Investigations of interdiffusion in InGaAsP multiple-quantum-well structures by photoreflectance

We present the investigations of interdiffusion in InGaAsP multiple-quantum-well (MQW) structures using photoreflectance (PR) and photoluminescence (PL) measurements. It is found that the degree of compositional intermixing induced by the processes of ion implantation and rapid thermal annealing in MQW structures can be obtained through the energy shift of the 11H excitonic transition. Besides, the strain relaxation resulting from intermixing is studied through the high order excitonic transitions observed in PR spectra. It is found that the splitting energy between the 11H and 11L transitions decreases as a result of increasing the degree of intermixing. Based on the theoretical calculation considering the strain effect and the different diffusion ratios between the group-III and group-V atoms, the data analysis have been done. It is pointed out that the diffusion coefficients and the ratio of diffusion rates between the group-V and group-III atoms has been enhanced by the P+ ion implantation. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)