Structural and optical emission uniformity of m-plane InGaN single quantum wells in core-shell nanorods

Le Boulbar, E mmanuel D. and Edwards, Paul R. and Vajargah, Shahrzad Hosseini and Griffiths, Ian and Gîrgel, Ionut and Coulon, Pierre - Marie and Cherns, David and Martin, Robert W. and Humphreys, C. J. and Bowen, Chris R. and Allsopp, D. W. E. and Shields, P. A. (2016) Structural and optical emission uniformity of m-plane InGaN single quantum wells in core-shell nanorods. Crystal Growth and Design, 16 (4). 1907–1916. ISSN 1528-7483

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    Abstract

    Controlling the long-range homogeneity of core-shell InGaN/GaN layers is essential for their use in light-emitting devices. This paper demonstrates variations in optical emission energy as low as ~7 meV.µm-1 along the m-plane facets from core-shell InGaN/GaN single quantum wells as measured through high-resolution cathodoluminescence hyperspectral imaging. The layers were grown by metal organic vapor phase epitaxy on etched GaN nanorod arrays with a pitch of 2 µm. High-resolution transmission electron microscopy and spatially-resolved energy-dispersive X-ray spectroscopy measurements demonstrate a long-range InN-content and thickness homogeneity along the entire 1.2 μm length of the m-plane. Such homogeneous emission was found on the m-plane despite the observation of short range compositional fluctuations in the InGaN single quantum well. The ability to achieve this uniform optical emission from InGaN/GaN core-shell layers is critical to enable them to compete with and replace conventional planar light-emitting devices.