Generalization of Fick's Law for Non‐Local Complex Diffusion in Semiconductors

Electron diffusion in semiconductors is studied at short distances and/or times. An extension of Fick's law with higher derivatives is introduced, and a numerical method determines how many terms are to be kept and the values of the corresponding coefficients. At high applied electric fields the asymmetric diffusion introduces an imaginary part of the Fourier‐transformed diffusion coefficient, that is, even order derivatives in the diffusion equation.