Department of Mechanical Engineering, Yonsei University, Seoul 120-749, Republic of Korea.
Nanoscale. 2017 Oct 26;9(41):15934-15944. doi: 10.1039/c7nr04571a.
Graphene, a two-dimensional material with a honeycomb lattice, has been promoted as a next generation material because of its ultrafast charge carriers and superior electrical properties. Hexagonal boron nitride (h-BN) is an insulator explored as an ideal substrate for graphene with lattice-matching. Using raido-frequency (RF) transmission measurement which provides specific characteristics of carrier scattering in a device, we profoundly investigated the electrical properties of quasi-free standing graphene on h-BN. RF devices with graphene supported and encapsulated with h-BN were fabricated to analyze the RF signal at low temperatures from 100 to 300 K. We demonstrated the carrier behavior in graphene with thermally excited carriers and acoustic photon scattering according to heat energy. Both h-BN supported and encapsulated graphene showed a significant enhancement in RF transmission, which is close to a gold interconnector. Our device with graphene on h-BN exhibited concealed nonlinear characteristics at a specific temperature of 180 K due to the internal effects of acoustic phonon scattering, while a usual device with graphene on SiO/Si provided a linear variation. To anticipate the potential for electronic applications, the electrical circuit properties such as impedance, resistance, and inductance were extracted from the results of RF measurement.
石墨烯是一种具有蜂窝晶格的二维材料，因其超快的电荷载流子和优异的电学性能而被推广为下一代材料。六方氮化硼（h-BN）是一种被探索用作与晶格匹配的石墨烯理想衬底的绝缘体。我们使用射频（RF）传输测量，该测量提供了器件中载流子散射的特定特性，深入研究了在 h-BN 上的准自由-standing 石墨烯的电学性质。我们制备了具有石墨烯支撑和 h-BN 封装的 RF 器件，以在 100 到 300 K 的低温下分析 RF 信号。我们根据热能展示了热激发载流子和声学光子散射的石墨烯中的载流子行为。h-BN 支撑和封装的石墨烯都表现出 RF 传输的显著增强，接近于金互连器。我们在 h-BN 上的石墨烯器件由于声子散射的内部效应，在特定的 180 K 温度下表现出隐蔽的非线性特性，而通常在 SiO2/Si 上的石墨烯器件则提供线性变化。为了预测电子应用的潜力，从 RF 测量的结果中提取了诸如阻抗、电阻和电感等电路特性。
