Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 32: Nitrides: Preparation and Characterization I
HL 32.4: Vortrag
Mittwoch, 19. März 2025, 10:15–10:30, H15
Accessing and evaluating the full growth window of PAMBE grown AlGaN/GaN nanowires — •Rudolfo Hötzel1, Marten Wilkens1, Florian Krause1, Andreas Rosenauer1,2, Stephan Figge1, and Martin Eickhoff1,2 — 1Institute of Solid State Physics, University of Bremen, 28359 Bremen, Germany — 2MAPEX Center for Materials and Processes, 28359 Bremen, Germany
Typically group III/V nanowires synthesized by PAMBE are grown under a surplus of nitrogen. Under metal-rich conditions nanowire broadening is reported [1] leading to increased coalescence until self-stabilisation to stoichiometric conditions is reached. To establish stoichiometry single GaN nanowires consisting of multilayers of GaN grown with varying Ga fluxes were analyzed by STEM-EDX. The dependence of growth rates on temperature and fluxes could be consistently fitted with previously reported growth models [1] with the Ga desorption rate as the only free parameter. However a lateral broadening was not observed even for deep Ga-rich conditions. We attribute this to higher growth temperatures leading to an increased Ga desorption from the side facets. Based on these findings AlGaN/GaN nanowires were grown under deep metal-rich conditions. We observed that high Al/Ga fluxes lead to the formation of AlN regions due to the higher formation enthalpy of AlN with Ga accumulating on the c-face because of demixing. A homogenous incorporation of Al under deep metal-rich conditions was only possible for low Al/Ga flux ratios which are limited by the growth temperature. [1] S. Fernández-Garrido et al., Nano Lett. 13, 3274-3280 (2013)
Keywords: Nanowire; PAMBE; AlGaN; GaN