Why is Indium called an acceptor impurity?

Most electronic devices are based on creating semiconductors out of nearly perfect silicon crystals that have been doped with inpurities. Silicon has 4 valence electrons and forms a lattice where each atom is bonded to four adjacent atoms. This ... read more

The number of impurity atoms is generally in the one per billion to one per thousands range. An acceptor impurity like indium or boron has only three valence electrons. This leaves a"hole" or a localized positive charge that attracts surrounding valence electrons. read more

In semiconductor physics, an acceptor is a dopant atom that when added to a semiconductor can form a p-type region. Boron atom acting as an acceptor in the simplified 2D Silicon lattice. For example, when silicon (Si), having four valence electrons, needs to be doped as a p-type semiconductor, elements from group III like boron (B) or aluminium (Al), having three valence electrons, can be used. read more