On quantifying the group-V to group-III interdiffusion rates in InxGa1-xAs/InP quantum wells

The interdiffusion rate of group-V and group-III sublattice atoms in InxGa1-xAs/InP quantum well structures induced by proton implantation has been investigated using differential reflectance (DR), photoluminescence (PL) and theoretical modelling. Based on DR, PL and modelling results, we found the unique value of k (L-V/L-III) ratio for three different InGaAs quantum well structures, namely lattice matched (LM), tensile strained (TS) and compressively strained (CS). The k ratio of TS, LM and CS was 1.05, 1.25 and 1.40 respectively. These ratios were slightly higher than unity indicating that the diffusion coefficient of the group-V sublattice was larger than that of the diffusion coefficient of the group-III sublattice. Change in the interdiffusion rate of group V and group III in the lattice-matched and strained (TS, CS) quantum well structures was most likely due to the different strain profile developed in the quantum well region as a result of changing the quantum well composition.