Planar density of Si

exercise 3_4940

Silicon (Si) has a diamond crystal structure which has a lattice spacing of a = 0.542 nm.

(a) Calculate the density of Si atoms per cm 2 on {100} planes.

(b) Treat atoms as rigid spheres with radii equal to one-half of the distance between nearest neighbors. Calculate the percentage of volume occupied by the Si atoms, i.e., its packing fraction.