Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 58: Poster IIb
HL 58.63: Poster
Dienstag, 8. März 2005, 16:30–19:00, Poster TU F
GaN Nanowhiskers: Epitaxial Growth — •Thomas Richter1, Ralph Meijers1, Raffaella Calarco1, Toma Stoica1,2, and Hans Lüth1 — 1Institute of Thin Films and Interfaces (ISG1) and CNI - Centre of Nanoelectronic Systems for Information Technology, Research Center Jülich, 52425 Jülich, Germany — 2INCDFM, Magurele, POB Mg7, Bucharest, Romania
The study of GaN-based nanostructures, whose electrical and optical characterization is at its infancy, can help to elucidate the link among structural, optical and electrical features, allowing for a deeper understanding of the physical mechanisms controlling the material behavior in these nanostructures.
In our experiments, GaN nanocolumns are reproducibly grown by plasma-assisted molecular beam epitaxy on Si(111). The nanocolumns density and diameter (10-150 nm) are controlled by means of the III/V ratio. The substrate temperature during growth is chosen between 7700C and 8000C. For higher growth temperatures higher Ga fluxes are needed to reach the same growth rate, due to the Ga desorption process. In our experiments we did not change the nominal III/V ratio but the growth temperature, which results in different stoichiometry and deposition rates. The signature of a tapering process can be observed.
The GaN-nanocolumns have been studied and characterized by means of XRD, TEM, Raman spectroscopy, photo- and cathodo- luminescence. A correlation between growth parameter and defects has been found.