EVERYDAY SCIENCE

Detailed explanation-1: -In the case of semiconductors, as temperature increases, electrons in the valence band acquire sufficient energy to be promoted across the “energy gap” into the conduction band. When this occurs, these promoted electrons can move and conduct electricity.

Detailed explanation-2: -At room temperature, a semiconductor has enough free electrons to allow it to conduct current. At or close to absolute zero a semiconductor behaves like an insulator. When an electron gains enough energy to participate in conduction (is “free"), it is at a high energy state.

Detailed explanation-3: -The electrical conductivity of a semiconductor depends on a variety of conditions, including applied voltage or current, or the intensity of the infrared radiation, ultraviolet radiation, or visible light on the surface. This is why semiconductors are used to make photovoltaic systems.

Detailed explanation-4: -Semiconductors containing almost no impurities conduct almost no electricity. But when some elements are added to the semiconductors, electricity passes through them easily. Semiconductors comprising a single element are called elemental semiconductors, including the famous semiconductor material Silicon.

Detailed explanation-5: -A substance that will conduct electricity only under certain conditions is called a semiconductor. Many semiconductors contain the metalloid silicon. Metalloid elements have properties of metals and of nonmetals.