@article{oai:ynu.repo.nii.ac.jp:00003938,
 author = {Mitsubori, S. and Katayama, I. and Lee, S. H. and Yao, T. and Takeda, Jun},
 issue = {6},
 journal = {Journal of physics. Condensed matter.},
 month = {Feb},
 note = {application/pdf, postprint, Dynamics of stimulated emission and ultrafast lasing in ZnO nano-multipods has been investigated with femtosecond optical Kerr shutter technique. Under band-to-band excitation with high density, stimulated emission is observed around 395-400 nm with a mode-like structure. The stimulated emission emerges with an onset time of ~2 ps and then the intensity gradually decreases with time having a blue-shift and a spectral narrowing. The characteristics of the blue-shift and spectral narrowing suggest that not only recovery of bandgap renormalization but also conversion from an electron-hole plasma (EHP) state to high density excitonic state takes place as the carrier density decreases due to recombination of electrons with holes. The mode-like structure observed strongly indicates that a high quality resonant cavity is formed between the two facets toward the leg length direction of individual nano-multipod. These results show that the ultrafast lasing observed around 395-400 nm in ZnO nano-multipods comes from population inversion in the EHP regime. We also found that the initial carrier distribution of the EHP regime in nano-multipods is much wider than that in ZnO thin films, implying that the carrier diffusion might be suppressed by their nano-size structure.},
 title = {Ultrafast lasing due to electron-hole plasma in ZnO nano-multipods},
 volume = {21},
 year = {2009}
}