Effects of thermal processes on photoluminescence of silicon nanocrystallites prepared by pulsed laser ablation

The temperature dependence of the photoluminescence (PL) spectra of Si nanocrystallites prepared using an inert-gas-ambient pulsed laser ablation technique was characterized. Although the PL intensity of as-deposited Si nanocrystallites was very weak at room temperature, it increased with annealing in N2 or O2 gas. The PL intensity of the sample annealed in O2 gas was the largest at room temperature since the reduction in intensity with increased temperature was small. The nonradiative recombination process is discussed in terms of the temperature dependence of the PL intensity. Our results suggest that annealing of Si nanocrystallites in O2 gas reduces the nonradiative recombination of electron–hole pairs.