Layer disordering of strained-layer superlattices, caused by low-damage N+ or Li+ ion implantation and low-temperature annealing, was demonstrated. Interdiffusion of Se and S atoms was observed by means of secondary ion mass spectrometry. By using reflectance measurements, a significant decrease in the refractive index was detected in the disordered strained-layer superlattices. In the photoluminescence spectra, strong excitonic emission was observed at around 400nm in the disordered strained-layer superlattice. This corresponded to damage recovery. A slight red-shift of the photoluminescence peak, which was observed in the early stages of annealing, was attributed to a relaxation of the misfit strain via interdiffusion. At longer annealing times, the photoluminescence peak of implanted strained-layer superlattice samples shifted towards the higher-energy side. This clearly indicated the occurrence of layer disordering in the superlattice.

T.Yokogawa, T.Saitoh, T.Narusawa: Applied Physics Letters, 1991, 58[1], 53-5