Investigation of the device degradation for commercial light-emitting Diodes (LEDs) using spatially and time-resolved electro- and photoluminescence

Commercial LEDs with different colors (ex. InGaN and AlInGaP) were studied using spatially and time resolved Electroluminescence (EL) and Photoluminescence (PL) measurements. A novel experimental setup was used enabling performance of all these techniques at the same point with high temporal resolution, speed and accuracy. LEDs under the study demonstrated inhomogeneous broadening of the luminescence peak. PL and EL spectra observed for these LEDs were different as a result of different radiative transitions attributed to each phenomenon. Time-resolved data for fixed wavelengths demonstrated multiple time spectra at different photon emission energies due to inhomogeneous distribution of Gallium and Indium for InGaN or Gallium and aluminum for AlGaInN.