Semi-conductors are made by adding impurities to silicon wafers. The silicon wafer is 0.1 cm thick and originally contains one phosphorus (P) atom for every 10 million Si atoms. After the diffusion process, there are 379 phosphorus atoms for every 10 million Si atoms at the top surface and the concentration at the bottom surface did not change. Calculate the concentration gradient in atomic percent/cm Note: The lattice constant of diamond cubic silicon is 5.4307 angstroms with 8 atoms per cell. The answer should have 3 decimals of accuracy.