GaN-Based LEDs with hot/cold factor improved by the electron blocking layer

The authors report the study of 'thermal droop' for GaN-based light-emitting diodes (LEDs) using a single AlGaN layer with various thicknesses as the electron blocking layer (EBL). It was found that the effect of bandgap narrowing at elevated temperatures on the drop of LED output power should be negligibly smaller. It was also found that the inserted EBL could significantly reduce 'thermal droop' due to the effective suppression of electron overflow at elevated temperatures. Furthermore, it was found that we could drastically reduce the output power decrease by about 42% with a properly designed EBL.