Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 44: Nitrides: Preparation and characterization II
HL 44.8: Vortrag
Donnerstag, 21. März 2024, 16:00–16:15, EW 015
Optical and chemical characterisation of InxGa1−xN layers and nanowire arrays — •Aidan Campbell, Mikel Gómez Ruiz, Jingxuan Kang, Lutz Geelhaar, Oliver Brandt, and Jonas Lähnemann — Paul-Drude-Institut für Festkörperelektronik, Germany
InxGa1−xN is an alloy with promising applications in solar water splitting, CO2 conversion, and solar energy harvesting. Particular advantages are the tunable direct bandgap (0.7–3.5 eV), large absorption coefficient (105 cm−1) and high mobility. In this study, we investigate InxGa1−xN layers of nominal composition 0.025 < x < 0.12 grown by plasma-assisted molecular beam epitaxy. A multi-spectroscopic approach is employed using cathodoluminscence and energy dispersive X-ray spectroscopy in a scanning electron microscope. Thereby, the chemical, optical, and structural properties can be analysed and correlated for the same local region of a specimen. Factors such as dislocation density, luminous intensity, spatial homogeneity of the composition, and the morphology will be discussed, as they are key properties in optimizing growth techniques enabling high efficiency devices. The dislocation density increases by a factor of 6 over this compositional range, reaching 1.5×109 cm−2 at x=0.12. Compositional variations are evidenced by the spatial distribution of emission energies, which for different samples suggest local in-plane variations of Δ x = ± 0.005–0.008. Finally, the investigation is extended to InxGa1−xN nanowires obtained from these layers by top-down processing.
Keywords: InGaN; cathodoluminscence; plasma assisted molecular beam epitaxy; nanowires