High efficiency InGaN nanowire tunnel junction green micro-LEDs

Abstract

We report on the study of InGaN nanowire green light emitting diodes (LEDs) with lateral dimensions varying from ∼1 to 10 μm. For a device with an areal size ∼3 × 3 μm2, a maximum external quantum efficiency ∼5.5% was directly measured on wafer without any packaging. The efficiency peaks at ∼3.4 A/cm2 and exhibits ∼30% drop at an injection current density ∼28 A/cm2. Detailed analysis further suggests that a maximum external quantum efficiency in the range of 30%-90% can potentially be achieved for InGaN nanowire micro-LEDs by optimizing the light extraction efficiency, reducing point defect formation, and controlling electron overflow. This study offers a viable path for achieving ultrahigh efficiency micro-LEDs operating in the visible.