1. Semi-conducting materials

In electronics, materials are classified according to their current carrying capacity. They are conductors, insulators and semi-conductors.

• Conductors have free electrons; therefore have excellent current carrying capacity. Example: Copper
• Insulators have tightly bonded electrons and will not conduct electricity. Example: Rubber
• Semiconductors allow partial or semi conduction of the current. Its current carrying capacity is between an insulator and a conductor. Most commonly used semiconductor materials are crystalline inorganic solids such as Silicon and Germanium. Semiconducting material are used for manufacturing diodes and transistors.

      1.1 Atomic structure of silicon; it has 4 valence electrons

             1.2 Atomic structure of Germanium; it has four valence electrons