Group-V intermixing in InAs/InP quantum dots

Postgrowth intermixing in InAs/InP quantum dot (QD) structures have been investigated by rapid thermal annealing and laser irradiation techniques. In both cases, room-temperature photoluminescence (PL) measured from the QD structures after intermixing shows a substantial blueshift accompanied by an improvement in PL intensity and a reduction in linewidth. In the case of impurity free vacancy disordering, an energy shift of up to 350 meV has been achieved. The maximum differential energy shift for samples capped with SiO2 and SiNx dielectrics was found to be 90 meV. On the other hand, laser-induced intermixing allows differential energy shifts of more than 250 meV in this material system. Micro-Raman measurement shows the appearance of InAs-type and InP-type optical phonon, peaks from laser-annealed InAs/InP QDs due to the exchange of As and P at the QD interfaces. (C) 2005 American Institute of Physics.