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arXiv · 1406.3919

Suspending Effect on Low-Frequency Charge Noise in Graphene Quantum Dot

Xiang-Xiang Song·Hai-Ou Li·Jie You·Tian-Yi Han·Gang Cao·Tao Tu·Ming Xiao·Guang-Can Guo·Hong-Wen Jiang·Guo-Ping Guo
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Abstract

Charge noise is critical in the performance of gate-controlled quantum dots (QDs). Here we show the 1/f noise for a microscopic graphene QD is substantially larger than that for a macroscopic graphene field-effect transistor (FET), increasing linearly with temperature. To understand its origin, we suspended the graphene QD above the substrate. In contrast to large area graphene FETs, we find that a suspended graphene QD has an almost-identical noise level as an unsuspended one. Tracking noise levels around the Coulomb blockade peak as a function of gate voltage yields potential fluctuations of order 1 "{\mu}eV", almost one order larger than in GaAs/GaAlAs QDs. Edge states rather than substrate-induced disorders, appear to dominate the 1/f noise, thus affecting the coherency of graphene nano-devices.

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Xiang-Xiang Song, Hai-Ou Li, Jie You, Tian-Yi Han, Gang Cao, Tao Tu, Ming Xiao, Guang-Can Guo, Hong-Wen Jiang, Guo-Ping Guo. 2014-06-16. Suspending Effect on Low-Frequency Charge Noise in Graphene Quantum Dot. https://doi.org/10.1038/srep08142

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