSF.404-407.141, Vol.404-407, pp.141-146, 2002
Abstract:

A nonlinear finite element approach presented here is based on the constitutive equations for anisotropic hyperelatic materials. By digital image processing the elastic incompatibilities (lattice mismatch) are extracted from the HRTEM image of GaN epilayer. Such obtained tensorial field of dislocation distribution is used next as the input data to the FE code. This approach is developed to study the stress distribution associated with lattice defects in highly mismatched heterostructures applied as buffer layers for the optically active structures.

Keywords:

Dislocations, Anisotropic Hyperelasticity, Residual Stresses

Affiliations:
Dłużewski P.-IPPT PAN
Jurczak G.-IPPT PAN
Maciejewski G.-IPPT PAN
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)
Ruterana P.-CNRS (FR)
Nouet G.-CNRS (FR)

Conference papers
1.Dłużewski P., Belkadi A., Chen J., Ruterana P., Nouet G., FE simulation of InGaN QD formation at the edge of threading dislocation in GaN, IWN 2006, International Workshop on Nitride Semiconductors, 2006-10-22/0-27, Kyoto (JP), DOI: 10.1002/pssc.200674870, Vol.7, pp.2403-2406, 2007
Abstract:

The stress induced diffusion process of In-Ga segregation in InxGa1–xN layer deposited on GaN is simulated step by step by using a 3D nonlinear FE method. From the thermodynamical point of view this process is governed by the driving force induced by the gradient of residual stresses operating in an anisotropic nonlinear elastic structure. The source of stresses we consider is the set of threading dislocations examined in the plane view HRTEM investigation of GaN layer deposited on sapphire.

Affiliations:
Dłużewski P.-IPPT PAN
Belkadi A.-IPPT PAN
Chen J.-Laboratoiré de Recherché sur les Proprietes des Materiaux Nouveaux (FR)
Ruterana P.-CNRS (FR)
Nouet G.-CNRS (FR)
2.Ruterana P., Singh P., Kret S., Cho H.K., Lee H.J., Suh E.K., Jurczak G., Maciejewski G., Dłużewski P., Size and shape of In rich clusters and InGaN QWs at the nanometer scale, IWN 2004, International Workshop on Nitrides Semiconductors, 2004-06-19/06-23, Pittsburgh (US), DOI: 10.1002/pssc.200461463, Vol.2, No.7, pp.2381-2384, 2005
Abstract:

Following the need to accurately understand the In composition fluctuations and their role on the optical properties of the GaN based heterostructures, an investigation of MOCVD InGaN/GaN quantum wells is carried out. To this end, quantitative High Resolution Transmission Electron Microscopy (HRTEM) is coupled with image simulation and Finite Element Method (FEM) for the thin foil relaxation modelling. The results show that 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, in order to help the engineering process of highly efficient devices.

Affiliations:
Ruterana P.-CNRS (FR)
Singh P.-CNRS (FR)
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)
Cho H.K.-Dong-A University (KR)
Lee H.J.-Chonbuk National University (KR)
Suh E.K.-Chonbuk National University (KR)
Jurczak G.-IPPT PAN
Maciejewski G.-IPPT PAN
Dłużewski P.-IPPT PAN