Laser-induced InAs/GaAs quantum dot intermixing

Laser annealing of InAs/GaAs quantum-dot (QD) microstructures has been inve stigated for selective area tuning of their electronic shell structure. Ext ensive blueshifts of the QD excited states were observed following 20-40 s laser irradiation. In the most extreme case, we were able to shift the posi tion of the ground state transition by 298 meV, i.e., to the spectral regio n where the photoluminescence signal originates from the as-grown InAs wett ing layer. A reduction from similar to 50 to 8 meV of the full width at hal f maximum of the PL peak corresponding to this transition indicates a drast ic change in the structural characteristics of the investigated QD ensemble . The attractive feature of the laser-QD-intermixing technique is that it o ffers the possibility of obtaining targeted blueshifts and inter-sublevel e nergy spacing on the lateral scale required in the fabrication of QD-based integrated optoelectronic devices and, possibly, photonic band gap crystals . (C) 2000 American Institute of Physics. [S0003-6951(00)03745-1].