Depth profiling of defect distribution in an AlGaAs/GaAs multiple quantum well structure induced by low-energy ion beam etching

Dry etching induced damage in Alo.35Gao.65As/GaAs multiple quantum well (MQW) structures has been investigated by high depth resolution (+ 1 nm) confocal photoluminescence (PL) measurements on bevelled surface sections of MQW structures shaped by argon and nitrogen ion beam etching (IBE). The IBE induced defect profile is explained with a model including the permanent etching of the surface and the defect diffusion during the etch process. The high values of the defect diffusion coefficients are attributed to radiation enhanced defect diffusion. The reasons for the low defect concentration induced by the nitrogen IBE process compared to argon IBE process and the nature of the damage are discussed.