Visible-light emission at room temperature in Mn-doped Si light-emitting diodes

Abstract

We demonstrate Si-based light-emitting diodes that continuously emit reddish-yellow visible light at room temperature by utilizing optical transitions between the p-d hybrid orbitals of Mn atoms doped in Si. Our light-emitting diodes show clear visible-light electroluminescence with two peaks at ${E}_{1}=1.75$ and ${E}_{2}=2.30\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$, corresponding to optical transitions between p-d hybrid orbitals of Mn atoms. The electrons at the p-d hybrid orbitals of Mn in Si are excited by hot holes that are accelerated by an intensive electric field in the depletion layer of reverse biased Si $p\text{\ensuremath{-}}n$ junctions containing a Mn-doped Si (Si:Mn) layer. The observed two peaks at ${E}_{1}=1.75$ and ${E}_{2}=2.30\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$ are redshifted and blueshifted by 0.14 eV, respectively, from those of GaAs:Mn or ZnS:Mn. Our observations are consistent with the $p\text{\ensuremath{-}}d$ hybridized electronic structure of Mn atoms doped in Si as predicted by first-principles calculations.