Ultrafast carrier and phonon dynamics in ion-irradiated graphite
Ultrafast carrier and phonon dynamics in ion-irradiated graphite
复制标题
离子辐照石墨中的超快载流子和声子动力学
DOI：
10.1063/1.1379782
复制
发表时间：
2001
影响因子：
4
通讯作者：
K. Ushida
中科院分区：
文献类型：
--
作者：
K. Ishioka;M. Hase;M. Kitajima;K. Ushida
用飞秒时间分辨反射率测量方法研究了缺陷对石墨中光激发载流子和相干声声子动力学的影响。用5keV的He+离子辐照石墨，引入了点缺陷。缺陷的引入通过空位态打开了一个衰变通道，从而增强了载流子弛豫，从而有效地与载流子-声子散射竞争。由于缺陷的额外散射，相干声子弛豫也被加速。衰减率的线性注量依赖关系可理解为单个空位对传播声子的散射。
The effect of defects on the dynamics of photoexcited carriers and coherent acoustic phonon in graphite is investigated by means of reflectivity measurements with femtosecond time resolution. Point defects are introduced by irradiating graphite with 5 keV He+ ions. Introduction of the defects enhances the carrier relaxation by opening a decay channel via vacancy states, which competes efficiently with carrier–phonon scattering. The coherent phonon relaxation is also accelerated due to an additional scattering by defects. The linear fluence dependence of the decay rate is understood as scattering of propagating acoustic phonon by single vacancies.