(a) For the sputtered CdS/CdTe solar cell discussed in Problem Set 1, the highest temperature to which the cell is exposed is 400C during the 30 min CdCl, treatment. Estimate the root mean square distance that sulfur can diffuse within the bulk and along a grain boundary in the solar cell at 400C during a 30 min time period. Note that if you find values less than a ~ 0.3 nm = 3 x 10 cm, a single atomic spacing, then no diffusion has occurred. If you find values greater than d-3 m = 3 x 10+ cm, it means that the S can diffuse through the entire thickness d of the CdTe layer of the solar cell.