Systematic Analysis of the Photocurrent Spectroscopy on InGaN/GaN Blue Light-Emitting Diodes

We demonstrate a method of systematic analysis for the photocurrent spectroscopy on InGaN/GaN light-emitting diodes (LEDs). By normalizing photocurrent data at a photon energy of 3.2 eV for blue LEDs, we show that accurate comparison of active quantum wells is possible. Bias-dependent photocurrent measurements reveal that there are fixed points in photocurrent data from which an effective bandgap energy can be determined. The method presented in this paper can be useful when one needs to compare the LEDs fabricated at different times or by different processes.