Enhanced resonant raman scattering and electron-phonon coupling from self-assembled secondary ZnO nanoparticles.
Self-assembled secondary ZnO nanoparticles, recognized with the agglomeration of crystalline subcrystals, are successfully synthesized by a simple sol-gel method. TEM images display that one artificial cluster behaves in a single-crystal-like wurtzite structure because subcrystals coagulate as the same crystal orientation. Moreover, from the resonant Raman scattering, the as-grown sample exhibits phonon red shift; meanwhile, the coupling strength between electron and longitudinal optical phonon, determined by the ratio of second- to first-order Raman scattering cross sections, diminishes compared with the samples after postannealing at 350 and 500 degrees C. The size dependence of electron-phonon coupling is principally as a result of the Fröhlich interaction.
Cheng
Hsin-Ming
HM
Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Road., Hsinchu 30050, Taiwan, Republic of China.
Lin
Kuo-Feng
KF
Hsu
Hsu-Cheng
HC
Lin
Chih-Jen
CJ
Lin
Li-Jiaun
LJ
Hsieh
Wen-Feng
WF