The differential efficiency of GaInP quantum well lasers

Using experimental measurements of spontaneous emission spectra, we have separated the effects that current spreading and Fermi-level pinning have on the temperature dependence of the external differential efficiency of GaInP laser diodes. We conclude that a major factor contributing to the decrease of external differential efficiency with increasing temperature is a decrease in injection efficiency due to incomplete Fermi level pinning at threshold in the barrier regions alongside the well, and an increase in barrier recombination as the temperature increases.