Influence of hydrogen passivation on the luminescence of Si quantum dots embedded in Si3Nx

Silicon quantum dots (Si-QDs) of various diameters were formed by annealing of Si-rich silicon nitride (Si3Nx) films synthesized using plasma-enhanced chemical vapor deposition. To investigate the effect of annealing temperature on the luminescence of this system, samples were annealed at temperatures from 400 to 1000 degrees C. Photoluminescence (PL), x-ray absorption near edge spectroscopy, elastic recoil detection, and Fourier-transform infrared spectroscopy measurements were used for characterization. The authors found that luminescence originated from both quantum confinement effects (QCE) and defects, and that hydrogen passivation affects the PL intensity. For lower annealing temperatures, radiative recombination due to the QCE of the Si-QDs films was observed. For higher annealing temperatures (above 600 degrees C), desorption of hydrogen from the sample caused the PL intensity to decrease significantly. Si3Nx films with a lower Si content were less sensitive to this reduction in PL intensity after annealing at high temperatures (above 600 degrees C). Our results emphasize the importance of hydrogenation of the silicon nitride matrix if Si QDs are to be used in optoelectronic devices. (C) 2016 American Vacuum Society.