Effects of proton irradiation on luminescence emission and carrier dynamics of self-assembled III-V quantum dots

The effects of proton irradiation (1.5 MeV) on photoluminescence intensities and carrier dynamics were compared between III-V quantum dots and similar quantum well structures. A significant enhancement in radiation tolerance is seen with three-dimensional (3D) quantum confinement. Measurements were carried out in different quantum dot (QD) structures, varying in material (InGaAs/GaAs and InAlAs/AlGaAs), QD surface density (4/spl times/10/sup 8/ to 3/spl times/10/sup 10/ cm/sup -1/), and substrate orientation [(100) and (311) B]. Similar trends were observed for all QD samples. A slight increase in PL emission after low to intermediate proton doses is also observed in InGaAs/GaAs [100] QD structures. The latter is explained in terms of more efficient carrier transfer from the wetting layer via radiation-induced defects.