Researchers find simple fix for defects plaguing next-gen nano-LEDs
Scientists discovered that microscopic flaws in experimental red-emitting nano-LEDs stem from a manufacturing quirk—the dome-shaped templates used to grow the devices. Switching to flat starting materials could eliminate these defects entirely, potentially accelerating commercialization of nanoscale displays and lighting that could rival conventional LEDs in efficiency and cost.
Originaltitel: Cathodoluminescence investigations of dark-line defects in platelet-based InGaN nano-LED structures
<p>We have investigated the optical properties of heterostructured InGaN platelets aiming at red emission, intended for use as nano-scaled light-emitting diodes. The focus is on the presence of non-radiative emission in the form of dark line defects. We have performed the study using hyperspectral cathodoluminescence imaging. The platelets were grown on a template consisting of InGaN pyramids, flattened by chemical mechanical polishing. These templates are defect free, whereas the dark line defects are introduced in the lower barrier and tend to propagate through all the subsequent layers, as revealed by the imaging of different layers in the structure. We conclude that the dark line defects are caused by stacking mismatch boundaries introduced by multiple seeding and step bunching at the edges of the as-polished, dome shaped templates. To avoid these defects, we suggest that the starting material must be flat rather than dome shaped.</p>