RT journal article
T1 Formation mechanisms of agglomerations in high-density InAs/GaAs quantum dot multi-layer structures
A1 Ruiz Marín, Nazaret
A1 Fernández de los Reyes, Daniel
A1 Braza Blanco, María Verónica
A1 Flores Gallegos, Sara
A1 Gonzalo, Alicia
A1 Ulloa, Jose María
A1 Ben Fernández, Teresa
A1 González Robledo, David
A2 Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica
K1 Vertical aligned quantum dots
K1 Quantum ring
K1 III-V semiconductors alloys
K1 Composition distribution
K1 Transmission electron microscope
AB The study explores phenomena that occur during the growth of multi-stacked quantum dots (MQD) InAs layers using thin GaAs spacers. An arrangement of plastically relaxed agglomerations that extend along the MQD structure with diameters of about 70–120 nm and separated every 200–400 nm are observed. These agglomerations hinder the regular development of vertically aligned QD columns, leaving only a regular density of QDs in the first layer. The generation of these agglomerations has been modelled based on two extreme cases: (i) conical-like, it presents a more contrasted base and its nucleation is related to the presence of two coalesced QDs. The progression of these agglomerations can be deactivated in the upper layers, probably to a decrease in surface stress as consequence of misfit dislocation formation in the lower layers; (ii) volcano-like, it presents a crater shape due to the collapse of the upper layers with a higher accumulation of In. It is proposed that the origin of this type of agglomerations is due to the formation of a quantum ring (QR) in the first layer. The initial concavity of the QR increases during successive GaAs/InAs deposition cycles as tendency of Ga to out-diffuse rises.
PB North-Holland
SN 0169-4332
YR 2020
FD 2020-01-04
LK http://hdl.handle.net/10498/38897
UL http://hdl.handle.net/10498/38897
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 05-nov-2026