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Chery N, Ngo TH, Chauvat MP, Damilano B, Courville A, DE Mierry P, Grieb T, Mehrtens T, Krause FF, Müller-Caspary K, Schowalter M, Gil B, Rosenauer A, Ruterana P. The microstructure, local indium composition and photoluminescence in green-emitting InGaN/GaN quantum wells. J Microsc 2017; 268:305-312. [PMID: 29023712 DOI: 10.1111/jmi.12657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 11/26/2022]
Abstract
In this work, we analyse the microstructure and local chemical composition of green-emitting Inx Ga1-x N/GaN quantum well (QW) heterostructures in correlation with their emission properties. Two samples of high structural quality grown by metalorganic vapour phase epitaxy (MOVPE) with a nominal composition of x = 0.15 and 0.18 indium are discussed. The local indium composition is quantitatively evaluated by comparing scanning transmission electron microscopy (STEM) images to simulations and the local indium concentration is extracted from intensity measurements. The calculations point out that the measured indium fluctuations may be correlated to the large width and intensity decrease of the PL emission peak.
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Affiliation(s)
- N Chery
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
| | - T H Ngo
- Laboratoire Charles Coulomb, Batiment 21, Campus Triolet, Université de Montpellier, Montpellier, France
| | - M P Chauvat
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
| | - B Damilano
- Université Côte d'Azur, CRHEA, CNRS, France
| | | | | | - T Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - T Mehrtens
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - F F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - K Müller-Caspary
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - M Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - B Gil
- Laboratoire Charles Coulomb, Batiment 21, Campus Triolet, Université de Montpellier, Montpellier, France
| | - A Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - P Ruterana
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
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Keller AF, Coull JA, Chery N, Poisbeau P, De Koninck Y. Region-specific developmental specialization of GABA-glycine cosynapses in laminas I-II of the rat spinal dorsal horn. J Neurosci 2001; 21:7871-80. [PMID: 11588160 PMCID: PMC6763841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
The spinal dorsal horn is the first level of the CNS in which nociceptive input from sensory afferents is integrated and transmitted. Although inhibitory control in this region has a crucial impact on pain transmission, the respective contribution of GABA and glycine to this inhibition remains elusive. We have previously documented co-release of GABA and glycine at the same inhibitory synapse in spinal laminas I-II of adult rats [older than postnatal day 30 (P30)]. However, despite this co-release, individual miniature inhibitory postsynaptic currents (mIPSCs) were mediated by either glycine receptors (GlyR) or GABA(A) receptors (GABA(A)R), yet never by the two together. In contrast, recent studies of ventral horn immature inhibitory synapses (</=P21) reported individual mIPSCs that were mediated by both GABA(A)Rs and GlyRs. This raises the question of whether mixed mIPSCs are present in immature lamina I-II neurons yet are lost through a maturation-dependent synaptic specialization. To test this, we recorded mIPSCs using patch-clamp techniques in lamina I-II neurons in spinal slices taken at different stages of development. We found that, in neurons younger than P23, both GlyR-only and GABA(A)R-only mIPSCs could be recorded, in addition to mixed GABA(A)R-GlyR mIPSCs. With maturation however, both lamina I-II neurons gradually discontinued exhibiting mixed mIPSCs, although with differing patterns of specialization. Yet, at all developmental stages, benzodiazepine administration could unmask mixed mIPSCs. Together, these findings indicate that, although GABA and glycine are continually co-released throughout development, junctional codetection ceases by adulthood. This indicates an age-dependent postsynaptic tuning of inhibitory synapses that occurs in a region-specific manner.
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Affiliation(s)
- A F Keller
- Laboratoire de Neurophysiologie Cellulaire et Intégrée, Centre National de la Recherche Scientifique Unité Mixte de Recherche 7519, Université Louis Pasteur, 67084 Strasbourg cedex, France
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