Radiative recombination in silicon-on-insulator layers implanted with high dose of H+ ions

Hydrogen-terminated Si nanocrystals were performed by high-dose (5×1017cm−2) low-energy (24keV) H+ ion implantation of silicon-on-insulator (SOI) layers. The formation of the nanocrystalline phase was observed in the as-implanted samples and in those annealed at the temperature of 200–400°C. Both the Raman shift and the broadening of the phonon peak corresponded to Si nanocrystals with the diameters ranging from ∼2 to 3nm. The room-temperature photoluminescence (PL) peaked at 1.58–1.64eV and corresponded to the recombination of quantum-confined excitons in Si nanocrystals with the diameters mentioned above. The PL intensity had the bell-shaped dependence on the temperature and had its maximum near 150K. The estimated thermal activation energy of the PL was about 12.1meV and was in good accordance with the singlet–triplet splitting energy of the exciton states.