New self-organized growth method for InGaAs quantum dots on GaAs(001) using droplet epitaxy

Quantum dot (QD) systems for InGaAs/GaAs without a wetting layer have been fabricated on GaAs (001) surfaces by a new self-organized growth method using droplet epitaxy with highly dense Ga droplets. Droplets of InGa alloy with highly dense Ga droplets have been formed by supplying 1) Ga, 2) In and 3) Ga molecular beams, sequentially. These highly dense Ga droplets have successfully prevented the two-dimensional growth of InGaAs during crystallization under As Bur supply. In the plan-view transmission electron microscope image, the InGaAs QDs with the density of 7 x 10(9) cm(-2) are observed. These QDs show a very sharp photoluminescence peak (full width half maximum (FWHM): 21.6 meV) at 946 nm.