Time-resolved study of stimulated emission in ZnO tetrapod nanowires

摘要

ZnO tetrapod nanowires were fabricated by evaporation of Zn in a N_2 gas flow. Stimulated emission with a threshold of approx 100 mu J cm~(-2) was observed and the linewidths of individual modes were in the range 0.7-0.9 nm. Time-resolved measurements have been performed at different excitation powers. With an increase of the pump power, the transition from exciton stimulated emission to the electron-hole plasma regime can be clearly observed. Both electron-hole plasma and exciton emission have decay times under 10 ps.