Role of Gold Nanoparticles in Gallium Nitride Growth for Potential Plasmonic Device Applications

In this report, the results of gallium nitride (GaN) crystal growth on a silicon substrate covered by gold nanoparticles (AuNPs) are described using the chemical vapor deposition (CVD) technique. The formation of AuNPs by solid-state dewetting and a preferential crystallization of GaN species on the gold nucleation centers were demonstrated. The migration and embedding of gold centers during the ripening of GaN structures were evidenced by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Embedded AuNPs endowed the structural and optical properties of a semiconductor, related to the particle size, GaN crystallite, and plasmon-exciton interactions. Photoluminescence (PL) and UV-vis spectroscopy revealed a reduction in the intensity of the near band emission (NBE) at 3.4 eV in the gold-nucleated film in addition to a broadening of the absorption band edge. An increase in the density current of 0.046-0.142 mA/cm² in a gold-nucleated GaN-based p-n junction was obtained, attributed to the localized surface plasmon resonance (LSPR) effects of the embedded AuNPs. Beyond the advantages of applying group III nitrides in the electronic field, appropriate modification of the preparation method of these materials with metallic covered substrates could provide them with specific properties, according to a targeted application.