Impact of V-defects on current flow and recombination pathways in long-wavelength GaN-based light-emitting diodes

Abstract

In long-wavelength GaN-based light-emitting diodes (LEDs), {101¯1} V-defect sidewalls provide a current pathway for lateral electron and hole injection into the (0001) quantum wells (QWs). However, experimental techniques often struggle to distinguish the specific nature of this injection, particularly in determining whether the lateral current flow is governed by drift or diffusion. Moreover, the impact of Shockley–Read–Hall (SRH) recombination within V-defect sidewall (QWs) is largely unexplored. In this work, a two-dimensional self-consistent Poisson and drift–diffusion solver, integrated with localization landscape theory and random alloy disorder in the InGaN QWs to account for carrier transport and quantum effects, is used to study the carrier transport and recombination in and around V-defects. The results demonstrate that the current flows into the planar (0001) QWs from the V-defect rims (the interface region between c-planes and V-defect sidewalls) largely through diffusive transport, indicating that the injection pathways for both electrons and holes are direct and rapid. Compared to the radiative recombination rate in c-plane QWs, the SRH recombination rate within V-defect sidewall QWs is relatively low. This suggests that SRH recombination in V-defect sidewall QWs is a minor factor in long-wavelength GaN-based LEDs. Overall, this study offers mechanistic insights into current flow, revealing how it governs the carrier transport and recombination in V-defect sidewall QWs.