Influence of carrier density on the electronic cooling channels of bilayer graphene
Influence of carrier density on the electronic cooling channels of bilayer graphene
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DOI：
10.1063/1.3633099
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发表时间：
2011-09
影响因子：
4
通讯作者：
Thomas Limmer;A. Houtepen;A. Niggebaum;R. Tautz;E. D. Como
中科院分区：
文献类型：
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作者：
Thomas Limmer;A. Houtepen;A. Niggebaum;R. Tautz;E. D. Como
我们通过飞秒瞬态吸收探测光子能量范围0.25-1.3 eV研究了单层双层石墨烯中的电子冷却动力学。从瞬态，我们提取不同的初始温度和光激发的电子和空穴的密度的载流子冷却曲线。两个制度的载体冷却，占主导地位的光学和声子发射，清楚地确定。为了增加载流子密度，两个区域之间的交叉发生在较大的载流子温度下，因为通过光学声子的冷却经历瓶颈。声学声子，这是不太敏感的饱和度，显示在高密度的贡献增加。
We study the electronic cooling dynamics in a single flake of bilayer graphene by femtosecond transient absorption probing the photon-energy range 0.25–1.3 eV. From the transients, we extract the carrier cooling curves for different initial temperatures and densities of the photoexcited electrons and holes. Two regimes of carrier cooling, dominated by optical and acoustic phonons emission, are clearly identified. For increasing carrier density, the crossover between the two regimes occurs at larger carrier temperatures, since cooling via optical phonons experiences a bottleneck. Acoustic phonons, which are less sensitive to saturation, show an increasing contribution at high density.