Temperature-Dependent Photoluminescence from GaN/Si Nanoporous Pillar Array

A GaN/Si nanoheterostructure is prepared by growing wurtzite GaN on a silicon nanoporous pillar array (Si-NPA) with a chemical vapor deposition method. The temperature evolution of the photoluminescence (PL) of GaN/Si-NPA is measured and the PL mechanism is analyzed. It is found that the PL spectrum is basically composed of two narrow ultraviolet peaks and a broad blue peak, corresponding to the near band edge emission of GaN and its phonon replicas, and the emission from Si-NPA. No GaN defect-related PL is observed in the as-prepared GaN/Si-NPA. Our experiments prove that Si-NPA might be an ideal substrate for preparing high-quality Si-based GaN nanomaterials or nanodevices.