Influence of strain on built-in dipole moment in asymmetric In _xGa_1-xAs quantum dot molecules

Strain effects on a built-in electron-hole dipole moment are investigated in asymmetric In_xGa_1-xAs coupled quantum dots. We compute electron-hole separation as a function of alloy compositions for both electron and hole resonance cases. It is noted that the inclusion of strain enhances the built-in dipole moments and that the inverted electron-hole alignment is found for electron and hole resonances. Furthermore, the reversal of dipole moments gives rise to different asymmetric Stark shifts in each transition spectrum.