Investigating the Effect of Piezoelectric Polarization on GaN-Based LEDs with Different Prestrain Layer by Temperature-Dependent Electroluminescence

Abstract

The effect of piezoelectric polarization on GaN-based light emitting diodes (LEDs) with different kinds of prestrain layers between the multiple quantum wells (MQWs) and n-GaN layer is studied and demonstrated. Compared with the conventional LED, more than 10% enhancement in the output power of the LED with prestrain layer can be attributed to the reduction of polarization field within MQWs region. In this study, we reported a simple method to provide useful comparison of polarization fields within active region in GaN-based LEDs by using temperature-dependent electroluminescence (EL) measurement. The results pointed out that the polarization field of conventional LED was stronger than that of the others due to larger variation of the wavelength transition position (i.e., blue-shift change to red-shift) from 300 to 350 K, and thus the larger polarization field must be effectively screened by injecting more carriers into the MQWs region.