Strain effect in determining the geometric shape of self-assembled quantum dot
2009 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 42, no 125414Article in journal (Refereed) Published
The geometric shape of a self-assembled quantum dot (QD) formed by the strain-induced Stranski-Krastanov mode has been studied as a function of strain energy by the short-range valence-force-field approach. It has been shown by dynamic bond relaxation through strain energy minimization that for the most commonly used InAs QD in GaAs and InP matrices and Ge QD in Si matrix, a pyramidal shape is energy favoured over an hemispherical shape when the QD is not capped due to the lattice relaxation at the QD surface. When the QD becomes totally embedded in the background material, the elastic strain energy of a hemispherical InAs QD is minimal. The results agree with experimental observations. We further studied the coupling of strain fields of QDs in adjacent QD layers which shows that QDs in multiply stacked QD layers can be aligned along the layer growth direction in order to minimize the strain energy.
Place, publisher, year, edition, pages
2009. Vol. 42, no 125414
VALENCE-FORCE-FIELD; SCANNING-TUNNELING-MICROSCOPY; CHEMICAL-VAPOR-DEPOSITION; OPTICAL-PROPERTIES; LATTICE-DYNAMICS; ATOMIC-STRUCTURE; INAS; GE; STABILITY; LAYERS
IdentifiersURN: urn:nbn:se:kth:diva-11452DOI: 10.1088/0022-3727/42/12/125414ISI: 000266639300052ScopusID: 2-s2.0-70149101762OAI: oai:DiVA.org:kth-11452DiVA: diva2:276195
QC 201007132009-11-112009-11-112012-03-22Bibliographically approved