Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster: Nitrides
HL 31.2: Poster
Montag, 31. März 2014, 17:00–20:00, P2
The role of Si during the growth of GaN micro- and nanorods — •Christian Tessarek1, Martin Heilmann1, Christel Dieker2, Erdmann spiecker2, and Silke Christiansen1,3 — 1Max Planck Institute for the Science of Light, Erlangen — 2University Erlangen-Nuremberg, Center for Nanoanalysis and Electron Microscopy, Erlangen — 3Helmholtz Centre Berlin for Materials and Energy, Berlin
Self-assembled GaN micro- and nanorods on sapphire substrates have been grown by metal-organic vapor phase epitaxy via a self-catalyzed vapor-liquid-solid (VLS) growth mode [1]. The aspect ratio/vertical growth of the rods is strongly dependent on the Si/Ga ratio. Furthermore, Si improves the rod morphology and rods with a regular hexagonal shape, smooth sidewall facets and sharp edges are obtained. Whispering gallery modes are observed in optical investigations representing the high quality of the rods [2].
Structural investigations have been carried out utilizing transmission electron microscopy and energy dispersive X-ray spectroscopy. A SiN layer is existing on the sidewall facets of the GaN rods. The SiN layer acts as an antisurfactant for GaN and is thus stabilizing the sidewall facets. The influence of the SiN layer on the thermal resistivity and on the subsequent InGaN quantum well growth will be discussed. Finally, a model will be presented explaining the role of Si during the VLS GaN rod growth [3].
[1] C. Tessarek et al., J. Appl. Phys. 114, 144304 (2013). [2] C. Tessarek et al., Opt. Express 21, 2733 (2013), and Jpn. J. Appl. Phys. 52, 08JE09 (2013). [3] C. Tessarek et al., Cryst. Growth Des., submitted.