Defect reactions in low temperature electron irradiated AlAs investigated by measurements of the lattice parameter

Pseudomorphic layers of AlAs on GaAs substrates were irradiated at 4.6K with 2.5 MeV electrons up to a total dose of 2·101¹⁹ electrons/cm². X-ray diffraction was employed to investigate damage accumulation and the subsequent thermally activated annealing reactions. We observe an irradiation-induced increase of the lattice parameter which amounts to about half of the changes observed in the GaAs substrates. There is a major annealing step near room temperature, a rather continuous annealing up to 500K and a final recovery stage between 700K and 900K. The observed defect properties and defect reactions are compared to those of other III-V compounds like GaAs and InP.