Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

1. pn junction

Explanation:
As pentavalent impurities contribute or donate electrons to the semiconductor, these are called donor impurities and similarly as these impurities contribute negative charge carriers in the semiconductor this we refer as n - type impurities. The semiconductor doped with n - type impurities is called n-type semiconductor.
Since trivalent impurities contribute excess holes to semiconductor crystal, and these holes can accept electrons, these impurities are referred as acceptor impurities. As the holes virtually carry positive charge, the said impurities are referred as positive - type or p - type impurities and the semiconductor with p type impurities is called p-type semiconductor.