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Open Access Nano Express

Strain Relief Analysis of InN Quantum Dots Grown on GaN

Juan G Lozano1*, Ana M Sánchez1, Rafael García1, Sandra Ruffenach2, Olivier Briot2 and David González1

Author Affiliations

1 Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, 11510, Puerto Real, Cadiz, Spain

2 Groupe d’Etûde des Semiconducteurs, UMR 5650 CNRS, Place Eugène Bataillon, Université Montpellier II, 34095, Montpellier, France

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Nanoscale Research Letters 2007, 2:442-446  doi:10.1007/s11671-007-9080-6

Published: 10 August 2007

Abstract

We present a study by transmission electron microscopy (TEM) of the strain state of individual InN quantum dots (QDs) grown on GaN substrates. Moiré fringe and high resolution TEM analyses showed that the QDs are almost fully relaxed due to the generation of a 60° misfit dislocation network at the InN/GaN interface. By applying the Geometric Phase Algorithm to plan-view high-resolution micrographs, we show that this network consists of three essentially non-interacting sets of misfit dislocations lying along the directions. Close to the edge of the QD, the dislocations curve to meet the surface and form a network of threading dislocations surrounding the system.

Keywords:
Misfit relaxation; Strain mapping; High misfit interface; HRTEM; InN