Tunable Band Gap of n- type GaN Nanosheet: Effect of electric field and site of doping

Abstract

The investigation of Electronic structure of pristine Gallium nitride homobilayer(GaNS2) sheet and the effect of doping with Mn has been done using the spin polarized density functional theory. Also the effect of external applied field on electronic band structure of these pristine and doped nanosheets has been studied. It is found that doping suppressesthe energy band gap(Eg) but the extent of suppression is highly dependent on the site of doping.Eg for GaNs2 is 1.857 eV whereas for doped sites i.e g, b, c and n, energy band gaps are 0.245eV, 1.134eV, 1.169eV, and 1.305eV respectively. On applying the external electric field across the bilayer also mutates the HOMO-LUMO gap of individual nanosheets and decrease in band gap is observed on increasing the electric field. Finally, semiconductor to metal transition takes place at critical electric field (EC). EC for GaNs2is investigated to be 0.8 V/ Å and for sites g, b, c, n values of EC is found to be 1.2 V/ Å, 1.3 V/ Å, 1.4 V/ Å,1.4 V/ Å, respectively. The electric field induced changes in electronic band structurecan be utilized in electrical sensor nanodevices and site of doping can be used in engineering desirable band gap according to the requirement.