Contributors: Institut d'électronique fondamentale (IEF); Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS); Groupe de physique des matériaux (GPM); Université de Rouen Normandie (UNIROUEN); Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie); Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA); Université de Caen Normandie (UNICAEN); Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN); Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN); Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie); Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN); Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN); Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS); Ecole Polytechnique Fédérale de Lausanne (EPFL); Laboratoire de photonique et de nanostructures (LPN); Centre National de la Recherche Scientifique (CNRS); GLO AB, Ideon Science Park, Scheelevägen 17, S-223 70 Lund, Sweden; GLO-USA, 1225 Bordeaux Dr, Sunnyvale, CA, 94086, USA; ERC EU project “NanoHarvest” (grant no. 639052); European Project: 639052,NanoHarvest
نبذة مختصرة : International audience ; We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully operational devices allows to probe the electrical properties of the active region with a nanoscale resolution. In particular, the electrical activity of the p-n junction on the m-planes and on the semi-polar planes of individual nanowires is assessed in top view and cross-sectional geometries. The EBIC maps combined with CL characterization demonstrate the impact of the compositional gradients along the wire axis on the electrical and optical signals : the reduction of the EBIC signal toward the nanowire top is accompanied by an increase of the CL intensity. This effect is interpreted as a consequence of the In and Al gradients in the quantum well and in the electron blocking layer, which influence the carrier extraction efficiency. The interface between the nanowire core and the radially grown layer is shown to produce in some cases a transitory EBIC signal. This observation is explained by the presence of charged traps at this interface, which can be saturated by electron irradiation.
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