Impacts of <i>p</i>-AlGaN Electron Blocking Layer for the Performance of Low Current Injected Green GaN-Based Micro-LEDs

This work investigates the impacts of the p-AlGaN electron blocking layer (EBL) on the performance of low current injected green GaN-based micro-light-emitting-diodes (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>-LEDs). The peak-EQE corresponded current density of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>-LEDs with and without EBL are measured at 0.83 and 0.5 A/cm2, respectively. In addition, the related carrier transport mechanisms in these devices are analyzed by using the ABC + f(n) model. The wavelength shifts indicate that there are weakened quantum-confined stark effect (QCSE) in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>-LEDs without p-AlGaN EBL. The polarization-induced phenomena such as band-bending, hole injection, and electron confinement at the multiple q uantum wells (MQWs)/EBL or MQWs/p-GaN interface have been simulated and analyzed, and the Raman and X-ray diffraction reciprocal-space-mapping (XRD-RSM) validate the improvement of crystal quality of green InGaN/GaN MQWs by removing the p-AlGaN EBL. Moreover, the results of surface temperature distribution indicated that the thermal performance of low-current injected green <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>-LEDs could also be improved by removing the p-AlGaN EBL.