Determination of junction temperature in AlGaInP∕GaAs light emitting diodes by self-excited photoluminescence signal

Abstract
The photoluminescence(PL) of the GaAs substrate excited by the electroluminescence of the active layer is adopted to determine the junction temperature in Al Ga In P ∕ Ga As light emitting diodes. Based on the Varshni equation for GaAs, the temperaturemeasured by this approach is consistent with that obtained by the emission peak energy shift approach. As the PL signal is generated within the substrate, no calibration dependent on the device structure is necessary to determine the junction temperature of the device.