Vacancy controlled interdiffusion of the group V sublattice in strained InGaAs/InGaAsP quantum wells

In this letter we present the results of a photoluminescence study of the interdiffusion of arsenic and phosphorous in the In0.66Ga0.33As/In0.66Ga0.33As0.7P0.3 system over the temperature range 950–600 °C. We have shown that the diffusion is Fickian with no dependence of the diffusion coefficient on the substrate doping type or etch pit density. For both tin- and sulfur-doped substrates the diffusion can be described by a diffusion coefficient D, which is given by D=D0 exp(−EA/kT), where D0=23 cm2/s and EA=3.7 eV for temperatures greater than 675 °C. This activation energy is the same as that determined for the group III interdiffusion in In0.2Ga0.8As/GaAs. Below this temperature a lower activation energy process takes over with D0=5×10−10 cm2/s and EA=1.7 eV.