Testing the upper limit of InAs/GaAs self-organized quantum dots density by fast growth rate

We have examined the upper limit of the InAs/GaAs quantum dots (QDs) density by increasing the InAs deposition rate while keeping other growth conditions constant. By changing the InAs deposition rate from 0.1 to 3.6 monolayer/s (ML/s), the relationships between dot size, dot density and InAs deposition rates have been investigated. Nonlinear relationships were observed between dot density, dot size and InAs deposition rates, whereas photoluminescence intensity was found to be linearly dependence on dot density. For a 2.5 ML-thick InAs deposited on GaAs substrates by molecular-beam epitaxy, the highest dot density obtained was 7.8×1011/cm2. This high dot density QDs can be incorporated in device active region to enhance the device optical output.