Low-temperature photoluminescence of hydrogen Ion and plasma implanted silicon and porous silicon

Low-temperature photoluminescence in the infrared region of hydrogen implanted single crystalline silicon is investigated. Both beam-line ion implantation and plasma immersion ion implantation (PIII) are used. The beam-line implanted samples show a broad photoluminescence band below the band gap, whereas the PIII implanted samples show at least one more peak at 1.17 eV and a much wider photoluminescence band. The origins are investigated and the peak at 1.17 eV appears to originate from nonphonon emission enhanced by lattice disorder. Our results suggest that PIII may be a better technique than beam-line ion implantation in introducing a certain disorder into the silicon lattice to circumvent the conservation of quasimomentum and consequently enhance the light emission efficiency from the modified Si samples. Our conclusion is further supported by results from plasma implanted porous Si.