Insulator-to-metal phase transformation of VO2 films upon femtosecond laser excitation |
| |
Authors: | S Lysenko V Vikhnin G Zhang A Rua F Fernandez H Liu |
| |
Affiliation: | (1) Department of Physics, University of Puerto Rico, 00681 Mayaguez, Puerto Rico, U.S.A.;(2) A.F. Ioffe Physical Technical Institute, 194021 St. Petersburg, Russia |
| |
Abstract: | Light-induced insulator-to-metal phase transition of vanadium dioxide films was studied by ultrafast optical pump-probe spectroscopy.
The transient optical reflection measurement shows that both heating and laser illumination contribute to the phase transition
of VO2. Within 10−11–10−9 sec, these two mechanisms are competitive. Excited-state dynamics were found to be strongly dependent on the concentration
of structural defects and the pump laser power as well. Comparison of the transient reflection of VO2 films deposited on different substrates suggests that the excitonic-controlled light-induced insulator-to-metal phase transition
in VO2 proceeded through an intermediate state. The transient reflection measurement of VO2 in metallic phase shows a three-stage relaxation process. A polaron excitation model is introduced to describe the dynamical
process for metallic VO2. |
| |
Keywords: | Metal-insulator transition vanadium dioxide ultrafast optics transient optical properties |
本文献已被 SpringerLink 等数据库收录! |