Surface Hydride Composition of Plasma-Synthesized Si Nanoparticles

We have determined the surface hydride composition of amorphous and crystalline Si nanoparticles (NPs) (3-5 nm) synthesized in a low-temperature SiH(4)/Ar plasma using in situ attenuated total reflection Fourier-transform infrared spectroscopy and H(2) thermal effusion measurements. With increasing power to the plasma source, the particles transition from amorphous to crystalline with a corresponding increase in the fraction of SiH species on the surface. The surface hydride composition indicates that Si NPs synthesized at higher plasma powers crystallin in the gas-phase due to a greater degree of plasma-induced heating, which enhances the desorption rates for SiH(2) and SiH(3). Furthermore, these Si NPs do not contain any detectable H in the bulk.