Continuous wavelength tuning of InAs quantum dots on InP [formula omitted] and [formula omitted] substrates by chemical-beam epitaxy

Abstract

The growth of InAs quantum dots (QDs) on InP (1 0 0) and (3 1 1) A substrates by chemical-beam epitaxy is studied. The InAs QDs are embedded in a GaInAsP layer lattice-matched to InP. We demonstrate an effective way to continuously tune the emission wavelength of InAs QDs grown on InP (1 0 0) . With an ultra-thin GaAs layer inserted between the QD layer and the GaInAsP buffer, the peak wavelength from the InAs QDs can be continuously tuned from above 1.6 μm down to 1.5 μm at room temperature. The major role of the thin GaAs layer is to greatly suppress the As/P exchange during the deposition of InAs and subsequent growth interruption under arsenic flux, as well as to consume the segregated In layer floating on the GaInAsP buffer. Moreover, it is found that InP (3 1 1) A substrates are particularly promising for formation of uniform InAs QDs. The growth of InAs on InP (3 1 1) A consists of two stages: nanowire formation due to strain-driven growth instability and subsequent QD formation on top of the wires. The excellent size uniformity of the InAs QDs obtained on InP (3 1 1) A manifests itself in the narrow photoluminescence line width of 26 meV at 4.8 K .