Abstract
Capping InAs/GaAs quantum dots (QDs) with a thin GaAsSb layer alters the QDs structural properties, leading to considerable changes in their optical properties. The increase of the Sb content induces a redshift of the emission energies, indicating a change in the buried QDs shape and size. The presence of well-defined ground- and excited-state emission bands in all the photoluminescence spectra allow an accurate estimation of the buried QDs size and shape by numerical evaluation and tuning of the theoretical emission energies. For an Sb content below 14%, the QDs are found to have a type I band alignment with a truncated height pyramidal form. However, for higher Sb content (22%), the QDs are present in a full pyramidal shape. The observed behavior is interpreted in terms of increasing prevention of InAs QDs decomposition with increasing the Sb content in the cap layer.
Highlights
Self-Assembled InAs quantum dots (QDs) have been, to date, a subject of intense research efforts dedicated to exploit their unique properties for diverse innovative applications including, lasers [1], detectors [2]and solar cells [3]
The investigate the effect of Sb content variation on the size and shape of GaAsSb-capped InAs QDs
The correlation between InAs QDs’ numerical simulation and PL experiments has revealed a strong dependence of the buried dots size and shape on the capping layer (CL) Sb content
Summary
Self-Assembled InAs QDs have been, to date, a subject of intense research efforts dedicated to exploit their unique properties for diverse innovative applications including, lasers [1], detectors [2]. For Sb contents (XSb ) lower than 14%, which allow the GaAsSb-capped InAs QDs to have a type I band alignment, the reduction of both strain and decomposition effects, leads to an increased height, longer emission wavelength, and better luminescence efficiency [9,10]. Capping InAs QD with GaAsSb has numerous advantages, including the increase of the QD size as well as tailoring the band lineup, paving the way to novel applications. The investigate the effect of Sb content variation on the size and shape of GaAsSb-capped InAs QDs. The obtained results confirm thethe literature-reported structural investigation andand show thethe ability to gain obtained results confirm literature-reported structural investigation show ability to gain useful information on the buried.
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