Coherent Diffusion in InGaAsP Heterostructures

摘要

Initially lattice-matched coherent heterostructures comprising regularly-spaced 5 nm InGaAs quantum wells separated by 5 mn InP spacers were grown on <001> InP monocrystalline substrates by molecular beam epitaxy. The homogenization behaviour of these structures at 710 ℃ was studied by X-ray diffraction and quantitative transmission electron microscopy. The couples remained coherent through the homogenization process, and became elastically strained as a result of partial homogenization. The response of the system to doping was also observed. The thermodynamic properties of the quaternary system were modeled, and the Hessian of the coherent free energy functional was combined with the observed diffusion response to estimate the elements of an atomic mobility matrix for this system.