What will happen with the depletion region width W and the built-in voltage Vbi of a p-n junction if we increase the acceptor concentration Na of the p-type region from 1E+16 to 1E+18, while the donor concentration in the n-type region remains 1E+15 ? (1) The depletion width will increase and the built-in voltage will decrease. (2) Both the depletion width and the built-in voltage will decrease. (3) The depletion width will decrease and the built-in voltage will increase. (4) Both the depletion width and the built-in voltage will increase.

What will happen with the depletion region width W and the built-in voltage Vbi of a p-n junction if we increase the acceptor concentration Na of the p-type region from 1E+16 to 1E+18, while the donor concentration in the n-type region remains 1E+15 ? (1) The depletion width will increase and the built-in voltage will decrease. (2) Both the depletion width and the built-in voltage will decrease. (3) The depletion width will decrease and the built-in voltage will increase. (4) Both the depletion width and the built-in voltage will increase.