Effects of growth conditions on the formation of self-assembled InAs quantum dots grown on (1 1 5)A GaAs substrate

Effects of growth conditions on the formation of InAs quantum dots (QDs) grown on GaAs (1 1 5)A substrate were investigated by using the reflection high-energy electron diffraction (RHEED) and photoluminescence spectroscopy (PL). An anomalous evolution of wetting layer was observed when increasing the As/In flux ratio. This is attributed to a change in the surface reconstruction. PL measurements show that QDs emission was strongly affected by the InAs deposited amount. No obvious signature of PL emission QDs appears for sample with 2.2 ML InAs coverage. Furthermore, carrier tunneling from the dots to the non-radiative centers via the inclination continuum band is found to be the dominant mechanism for the InAs amount deposition up to 4.2 MLs.

Graphical abstractAn abnormal evolution of θc as a function of the flux ratio (As/In) was attributed to a change in the surface reconstruction of GaAs (1 1 5)A. Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Influence of growth temperature and As/In flux ratio on the wetting layer properties was investigated. ► Abnormal dependence of wetting layer thickness by increasing the As/In flux ratio. ► Effects of InAs amount deposition on the dynamic of carriers were discussed. ► Tunneling effect via piezoelectric field is found to be the dominant mechanism at high temperature.