Question

why don't we dope a semiconductor with a hexavalent or divalent impurity???​

Answer 1

Explanation:

Germanium and silicon are group 14 elements, they have 4e in their valence shells and they form 4 bands. A large variety of solids have been prepared by combination of group 13 and15 elements and by combination of groups12 and 16 elements. Therefore we can also use hexavalent impurity.

examples : ZnS CdS, CdSe andHgTe