A facility at PNCCAT in the Advanced Photon Source measures with subnanosecond time resolution both XAFS and diffraction on femtosecond laserexcited samples. XAFS measures with relatively high efficiency the time for the laser excitation to couple to the lattice, the sample temperature after reaching thermal equilibrium, any ablation of the sample with time, and, in many cases can distinguish between the amorphous and crystalline states. Preliminary measurements on 200nm thick polycrystal Ge films indicate that the time for transferring the laser excitation to thermal heating of the lattice is less than 2nanoseconds when the initial temperature is 560K.
Revised: November 15, 2005 |
Published: November 1, 2005
Citation
Stern E., D. Brewe, K.M. Beck, S.M. Heald, and Y. Feng. 2005.SubNanosecondTime Resolved XAFS of Laser Excited Thin Ge Films.Physica Scripta T115.PNNL-SA-47229.