Preparation of GaN Nanocrystals with Single Ag Cores

We report on a low-temperature hybrid method for the preparation of GaN nanocrystals (NCs) with embedded single Ag cores. GaN growth is realized by a physical vapor deposition of Ga atoms on a SiO₂ substrate with colloidal Ag nanoparticles on its surface, assisted with an ultralow energy (50 eV) nitrogen-ion-beam bombardment at temperatures being significantly lower (T < 350 °C) than in conventional GaN deposition techniques (e.g., MOCVD, 1000°C). We call this method Low Temperature Droplet Epitaxy (LTDE). The low deposition temperature allows GaN nanocrystals to be prepared with embedded metal–aluminum colloidal nanoparticles as their cores. A combination of STEM, SEM, scanning Auger microscopy, XPS, and AFM was applied to characterize semiconductor and metal nanoparticles. By their implementation, we optimized morphology, structure, and chemical composition of these nanocrystals and, consequently, demonstrated their enhanced photoluminescent properties.