Detecting the major charge-carrier scattering mechanism in graphene antidot lattices
Detecting the major charge-carrier scattering mechanism in graphene antidot lattices
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DOI：
10.1016/j.carbon.2018.12.080
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发表时间：
2019-04-01
期刊：
影响因子：
10.9
通讯作者：
Hao，Qing
中科院分区：
文献类型：
--
作者：
Xu，Dongchao;Tang，Shuang;Hao，Qing
载流子散射对石墨烯、黑磷烯和碲等二维材料的电学特性至关重要。除了原始的二维材料之外，还可以通过纳米孔模式（如纳米或原子尺度的孔（反点））在材料上实现进一步的定制特性。例如，近年来研究了石墨烯反点阵（GALs）的结构依赖的电学/光学性质。然而，详细的载流子散射机理尚不完全清楚。本文通过分析栅极电压调谐后的最大塞贝克系数和费米能级位移，揭示了电荷载流子散射的能量敏感性和主要散射机制。结果表明，孔边捕获电荷的散射占主导地位。对于热电效应，方形图案的栅极电压相关功率因数在400 K时可高达554 μW/cm⋅K 2。凭借其高导热系数和功率因数，这些gal可以很好地适用于电子设备中的“主动冷却器”，其中热点产生的热量可以通过被动热传导和主动珀尔帖冷却来去除。
Charge carrier scattering is critical to the electrical properties of two-dimensional materials such as graphene, black phosphorene, and tellurene. Beyond pristine two-dimensional materials, further tailored properties can be achieved by nanoporous patterns such as nano-or atomic-scale pores (antidots) across the material. As one example, structure-dependent electrical/optical properties for graphene antidot lattices (GALs) have been studied in recent years. However, detailed charge carrier scattering mechanism is still not fully understood. In this paper, the energy sensitivity of charge-carrier scattering and thus the dominant scattering mechanisms are revealed for GALs by analyzing the maximum Seebeck coefficient with a tuned gate voltage and thus shifted Fermi levels. It shows that the scattering from pore-edge-trapped charges is dominant. For thermoelectric interests, the gate-voltage-dependent power factor for a GAL with the square pattern can reach as high as 554 μW/cm⋅ K 2 at 400 K. With their high thermal conductivities and power factors, these GALs can be well suitable for “active coolers” within electronic devices, where heat generated at the hot spot can be removed with both passive heat conduction and active Peltier cooling.