2. A pn junction diode has the doping profile sketched in the figure below. Make the assumption that Xn>xo for all applied biases of interest (Xn follows the same definition as

in the lecture). (a) What is the built-in voltage across the junction? Justify your answer. (b) Invoking the depletion approximation, sketch the charge density p versus x inside the diode. (c) Obtain an analytical solution for the electric field, E(x), inside the depletion region. ND-NA Not N₂2 Xo -NA