What are semiconductors, and how do p-type and n-type semiconductors differ? Name an application of a combination of p- and n-type semiconductors.

1. a) i) What is a semiconductor?

A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its electrical properties can be significantly altered by doping with impurities or by changes in temperature.

1. a) ii) Distinguish between a p-type semiconductor and an n-type semiconductor.

• p-type semiconductor: Created by doping a pure semiconductor with trivalent impurities (e.g., boron), resulting in a majority of holes as charge carriers.
• n-type semiconductor: Created by doping a pure semiconductor with pentavalent impurities (e.g., phosphorus), resulting in a majority of electrons as charge carriers.

**1. a) iii) Name an application of a combination of a p