Effective n-type doping strategy through codoping SiAl-FNin aluminum nitride

Using a first-principles pseudopotential method, we studied an effective n-type doping strategy through codoping SiAl-XN(X = F, Cl, Br, and I) in aluminum nitride. Results revealed that the donor ionization energy of the SiAl-XNcomplex is much lower than that of the corresponding isolated SiAlimpurity. Theoretically obtained ?(+/0) ionization energies are all near the conduction band minimum (CBM), which is only 1.4 meV below the CBM of the SiAl-FNpair. The low ?(+/0) ionization energy of the SiAl-XNcomplex can be explained by the combined repulsion between the X element (X = F, Cl, Br, and I)- and Si donor-induced levels.