Recombination by Tunneling in Electroluminescent Diodes

Abstract

The theory of photon-assisted tunneling in the presence of an electric field is developed and used to obtain quantitative expressions for the line shape and intensity of light emitted by forward-biased electroluminescent diodes in the "peak-shift" region. Recombination of tunneling electrons and holes through one or more intermediate states is also considered and shown to produce an "excess" current which varies as the nth root of the "peak shift" intensity, where $n\ensuremath{\approx}2$ for processes involving one intermediate state and $n>2$ for more than one. Auger recombination through these same states is shown to provide an explanation for the high-energy emission ($h\ensuremath{\nu}\ensuremath{-}\mathrm{eV}\ensuremath{\gg}\mathrm{kT}$), which varies as the square of the current and is frequently observed at low currents in electroluminescent diodes.