Structural and optical properties of stacked self-assembled InAs/InGaAs quantum dots on graded Si1-xGex/Si substrate

We have investigated the effects of InAs monolayer coverage on the structural and optical characteristics of stacked InAs quantum dot (QD) layers on graded Si-1 (-) Ge-x(x)/Si substrate. No preferential InAs QDs nucleation was observed along the cross-hatched lines on the graded Si-1 (-) Ge-x(x)/Si substrate. Employing alternate-beam molecular beam epitaxy, InAs QDs with areal density as high as 7x10(10) cm(-2) was achieved. Temperature dependence of the InAs QDs optical properties is discussed. The InAs QDs show room-temperature photoluminescence at 1.3 mu m with full width at half-maximum of 65 nm. The results are significant for potential realization of III-V QD devices on silicon-based platforms. (c) 2008 American Institute of Physics.