Efficient carrier multiplication in InP nanoparticles

Efficient carrier multiplication in InP nanoparticles is reported; ultrafast transient absorption measurements at the band edge were used to determine the number of excitons per photoexcited nanoparticle for a range of both excitation fluences and photon energies. At photon energies greater than 2.1±0.2 times the band gap, an average of more than 1 exciton per photoexcited nanoparticle was found even in the limit of vanishing fluence. The average number of excitons generated by an absorbed photon was measured to be 1.18±0.03 for excitation photons with energies 2.6 times the band gap. © 2010 The American Physical Society.