A numerical method was described for the solution of such problems in situations which involved arbitrary profiles and arbitrary functional dependences of the diffusion coefficient upon position, diffusant concentration and time. The technique was applied to various diffusion problems in semiconductor quantum wells. In particular, solutions were given for diffusion in graded interfaces, for the case of a concentration-dependent diffusion coefficient, and for the effect of a depth- and time-dependent diffusion coefficient in a superlattice; as occurred during ion implantation and the subsequent annealing out of the resultant damage. The depth dependence of the intermixing, due to ion implantation and subsequent rapid thermal annealing of a GaAs/GaAlAs multiple quantum-well structure, was deduced from the broadening of the low-temperature photoluminescence emission.

P.Harrison: Physica Status Solidi B, 1996, 197[1], 81-90