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Accueil du site > Vie du laboratoire > Congrès / Colloques / Conférences > Optical Properties of Individual Nanowires and Quantum Dots in High Magnetic Field, Septembre 2014 > Programme du workshop > Abstract : Correlating structural and optical properties of III-nitride nanowire quantum structures at the single nano-object level

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Abstract : Correlating structural and optical properties of III-nitride nanowire quantum structures at the single nano-object level

Correlating structural and optical properties of III-nitride nanowire quantum structures at the single nano-object level

 

L. Rigutti1, I. Blum1, L. Mancini1, D. Shinde1, D. Hernandez Maldonado1, W. Lefebvre1, J. Houard1, A. Vella1, F. Vurpillot1, B.Deconihout1,G. Jacopin2,3,M. Tchernycheva2, C. Durand4, J. Eymery4, R. Songmuang5, L.F. Zagonel6,7, M. Kociak6

 

1Groupe de Physique des Matériaux, UMR CNRS 6634, University and INSA of Rouen, Normandie University, 76800 St. Etienne du Rouvray, France

2Institut d’Electronique Fondamentale, UMR CNRS 8622, University of Paris Sud 11, 91405 Orsay, France

3 Laboratoire d’Optoélectronique Quantique, École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland

4CEA/CNRS/Université Joseph Fourier, CEA, INAC, SP2M, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France

5CEA-CNRS Group “Nanophysique et Semi-conducteurs”, Institut Néel-CNRS, BP 166, 25 rue des Martyrs, 38042 Grenoble Cedex 9, France

6Laboratoire de Physique des Solides, UMR CNRS 8502, University Paris-Sud XI, 91405 Orsay, France

7Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, SP, Brazil

 

 

The possibility of correlating the structural and optical properties of a given nano-object is of great importance in the domains of research on nanowires and quantum dots. Different microscopic techniques and optical emission spectroscopy can be indeed applied on the same nano-object under study, yielding a remarkable amount of detail and information. This contribution will illustrate two different approaches of correlative microscopy on quantum confining structures in III-nitride nanowires.

 

The first approach is based on the correlation of cathodoluminescence spectroscopy (CL) with nanometer spectral and spatial resolution and high-resolution transmission scanning electron microscopy (HRSTEM) performed on sets of GaN/AlN multi-quantum disc stacks inserted in GaN nanowires during the growth. It becomes thus possible to assign a definite emission energy to each of the quantum discs, even if spatially separated by only a few nm, assessing the effect of size, strain and internal electric fields [1,2].

 

A second approach is based on the correlation of three techniques : micro-photoluminescence spectroscopy (µPL), HR-STEM and atom probe tomography (APT) [3,4]. This approach has been applied on a nano-object containing a portion of radial InGaN/GaN multi-quantum wells extracted from a core-multishell microwire. As a result, the photoluminescence spectra can be interpreted in terms of excitons localizing in quantum dot-like regions within the quantum wells. HR-STEM not only provides information about the crystallography, the presence of extended defects and a 2D characterization of the quantum wells, but it also allows for the best possible APT reconstruction. It is then by APT that the access to the fully resolved 3D structure of the QWs becomes possible, with the evidence for In clustering forming quantum dot-like regions within the quantum wells. The size and composition of these regions well matches with the energy of the emission peaks previously recorded in µPL spectra.

 

 

Schematic illustration of the correlation of micro-photoluminescence, scanning transmission electron microscopy and atom probe tomography on an InGaN/GaN multi-QW system issued from a core-shell micro-wire

References

 

[1] L. F. Zagonel et al., Nano Letters (2011), 11, 568-573

[2] L. F. Zagonel et al., Nanotechnology(2012) 23 455205 

[3] L. Rigutti et al., Ultramicroscopy (2013), 132, 75-80

[4] L. Rigutti et al., Nano letters (2014), 14, 107–114