Kinetics ofH2passivation of Si nanocrystals inSiO2

Time-resolved photoluminescence measurements were used to study the passivation kinetics of luminescence-quenching defects, associated with Si nanocrystals in ${\mathrm{SiO}}_2,$ during isothermal and isochronal annealing in molecular hydrogen. The passivation of these defects was modeled using the generalized simple thermal model of simultaneous passivation and dissociation, proposed by Stesmans. Values for the reaction-rate parameters were determined and found to be in excellent agreement with values previously determined for paramagnetic Si dangling-bond defects ${(P}_b$-type centers) found at planar ${\mathrm{S}\mathrm{i}/\mathrm{S}\mathrm{i}\mathrm{O}}_2$ interfaces; supporting the view that nonradiative recombination in Si nanocrystals is dominated by such defects.