Electronic and structural properties of As-grown and alpha-particle irradiated GaAs doping superlattices

Using atomic force microscopy (AFM), low-temperature photoluminescence (bot h CW and time-resolved) as well as Raman spectroscopy, we have performed a comparative investigation of as-grown and alpha-particle irradiated GaAs do ping superlattices. From AFM no evidence of structural damages was found. O n the opposite, from optical investigations and depending strongly on the d ose of alpha-particle irradiation, the electronic properties were found to vary. At low dose, the main PL signal remained but decreased in intensity. At the same time it shifted towards low energy. At high dose, the PL answer completely disappeared. After annealing, partial recovery was found. All t ogether this indicates that, upon bombardment and annealing, first one open s and next closes new (non-radiative) defect-induced recombination paths.