Explain Intrinsic Semiconductor.
Intrinsic Semiconductor: An extremely pure semiconductor is termed as intrinsic semiconductor. But at absolute zero temperature its valence band is totally filled and the conduction band is fully empty. While the temperature is raised several electrons are lifted to conduction band leaving behind holes into valence band. While an electric potential difference is applied across a pure semiconductor remained at room temperature, the current conduction get place by two types of charge carriers, namely holes and electrons. Thus the total current inside the semiconductor is the sum of currents due to free electrons and holes.