I've been trying to predict the theoretical annealing condition of a pure Ge thin film sputtered on Si substrate, the idea behind this process is to create a smooth composition gradient through the thin film while maintaining low threading dislocation density.
The interdiffusivity I found could be state as:
D(xGe)=310exp(-4.66eV/kT)exp(8.1×xGe)
With D being a function of concentration, no regular Fick's law solution could be put into use, I'd like to know that whether Fick's second law is solvable when I put the diffusivity above in the equation. Thank you.