Enhanced thermoelectric performance of graphene p−n junction nanoribbon

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-07-24 DOI:10.1016/j.physe.2024.116057

Ting-Ting Song, Ning-Xuan Yang, Rui Wang, Hui Liao, Chun-Yan Song, Xue-Yan Cheng

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Abstract

We study the thermoelectric transport of the graphene $p - n$ junction under the perpendicular magnetic field. The Seebeck coefficient $S_{c}$ , the thermoelectrical figure of merit $Z T$ and the power-generation efficiency $η$ are obtained by the Landauer–Büttiker formula combined with the nonequilibrium Green’s function method. Compared to the perfect graphene system, the graphene $p - n$ junction has a zero-transport coefficient plateau (or the transport gap). The sudden jump of the transmission coefficient near the transport gap edge lead to very larger peaks of the $S_{c}$ and $Z T$ . Especially in the presence of a magnetic field, the perpendicular magnetic field applied to the $p - n$ junction strongly suppresses the conductance, and enhances the Seebeck coefficient $S_{c}$ and increases the $Z T$ . Moreover, it is found that the Seebeck coefficient $S_{c}$ and $Z T$ are strongly dependent on the applied perpendicular magnetic field $ϕ$ , the potential drop in the center region of the $p - n$ junction and the center region length $M$ of the $p - n$ junction. This means that the thermoelectric performance of the graphene $p - n$ junction can be easily regulated by changing the magnetic field and the center region lengths of the $p - n$ junction. Finally, the power-generation efficiency $η$ of the graphene $p - n$ junction as a power generator is calculated. It is found that when the Carnot power-generation efficiency is greater than 30%, $Z T_{M}$ can still be greater than 10. The large $Z T_{M}$ value also maintains a high power-generation efficiency, which indicates that the graphene $p - n$ junction has potential applications as thermoelectric devices.

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增强石墨烯[式略]结纳米带的热电性能

我们研究了垂直磁场下石墨烯结的热电传输。通过 Landauer-Büttiker 公式结合非平衡格林函数法，得到了塞贝克系数、热电功勋值和发电效率。与完美的石墨烯体系相比，石墨烯结具有零传输系数高原（或传输间隙）。传输间隙边缘附近传输系数的突然跃迁会导致和的峰值非常大。特别是在有磁场的情况下，施加在结上的垂直磁场会强烈抑制电导，并增强塞贝克系数和增加......。此外，研究还发现塞贝克系数和强烈依赖于所施加的垂直磁场、结中心区域的电位降以及结中心区域的长度。这意味着可以通过改变磁场和结中心区域的长度来轻松调节石墨烯结的热电性能。最后，计算了石墨烯结作为发电机的发电效率。结果发现，当卡诺发电效率大于 30% 时，仍可大于 10。大值的同时还能保持较高的发电效率，这表明石墨烯结作为热电器件具有潜在的应用前景。

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来源期刊

Physica E-low-dimensional Systems & Nanostructures 物理-纳米科技

CiteScore

7.30

自引率

6.10%

发文量

356

审稿时长

65 days

期刊介绍： Physica E: Low-dimensional systems and nanostructures contains papers and invited review articles on the fundamental and applied aspects of physics in low-dimensional electron systems, in semiconductor heterostructures, oxide interfaces, quantum wells and superlattices, quantum wires and dots, novel quantum states of matter such as topological insulators, and Weyl semimetals. Both theoretical and experimental contributions are invited. Topics suitable for publication in this journal include spin related phenomena, optical and transport properties, many-body effects, integer and fractional quantum Hall effects, quantum spin Hall effect, single electron effects and devices, Majorana fermions, and other novel phenomena. Keywords: • topological insulators/superconductors, majorana fermions, Wyel semimetals; • quantum and neuromorphic computing/quantum information physics and devices based on low dimensional systems; • layered superconductivity, low dimensional systems with superconducting proximity effect; • 2D materials such as transition metal dichalcogenides; • oxide heterostructures including ZnO, SrTiO3 etc; • carbon nanostructures (graphene, carbon nanotubes, diamond NV center, etc.) • quantum wells and superlattices; • quantum Hall effect, quantum spin Hall effect, quantum anomalous Hall effect; • optical- and phonons-related phenomena; • magnetic-semiconductor structures; • charge/spin-, magnon-, skyrmion-, Cooper pair- and majorana fermion- transport and tunneling; • ultra-fast nonlinear optical phenomena; • novel devices and applications (such as high performance sensor, solar cell, etc); • novel growth and fabrication techniques for nanostructures

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