In the n-type a little thermal exitation of the impurity (often Arsenic) introduces an electron into the conduction band, so we get electron conduction
In the n-type a little thermal exitation of the impurity (often Arsenic) introduces an electron into the conduction band, so we get electron conduction
In the p-type, an electron from the valence band is easily excited into the impurity (typically Gallium) leaving a little bubble in the filled valence band that acts like a positive electron--it is called a “hole”
notice that the conductivity goes up with temperature in a semiconductor, unlike the metal dependence, because of the increased thermal exitation with temperature