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HL: Fachverband Halbleiterphysik

HL 64: GaN: Preparation and Characterization III

HL 64.4: Vortrag

Mittwoch, 28. März 2012, 17:15–17:30, EW 202

Pulsed growth of InN and Ga_1−xIn_xN with large x by MBE — •Andreas Kraus, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Technische UniversitätBraunschweig, Institut für Angewandte Physik, Mendelssohnstraße 2, 38106 Braunschweig

High In content GaInN is still a material which gains much attention due to its outstanding optical and electrical properties. Because of the large lattice mismatch and differences in bond strength to nitrogen high quality material is very hard to achieve.
To get a deeper understanding of the growth kinetics of this material system, InN and GaInN layers were grown on GaN templates by radio frequency molecular beam epitaxy using a pulsed growth mode. The approximately 100 nm thick InN layers were sequentially grown in 352 periods of c₀/2 In and N followed by a few seconds where only nitrogen reaches the surface. Hereby the time of nitridation was varied. The growth was monitored in-situ by reflection high energy electron diffraction and by optical reflectometry as well as ex-situ by atomic force microscopy and high resolution X-ray diffraction. Comparing the samples grown with different nitridation times during every In pulse, the samples with the longest nitridation time exhibit best structural quality in terms of XRD rocking widths and surface roughness measured by atomic force microscopy.
The results of these experiments were used to realize Ga_1−xIn_xN layers with x≈0.9. Also superlattice structures, where nominally 2 nm GaN are followed by c₀/2 InN, were grown. However, XRD analysis reveals that instead of pure InN, Ga_1−xIn_xN with x ≈ 0.3 is obtained.