Research on Electrical Efficiency Degradation Influenced by Current Crowding in Vertical Blue InGaN-on-SiC Light-Emitting Diodes

Current-induced electrical efficiency degradation (EED) is identified as a strong power conversion efficiency-limiting factor for vertical blue InGaN-on-SiC light-emitting diodes (LEDs). It is found that EED is caused by an increase in series resistance that follows current crowding. EED starts at the moderate-current domain ( ≥ 10
^-3
A) and limits the power conversion efficiency at the level of ≤ 75% in the high-current domain (>;1.0 A). By decreasing current spreading length, EED also causes the optical efficiency to degrade and stands for an important aspect of the vertical LED's performance.