Hot phonon decay in supported and suspended exfoliated graphene
Hot phonon decay in supported and suspended exfoliated graphene
复制标题
DOI：
10.1103/physrevb.83.121404
复制
发表时间：
2011-03-14
影响因子：
3.7
通讯作者：
Hendry, E.
中科院分区：
文献类型：
--
作者：
Hale, P. J.;Hornett, S. M.;Hendry, E.
近红外泵浦-探测光谱已被用来测量单层和多层石墨烯中光激发载流子的超快动力学。我们观察到两个衰变过程发生在100 fs和2 ps的时间尺度。第一个是由于系统中的快速电子-声子热化。第二个时间尺度被发现是由于热声子的缓慢衰减。使用一个简单的理论模型，我们计算热声子衰减率，并表明它是显着更快的单层薄片比多层的。我们观察到这种增强的衰减率在支持和悬浮片，从而证明它有一个内在的起源。可能的衰减机制，如弯曲声子，可能会导致这种增强进行了讨论。
Near infrared pump-probe spectroscopy has been used to measure the ultrafast dynamics of photoexcited charge carriers in monolayer and multilayer graphene. We observe two decay processes occurring on 100-fs and 2-ps time scales. The first is attributed to the rapid electron-phonon thermalization in the system. The second time scale is found to be due to the slow decay of hot phonons. Using a simple theoretical model we calculate the hot phonon decay rate and show that it is significantly faster in monolayer flakes than in multilayer ones. We observe this enhanced decay rate in both supported and suspended flakes and thereby demonstrate that it has an intrinsic origin. Possible decay mechanisms, such as flexural phonons, that could cause such an enhancement are discussed.