Low size dispersion of inas quantum islands emitting at 1.55/spl mu/m on InP [001]

We show that the size dispersion of InAs/InP(00l) quantum islands emitting at 1.S5μm can be reduced through the optimization of SSMBE growth parameters. In optimized growth conditions, i.e. high Tc ~520°C and low P_As = 2 10^-6 torr leading to a 2D/3D growth mode transition measured by WEED at 1.8 ML, photoluminescence spectra with a FWHMs as low as 68meV at 300K have been obtained for a 4ML InSa deposit. Photoluminescence measurements as a function of the excitation power show that the multi-component PL spectra can be understood in terms of fundamental and excited levels of InAs islands. The fundamental peak (FWHM equal to 22meV at 8K) reveals a very low island size dispersion. Plane-view TEM and AFM images show that InAs islands are quantum << sticks >> aligned along [1-10], with flat top surfaces. Cross-section TEM imaging shows a very weak height dispersion attributed to the ability of the InAs/InP(00l) system to allow island height variation by monolayer fluctuation.