He+-ion irradiation effect on intersubband transitions in GaAs/AlGaAs multiple quantum wells

Intersubband transitions in 3 MeV He+-ion irradiated GaAs-AlGaAs multiple q uantum wells were studied using an optical absorption technique. The inters ubband transitions were completely depleted in samples irradiated with dose s as low as 1x10(14) cm(-2). Thermal annealing recovery of intersubband tra nsitions was observed in samples irradiated with lower doses. On the other hand, intersubband transitions in heavily irradiated (doses > 3x10(14) cm(- 2)) samples do not show thermal annealing recovery, which indicates that ir radiation-induced defects are so severe that thermal annealing does not rep air the damage. The total integrated areas of the intersubband transitions in irradiated samples and in a control sample were monitored as a function of annealing temperature. (C) 2001 American Institute of Physics.