First principles study of the electronic and optical properties of GaAs nanoparticles under the influence of external uniform electric field

► HOMO-LUMO gap of the nanoparticles is significantly more than GaAs bulk band gap. ► HOMO-LUMO gap of the nanoparticles decreases with increase of the nanoparticles size. ► External electric filed decrease the HOMO-LUMO gap of the nanoparticles. ► Dipole moment of nanoparticles increases with gain of the electric field strength. ► Absorption peaks of GaAs nanoparticles shows red shift with applying electric field.