hBN封装的石墨烯器件中多个Dirac锥体处的1 / <i>f</i>噪声的可调谐性,Nano Letters

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hBN封装的石墨烯器件中多个Dirac锥体处的1 / f噪声的可调谐性
Nano Letters ( IF 9.6 ) Pub Date : 2016-01-14 00:00:00 , DOI: 10.1021/acs.nanolett.5b04116
Chandan Kumar ₁ , Manabendra Kuiri ₁ , Jeil Jung ₂ , Tanmoy Das ₁ , Anindya Das ₁

Affiliation

六方氮化硼（hBN）-石墨烯异质结构中多个狄拉克锥的出现特别吸引人，因为与主要狄拉克锥相比，它具有更高的景观潜力，具有更高的通用运输性能。然而，克隆的狄拉克锥的传输系数尚未完全表征，许多开放的问题，包括电荷动力学的演变和造成它们的杂质散射，仍未得到探讨。迄今为止，尚未在双栅极hBN-石墨烯-hBN设备中进行有可能解决这些问题的噪声测量。在这里，我们介绍低频1 / f在双门控几何结构中，hBN封装的单层和双层石墨烯中多个Dirac锥体处的噪声测量。我们的研究结果表明，通过改变载流子浓度以及修改双层石墨烯中的能带结构，可以将石墨烯中的低频噪声调谐超过两个数量级。我们发现，与单层石墨烯器件中的主要狄拉克锥相比，在克隆的狄拉克锥上的噪声得到了令人惊讶的抑制，而对于带隙开放的双层石墨烯，噪声得到了显着增强。通过使用紧束缚模型计算介电函数来解释结果。我们的结果还表明，1 / f在双门控几何结构中，在hBN保护的设备中，噪声确实遵循了Hooge的经验公式。我们还首次提出了石墨烯器件双极态下的噪声数据。

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Tunability of 1/f Noise at Multiple Dirac Cones in hBN Encapsulated Graphene Devices

The emergence of multiple Dirac cones in hexagonal boron nitride (hBN)–graphene heterostructures is particularly attractive because it offers potentially better landscape for higher and versatile transport properties than the primary Dirac cone. However, the transport coefficients of the cloned Dirac cones is yet not fully characterized and many open questions, including the evolution of charge dynamics and impurity scattering responsible for them, have remained unexplored. Noise measurements, having the potential to address these questions, have not been performed to date in dual-gated hBN–graphene–hBN devices. Here, we present the low-frequency 1/f noise measurements at multiple Dirac cones in hBN encapsulated single and bilayer graphene in dual-gated geometry. Our results reveal that the low-frequency noise in graphene can be tuned by more than two-orders of magnitude by changing carrier concentration as well as by modifying the band structure in bilayer graphene. We find that the noise is surprisingly suppressed at the cloned Dirac cone compared to the primary Dirac cone in single layer graphene device, while it is strongly enhanced for the bilayer graphene with band gap opening. The results are explained with the calculation of dielectric function using tight-binding model. Our results also indicate that the 1/f noise indeed follows the Hooge’s empirical formula in hBN-protected devices in dual-gated geometry. We also present for the first time the noise data in bipolar regime of a graphene device.

更新日期：2016-01-14

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