4.13 The drift velocities of holes in a silicon sample are vdr = 0.02 μm/ps, var = 0.04 μm/ps, and var = 0.07 μm/ps at E = 0.5 V/μm, E = 1.0 V/μm, and E5 V/μm, respectively. Determine the corresponding diffusion coefficients and comment on the results. The temperature is T = 300 K.