Question

GaAs is a compound semiconductor with the diamond-cubic crystal structure. The crystal structure can also be thought of as FCC with a two-atom basis, where Ga is at (0,0,0) and As is at (1/4, 1/4, 1/4). When Si is doped into GaAs, it can either substitute for Ga or for As and whether Si acts as a p-type or n-type dopant depends on which site the Si occupies. Briefly explain why Si is an n-type dopant when it substitutes for Ga but is a p-type dopant when it substitutes for As.

Answer 1