Krasavin S E, Osipov V A
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia, 141980.
Sci Rep. 2022 Aug 25;12(1):14553. doi: 10.1038/s41598-022-18604-y.
We have revealed the decisive role of grain-boundary-induced strain fields in electron scattering in polycrystalline graphene. To this end, we have formulated the model based on Boltzmann transport theory which properly takes into account the microscopic structure of grain boundaries (GB) as a repeated sequence of heptagon-pentagon pairs. We show that at naturally low GB charges the strain field scattering dominates and leads to physically reasonable and, what is important, experimentally observable values of the electrical resistivity. It ranges from 0.1 to 10 k[Formula: see text] [Formula: see text] for different types of symmetric GBs with a size of 1 [Formula: see text]m and has a strong dependence on misorientation angle. For low-angle highly charged GBs, two scattering mechanisms may compete. The resistivity increases markedly with decreasing GB size and reaches values of 60 k[Formula: see text] [Formula: see text]m and more. It is also very sensitive to the presence of irregularities modeled by embedding of partial disclination dipoles. With significant distortion, we found an increase in resistance by more than an order of magnitude, which is directly related to the destruction of diffraction on the GB. Our findings may be of interest both in the interpretation of experimental data and in the design of electronic devices based on poly- and nanocrystalline graphene.
我们揭示了晶界诱导应变场在多晶石墨烯电子散射中的决定性作用。为此，我们基于玻尔兹曼输运理论建立了模型，该模型恰当地考虑了晶界（GB）的微观结构，即七边形 - 五边形对的重复序列。我们表明，在自然低的晶界电荷情况下，应变场散射占主导地位，并导致电阻率在物理上合理且重要的是在实验上可观测的值。对于尺寸为1微米的不同类型对称晶界，其范围为0.1至10 kΩ·μm，并且强烈依赖于取向差角。对于低角度高电荷晶界，两种散射机制可能相互竞争。电阻率随着晶界尺寸的减小而显著增加，达到60 kΩ·μm及更高的值。它对通过嵌入部分位错偶极子建模的不规则性的存在也非常敏感。在存在显著畸变的情况下，我们发现电阻增加了一个多数量级，这与晶界上衍射的破坏直接相关。我们的发现对于解释实验数据以及基于多晶和纳米晶石墨烯的电子器件设计都可能具有重要意义。
