Optimization of the Al composition of the p-AlGaN electron blocking layer in GaInN/GaN multiquantum-shell nanowire LEDs

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 SiO${}_2$ 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. (© 2024 Wiley‐VCH GmbH)