Characteristics of p-type Mg-doped GaS and GaSe nanosheets

The characteristics are investigated in the p-type Mg-doped GaS and GaSe nanosheets by means of first-principles calculations, showing that with increasing Mg doping concentration, the formation energy increases while the transition level decreases. Moreover, Mg impurity can create a shallower acceptor level in the GaSe nanosheet than in the GaS nanosheet. In particular, the transition level is 39.3 meV when Mg doping concentration is 0.056 in the GaSe nanosheets, which indicates that Mg impurity can offer effective p-type carriers in the GaSe nanosheets.