Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 96: GaN: Growth and doping

HL 96.3: Vortrag

Freitag, 15. März 2013, 10:00–10:15, H15

Island nucleation during double pulsed growth of InN with RF-MBE — •Andreas Kraus, Uwe Rossow, Heiko Bremers, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig

Although InN is predicted to have outstanding material properties the data obtained experimentally are more or less disappointing. In particular the carrier mobility is much lower than predicted. Since the growth of InN is very difficult, this discrepancy is most likely due to the low quality of the investigated material. Recently, the quality of MBE-grown InN has been improved by applying pulsed source fluxes. In our recent work we presented a double-pulsed growth method, where periodically the equivalent of less than one monolayer In is followed by a distinct time of nitridation. With this method a surface morphology made of huge and atomically flat grains (≈ 2 µm in diameter) was achieved.

To get a deeper understanding of this growth behavior a series of samples with various numbers of periods was grown. The growth was monitored in-situ by reflection high energy electron diffraction and by optical reflectometry. Ex-situ the samples were characterized by atomic force microscopy, scanning electron microscopy and high resolution X-ray diffraction.

At small period numbers only little islands with dendritic features at their boundaries are visible. These grains evolve to the huge ones that were observed previously. If the period number is large enough that the grains meet each other, they coalesce to a closed surface.