The impact of group-III vacancy diffusion, generated during dielectric cap induced intermixing, on the energy state transition and the inhomogeneity reduction in the InGaAs/GaAs quantum-dot structure was investigated. A 3-dimensional quantum-dot diffusion model and photoluminescence data was used to determine the thermal and the interdiffusion properties of the quantum dot. The band gap energy variation related to the dot uniformity was found to be dominantly affected by the height fluctuation. A group-III vacancies migration energy Hm for InGaAs quantum dots of 1.7eV was deduced. This result was similar to the value obtained from the bulk and GaAs/AlGaAs quantum-well materials confirming the role of SiO2 capping enhanced group-III vacancy induced interdiffusion in the InGaAs quantum dots.

Group-III Vacancy Induced InxGa1-xAs Quantum Dot Interdiffusion. H.S.Djie, O.Gunawan, D.N.Wang, B.S.Ooi, J.C.M.Hwang: Physical Review B, 2006, 73[15], 155324 (6pp)