Scientific Results

GaSb quantum dot morphology for different growth temperatures and the dissolution effect of the GaAs capping layer

Year: 2010

Authors: Kamarudin M. Ahmad, Hayne M., Zhuang Q.D., Kolosov O., Nuytten T., Moshchalkov V.V., Dinelli F.

Autors Affiliation: Department of Physics, Lancaster University, Lancaster LA1 4YB, UK; INPAC-Institute for Nanoscale Physics and Chemistry, Pulsed Fields Group, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium; CNR-Istituto per lo Studio dei Materiali Nanostrutturati, Via P. Gioberti 101, I-40129 Bologna, Italy

Abstract: We compare the characteristics of GaSb quantum dots (QDs) grown by molecular beam epitaxy on GaAs at temperatures from 400 to 490 degrees C. The dot morphology, in terms of size, shape and density, as determined by atomic force microscopy (AFM) on uncapped QDs, was found to be highly sensitive to the growth temperature. Photoluminescence (PL) spectra of capped QDs are also strongly dependent on growth temperature, but for samples with the highest dot density, where the QD luminescence would be expected to be the most intense, it is absent. We attribute this to dissolution of the dots by the capping layer. This explanation is confirmed by AFM of a sample that is thinly capped at 490 degrees C. Deposition of the capping layer at low temperature resolves this problem, resulting in strong QD PL from a sample with a high dot density.

Journal/Review: JOURNAL OF PHYSICS D-APPLIED PHYSICS

Volume: 43 (6)      Pages from: 065405  to: 065405

More Information: This work was supported by the Engineering and Physical Sciences Research Council (grant number EP/H006419), in the framework of the QD2D project; the Royal Society Brian Mercer Feasibility Award; and the Belgian IAP. MH acknowledges support of the Research Council, UK, and MAK thanks the Universiti Putra Malaysia and the Ministry of Higher Education, Malaysia.
KeyWords: MOLECULAR-BEAM EPITAXY; ANTIMONY EXCHANGE; SURFACE; GASB(001); ISLANDS
DOI: 10.1088/0022-3727/43/6/065402

Citations: 19
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