Negatively charged excitons in coupled double quantum wells

We study magneto-optical spectra of neutral and negatively charged excitons (${\mathrm{X}}^{\mathrm{-}}$) in remotely doped double quantum wells with coupled conduction bands. We observe photoluminescence due to the recombination of ${\mathrm{X}}^{\mathrm{-}}$ leaving an excess electron in the adjacent quantum well (QW), which anticrosses the single-QW ${\mathrm{X}}^{\mathrm{-}}$ line with applied gate bias. We see also the inter-QW ${\mathrm{X}}^{\mathrm{-}}$ comprising an electron in either well.