RT journal article
T1 Role of Sb on the vertical-alignment of type-II strain-coupled InAs/GaAsSb multi quantum dots structures
A1 Ruiz Marín, Nazaret
A1 Fernández de los Reyes, Daniel
A1 Braza Blanco, María Verónica
A1 Flores Gallegos, Sara
A1 Stanojevic, Lazar
A1 Gonzalo, Alicia
A1 Utrilla, Antonio
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 GaAsSb capping layer
K1 III-V semiconductors alloys
K1 Composition distribution
K1 Transmission electron microscopy
AB The implementation of GaAs0.8Sb0.2 as CL to obtain type-II strain-coupled InAs MQD structures has been examined and compared to similar structures without Sb or without strain coupling. First, it has been demonstrated that capping with GaAsSb prevents the formation of In-rich agglomerations that hampered the QD formation as it has been observed in the sample without Sb. Instead, it promotes the vertical alignment (VA) of almost all QDs with a high density of QD columns. Second, there is a preferential Sb accumulation over the dots together with an undulation of the growth front, contrary to the observed in the uncoupled structure. In case of a deficient covering of GaAsSb, as occurs for giant QDs, In-rich agglomerations may develop. Each VAQD column consists of a sequence of alternating quantum blocks of pyramid-shaped In(Ga)As separated by GaAsSb blocks that rest over them. These Sb-rich blocks are not homogeneous accumulating around the pyramidal apex like a collar. Between the columns, there is an impoverishment of In and Sb compared to the uncoupled sample. These columns can behave as self-aligned nanowires with type II band alignment between self-assembled InAs and GaAsSb quantum blocks that opens new opportunities for novel devices.
PB Elsevier
SN 1873-4669
YR 2020
FD 2020-08-15
LK http://hdl.handle.net/10498/38890
UL http://hdl.handle.net/10498/38890
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 07-nov-2026