Role of the electron blocking layer in the low-temperature collapse of electroluminescence in nitride light-emitting diodes

The low-temperature breakdown of the electroluminescence intensity (ELI) of blue/violet InGaN-based light-emitting diodes (LEDs) is shown to be independent of the structural details of the LED active region. Instead, the presence of an electron blocking layer (EBL) plays a decisive role. The authors attribute the ELI collapse to the low-temperature hole-blocking properties of the EBL. However, removing the EBL leads to a much reduced ELI because of a disproportional increase of electron overflow processes, which shows that the presence of an EBL in blue/violet InGaN-based LEDs is still essential. Optimization of the EBL by means of Mg doping is discussed.