Light-Emitting V-Pits: An Alternative Approach toward Luminescent Indium-Rich InGaN Quantum Dots

Realization of fully solid-state white light emitting devices requires high efficiency blue, green, and red emitters. However, challenges remain in boosting the low quantum efficiency of long wavelength group-III-nitride light emitters through conventional quantum well growth. Here, we demonstrate a new direct metal-organic chemical vapor deposition approach to grow In-rich InGaN quantum dots on Si substrates using V-pits, bypassing the need for patterning or unconventional substrates. A correlative nanoscale study on the optical, compositional, and structural properties of intersecting V-pits reveals that the highly textured surface gives rise to localized high intensity red-shifted emission from the apexes of pyramids where InGaN quantum dots spontaneously form. We establish the origin of this efficient long wavelength luminescence to result from both spatially confined higher In-content deposition, as well as smaller bandgap energy basal stacking faults entrapped within a ring of low-emissivity prismatic stacking faults. Our monolithic growth approach on Si would open up new pathways toward attaining CMOS-compatible phosphor-free white light emitting solid-state devices.