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arXiv 1909.13484cond-mat.mes-hall
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通过原位减少随机应变波动增强石墨烯的迁移率

Mobility enhancement in graphene by in situ reduction of random strain fluctuations

Lujun Wang, Péter Makk, Simon Zihlmann, Andreas Baumgartner, David I. Indolese, Kenji Watanabe, Takashi Taniguchi, Christian Schönenberger

摘要:

微观波纹在石墨烯中是普遍存在的,即使当放置在原子级平坦的衬底上时。这些导致随机局部应变波动,限制了高质量hBN支撑的石墨烯器件的载流子迁移率。我们目前的运输测量hBN封装的设备,这种应变波动可以在原位减少通过增加平均单轴应变。当将单轴应变的$\sim0.2\%$施加到石墨烯时,观察到载流子迁移率增加了$\sim35\%$,而残留掺杂减少了$\sim39\%$。我们证明了迁移率和残余掺杂之间的强相关性,从我们得出的结论是随机的局部应变波动是限制这些设备中的迁移率的无序的主要来源。我们的研究结果也支持拉曼光谱测量。

英文摘要:

Microscopic corrugations are ubiquitous in graphene even when placed on atomically flat substrates. These result in random local strain fluctuations limiting the carrier mobility of high quality hBN-supported graphene devices. We present transport measurements in hBN-encapsulated devices where such strain fluctuations can be in situ reduced by increasing the average uniaxial strain. When $\sim0.2\%$ of uniaxial strain is applied to the graphene, an enhancement of the carrier mobility by $\sim35\%$ is observed while the residual doping reduces by $\sim39\%$. We demonstrate a strong correlation between the mobility and the residual doping, from which we conclude that random local strain fluctuations are the dominant source of disorder limiting the mobility in these devices. Our findings are also supported by Raman spectroscopy measurements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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