Piccinini Giulia, Mišeikis Vaidotas, Novelli Pietro, Watanabe Kenji, Taniguchi Takashi, Polini Marco, Coletti Camilla, Pezzini Sergio
NEST, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy.
Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy.
Nano Lett. 2022 Jul 13;22(13):5252-5259. doi: 10.1021/acs.nanolett.2c01114. Epub 2022 Jul 1.
To realize the applicative potential of 2D twistronic devices, scalable synthesis and assembly techniques need to meet stringent requirements in terms of interface cleanness and twist-angle homogeneity. Here, we show that small-angle twisted bilayer graphene assembled from separated CVD-grown graphene single-crystals can ensure high-quality transport properties, determined by a device-scale-uniform moiré potential. Via low-temperature dual-gated magnetotransport, we demonstrate the hallmarks of a 2.4°-twisted superlattice, including tunable regimes of interlayer coupling, reduced Fermi velocity, large interlayer capacitance, and density-independent Brown-Zak oscillations. The observation of these moiré-induced electrical transport features establishes CVD-based twisted bilayer graphene as an alternative to "tear-and-stack" exfoliated flakes for fundamental studies, while serving as a proof-of-concept for future large-scale assembly.
为了实现二维扭曲电子器件的应用潜力，可扩展的合成和组装技术需要在界面清洁度和扭曲角均匀性方面满足严格要求。在此，我们表明，由分离的化学气相沉积（CVD）生长的石墨烯单晶组装而成的小角度扭曲双层石墨烯，可确保高质量的输运特性，这由器件尺度均匀的莫尔势决定。通过低温双栅磁输运，我们展示了2.4°扭曲超晶格的特征，包括层间耦合的可调谐区域、降低的费米速度、大的层间电容以及与密度无关的布朗-扎克振荡。这些莫尔诱导的电输运特征的观测，确立了基于CVD的扭曲双层石墨烯作为用于基础研究的“撕裂并堆叠”剥离薄片的替代物，同时也为未来的大规模组装提供了概念验证。
