Calculate the built-in voltage of a junction in which the p and n regions are doped equally with 5 × 10^16 atoms/cm^3. Assume n i =1.5 × 10^10/cm^3. With the terminals left open, what is the width of the depletion region, and how far does it extend into the p and n regions? If the cross-sectional area of the junction is 20 μm^2,find the magnitude of the charge stored on either side of the junction.