A Thermally Activated Exciton--Exciton Collision Process in ZnO Microrods
ZHAO Dong-Xu1, LIU Yi-Chun1,2, SHEN De-Zhen1, LU You-Ming1, ZHANG Ji-Ying1, FAN Xi-Wu1
1The Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130022
2Centre for Advanced Optoelectronic Functional Material Research, Northeast Normal University, Changchun 130024
A Thermally Activated Exciton--Exciton Collision Process in ZnO Microrods
1The Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130022
2Centre for Advanced Optoelectronic Functional Material Research, Northeast Normal University, Changchun 130024
Abstract： Room-temperature P-band emission induced by an exciton--exciton collision process was observed in ZnO micro-rods. Both temperature- and excitation-intensity-dependent photoluminescence (PL) measurements were conducted. The excitation-intensity-dependent measurement illustrated that the P-band emission could occur at far lower excitation intensity than that reported in the literature. Higher-order transitions were also observed at the excitation intensity of 7.1kW/cm2 or above. The temperature-dependent PL showed that the P-band emission process was thermally activated. It is suggested that both the density and activity of free excitons played important roles in the exciton--exciton collision process.
2004, Vol. 21 
