The intermixing of hetero-interfaces, by Ga+ implantation and annealing, was investigated. Damage accumulation in a GaAs/AlAs superlattice was found to be less rapid than that in a GaAs/GaAlAs quantum-well structure. Low-temperature photoluminescence spectroscopy of a GaAs/AlAs superlattice was performed for doses as high as 1016/cm2. The photoluminescence spectra exhibited several emission bands on the high-energy side. The number and energy of these blue-shifted peaks were found to depend upon the implanted dose. Secondary ion mass spectrometric data suggested that they could be interpreted as being due to emission from several quantum wells, of the superlattice, which disordered at differing mixing rates. Two regimes were revealed. Thus, while the depth extension of the disordering was directly related to the post-implantation defect distribution in the high-dose regime, some diffusion of these defects during annealing occurred in the low-dose regime. Cross-sectional transmission electron microscopy confirmed that there was an effect of the structure, of the implanted sample, upon damage accumulation. A decrease in the photoluminescence intensity after annealing was attributed to the presence of extended residual defects in the implanted layers. A study of the effect of annealing time at 760C showed that the photoluminescence intensity progressively recovered, whereas the intermixing rapidly saturated.

C.Vieu, M.Schneider, R.Planel, H.Launois, B.Descouts, Y.Gao: Journal of Applied Physics, 1991, 70[3], 1433-43