Luminescence properties of GaN/GaInN nanorod light-emitting diodes fabricated by a top-down approach

This study investigates the photoluminescence (PL) behavior of nanorod (NR) light-emitting diodes (LEDs) fabricated using a top-down approach. Compared to planar LEDs, NR LEDs exhibit shorter emission wavelengths and unexpected redshifts with increasing excitation power. Self-consistent numerical simulations solving the Poisson equation were employed to examine the effects of strain relaxation on device characteristics. The results suggest that the shorter-wavelength emission of the NR LEDs originates primarily from strain relaxation, which reduces the polarization-induced electric field and mitigates the quantum-confined Stark effect. The redshift observed with increasing excitation power is more closely related to the fabrication-induced surface damage, which generates additional heat and alters the carrier relaxation dynamics under optical excitation. Additionally, potassium hydroxide treatment effectively restores the PL intensity by mitigating the plasma-induced surface defects without changing the emission wavelength. These findings provide insight into the luminescence properties of nanoscale GaN LEDs and contribute to their relevant applications.