Carriers

In a crystal of semiconductor material thermal agitation will cause a number of electrons to dissociate from their parent atoms; in moving about the crystal they act as carriers of negative charge. Other electrons will move from neighboring atoms to fill the space left behind, thus causing the holes where no electrons exist in the lattice to be transferred from one atom to another. As these holes move around they can be considered as carriers of positive charge. See impurity. Seebarge carriers, top carriers