Quantum dots were grown on semi-insulating GaAs by using self-assembled growth via molecular beam epitaxy, and were capped with 80nm of GaAs. The deep-level defects in samples with InAs quantum dots were investigated by using the photo-induced current transient spectroscopic technique to monitor the lateral transport of quantum dots. It was found that there were 6 deep levels, ranging from 0.127 to 0.532eV, in samples with quantum dots. Their capture cross-sections were between 1.6 x 10-15 and 7.9 x 10-15/cm2. In particular, 2 deep levels whose activation energies were 0.127 and 0.156eV below the conduction band edge were thought to be due to a defect which was related to quantum dots. These defects were thought to be related to excess As atoms or In vacancies near to the quantum dots.

Deep Level Defects of InAs Quantum Dots Grown onto GaAs by Molecular Beam Epitaxy. C.J.Park, H.B.Kim, Y.H.Lee, D.Y.Kim, T.W.Kang, C.Y.Hong, H.Y.Cho, M.D.Kim: Journal of Crystal Growth, 2001, 227-228, 1057-61