论文标题
Moiré单位电池中的纳米成像光响应
Nano-imaging photoresponse in a moiré unit cell
论文作者
论文摘要
基于石墨烯的Moiré超级晶格最近已成为一类独特的可调固态系统，具有显着的光电活动。超级晶格的局部探测应提供对光响应的显微镜机制和Moiré晶格的确切作用的更深入的见解。在这里，我们采用纳米级探测器来研究微型双层石墨烯的单个Moiré单位细胞内的光响应。我们的测量结果揭示了一种空间丰富的光响应，其符号和幅度受Moiré晶格的精细结构及其在测量接触方面的方向的控制。这导致了强烈的定向效应和莫伊尔域内栅极响应的惊人空间依赖性。测得的光电流点朝着光电诱导的响应的空间曲线和载体密度依赖性，通过与数值模拟的良好一致来进一步证实，该响应得到了进一步的证实。我们的工作表明，亚分差光谱是一种出色的工具，用于揭示Moiré超晶格的光电特性。
Graphene-based moiré superlattices have recently emerged as a unique class of tuneable solid-state systems that exhibit significant optoelectronic activity. Local probing at length scales of the superlattice should provide deeper insight into the microscopic mechanisms of photoresponse and the exact role of the moiré lattice. Here, we employ a nanoscale probe to study photoresponse within a single moiré unit cell of minimally twisted bilayer graphene. Our measurements reveal a spatially rich photoresponse, whose sign and magnitude are governed by the fine structure of the moiré lattice and its orientation with respect to measurement contacts. This results in a strong directional effect and a striking spatial dependence of the gate-voltage response within the moiré domains. The spatial profile and carrier-density dependence of the measured photocurrent point towards a photo-thermoelectric induced response that is further corroborated by good agreement with numerical simulations. Our work shows sub-diffraction photocurrent spectroscopy is an exceptional tool for uncovering the optoelectronic properties of moiré superlattices.
