New Photoluminescence Transition in GaAs InvolvingD−States

Abstract

Low temperature photoluminescence results from high purity epitaxial GaAs are presented, and a new type of transition involving negatively charged donor ions and neutral acceptors is identified. At low temperatures and excitation densities this becomes the dominant radiative process, with a linewidth of only $\ensuremath{\sim}1{\mathrm{cm}}^{\ensuremath{-}1}$. The temperature dependence of this new transition reveals a binding energy of $2.65\ifmmode\pm\else\textpm\fi{}0.35\mathrm{cm}{}^{\ensuremath{-}1}$, consistent with the spectroscopic value of $2.8\ifmmode\pm\else\textpm\fi{}0.2{\mathrm{cm}}^{\ensuremath{-}1}$ and with theoretical predictions. This is to our knowledge the first experimental determination of the ${D}^{\ensuremath{-}}$ binding energy in unperturbed GaAs.