Optimization of the Al Composition of the p‐AlGaN Electron Blocking Layer in GaInN/GaN Multiquantum‐Shell Nanowire LEDs

Abstract

The aim is to develop highly efficient GaInN/GaN nanowire (NW)‐based light‐emitting diodes (LEDs), which are composed of GaN NWs and multiquantum shell (MQS) active regions. These regions incorporate the polar c‐plane, nonpolar r‐plane, and semipolar m‐plane. A challenge with MQS‐LEDs is that the current path through the c‐plane MQS tends to dominate under low‐current injection conditions. Given that the MQS on the c‐plane is very defective, this injection current is mainly subjected to nonradiative recombination. Therefore, this study explores various optimizations of the p‐AlGaN electron blocking layers (EBLs) to minimize the current injection into the MQS in the c‐plane region. The samples are subsequently grown using a specific process. This involves n‐GaN NWs, GaInN/GaN‐based quantum shells, p‐AlGaN EBLs with different Al compositions, and p‐GaN shells. All these are developed by metal–organic vapor phase epitaxy on an n‐GaN template featuring a SiO2 hole pattern. NW LEDs are fabricated and subsequently their device characteristics are investigated. Under low‐current injection, the sample with a lower Al composition exhibits higher luminescence intensity. However, this trend reverses when the injection current increases. The findings suggest that AI composition and thickness in the p‐AlGaN EBL significantly affect the output power and the emission wavelength.