Large energy shifts in GaAs-AlGaAs quantum wells by proton irradiation-induced intermixing

Abstract

Proton irradiation and subsequent rapid-thermal annealing are used to create intermixing in GaAs-Al0.54Ga0.46As quantum wells of various thicknesses. Very large energy shifts (up to 200 meV) with no apparent saturation have been observed even up to a dose of about 4×1016 cm−2. This effect is explained in terms of the dilute irradiation damage and the evolution of discrete (point) defects during annealing. In comparison to heavy ion irradiation effects, high point defect fraction in the case of light ions leads to efficient intermixing with large energy shifts. Although much of the proton energy loss occurs across the quantum wells, the generated defect density is dilute, and hence good recovery in photoluminescence intensities is achieved after rapid thermal annealing.