Yellow electroluminescence realized in GaN/Si nanoheterostructures based on silicon nanoporous pillar array

GaN/Si nanoheterostructures were prepared at different growth temperatures by using chemical vapor deposition method with Si nanoporous pillar array (Si-NPA) as the substrate. We detailedly investigated the optical, structural, and electrical characteristics of the resulting GaN/Si-NPA nanoheterostructures. The photoluminescence spectra of the nanoheterostructures include three emission components, and their corresponding emission mechanisms were discussed. Further, a heterojunction device was fabricated, which showed an obvious rectifying behavior, compatible with the thermionic emission and space-charge-limited current models at low/high forward biases. More importantly, a strong yellow emission at ~ 560 nm was achieved under forward bias, which can be assigned to the defect-related transition emission in GaN. The results obtained may provide important guidelines for understanding the basic physics of GaN/Si-NPA nanoheterostructures, facilitating their potential applications in light-emitting diodes.