Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 49: Quantum dots: preparation and characterization
HL 49.8: Vortrag
Freitag, 27. März 2009, 12:15–12:30, BEY 81
Volmer-Weber growth of InN quantum dots by MOVPE — •Christian Meißner1,2, Simon Ploch1, Markus Pristovsek1, and Michael Kneissl1 — 1Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, EW6-1, 10623 Berlin — 2ISAS - Institute for Analytical Sciences, Albert-Einstein-Str. 9, 12489 Berlin
We have investigated the growth of uncapped InN quantum dots (QDs) on GaN. The indium nitride QDs were grown on GaN/sapphire templates in a horizontal metal-organic vapour phase epitaxy reactor (MOVPE) at 100 mbar in a N2 atmosphere. At a temperature of 520∘C the growth time was varied between 5 s and 60 s. The precursor partial pressures were 0.5 Pa trimetylindium (TMIn) and 2500 Pa ammonia respectively. The InN material deposition during growth was investigated with in-situ spectroscopic ellipsometry (SE) and ex-situ with atomic force microscopy (AFM) as well as X-ray diffraction (XRD).
A linear increase of the effective layer thickness, i. e. a constant growth rate of InN, was observed. At smallest growth time the surface is covered by only 0.9 ML of InN but still exhibits quantum dots with a density of 7·1010 cm−2 indicating Volmer-Weber growth mode. Further growth shows coalescence at a growth time beyond 20 s, with 50 nm in diameter and 4.9 nm high nanostructures. This diameter is consistent with the calculated coalescence diameter of 51 nm for the observed density of 7·1010 cm−2.