Question

Why is p type semiconductor and n type semiconductor made on same element in pn junction?

Answer 1

p-n junction diodes are made up of two adjacent pieces of p-type and n-type semiconducting materials. p-type and n-type materials are simply semiconductors, such as silicon (Si) or germanium (Ge), with atomic impurities; the type of impurity present determines the type of the semiconductor. The process of purposefully adding impurities to materials is called doping; semiconductors with impurities are referred to as "doped semiconductors"