The paper reports on the charge transport in the sandwich-like graphene / Co nanoparticles / graphene structure (G/CoNPs/G). It is fabricated by combining the electrochemical deposition of Co nanoparticles onto a single layer CVD graphene and their capping with another graphene layer. The isolated semi-spherical, surface oxidized Co NPs of 250 nm in diameter serve as a support for the top graphene layer and provide its suspended state confirmed by atomic force microscopy revealing periodic ripples on its surface. A high optical transparency of 92.4% is found for the G/CoNPs/G sandwich. The observed twofold reduction in the sheet resistance with a ∼ 1.5 times increase in the positive magnetoresistive effect for G/CoNPs/G compared to the pristine graphene is attributed to the suppression of carrier scattering due to the substrate. From the Hall effect measurements, a predominant role of the top graphene layer in the charge transport in G/CoNPs/G is established, with a significantly increased carrier mobility µ∼1800 cm²/(V·s). An elastic intervalley scattering length estimated from the magnetoresistance results is found to be three times increased in G/CoNPs/G, indicating that the top graphene layer is almost unaffected by the substrate. The proposed technology looks promising for possible optoelectronic and magneto-optical applications.

该论文报告了夹心状石墨烯 / Co 纳米粒子 / 石墨烯中的电荷传输结构（G/CoNPs/G）。它是通过将 Co 纳米颗粒的电化学沉积结合到单层 CVD 石墨烯上并将它们与另一个石墨烯层覆盖来制造的。直径为 250 nm 的孤立的半球形表面氧化 Co NPs 作为顶部石墨烯层的支撑，并通过原子力显微镜确认其悬浮状态，揭示其表面上的周期性波纹。G/CoNPs/G 三明治的光学透明度高达 92.4%。与原始石墨烯相比，观察到的薄层电阻降低了两倍，G/CoNPs/G 的正磁阻效应增加了约 1.5 倍，这归因于基板对载流子散射的抑制。从霍尔效应测量，² /(V·s)。发现根据磁阻结果估计的弹性间隔散射长度在 G/CoNPs/G 中增加了三倍，表明顶部石墨烯层几乎不受基板影响。所提出的技术对于可能的光电和磁光应用看起来很有希望。