Stress relaxed nanoepitaxy GaN for growth of phosphor‐free indium‐rich nanostructures incorporated in apple‐white LEDs

Abstract

AbstractPhosphor‐free apple‐white light emitting diodes (LEDs) have been fabricated using dual stacked InGaN/GaN multiple quantum wells (MQWs) comprising a lower set of long wavelength emitting indium rich nanostructures incorporated in MQWs with an upper set of cyan‐green emitting MQWs. The LEDs were grown on nano‐epitaxial lateral overgrown (ELO) GaN template formed by regrowth of GaN over SiO2 film patterned using an anodic alumina oxide mask with holes of ∼125 nm diameter and a period of 250 nm. The MQWs grown on the nano‐ELO GaN templates show stronger photoluminescence intensity and a higher activation energy for their peak emission. A minimal shift in the electroluminescence (EL) spectra with higher injection current applied for LEDs grown on ELO‐GaN compared to conventional GaN template, suggests a reduction in strain of the quantum well layers on the nano‐ELO GaN template. An enhancement in the light extraction efficiency is also achieved with multiple scattering via the embedded SiO2 mask.