Department of Chemistry, Tokyo Institute of Technology, 2-12-1-W4-1, Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
Phys Chem Chem Phys. 2014 Mar 7;16(9):4313-9. doi: 10.1039/c3cp54669a.
We investigated the device characteristics of a graphene field effect transistor (FET) of which interfaces were controlled by a self-assembled monolayer (SAM). Electrical transport measurements together with Raman spectroscopy characterizations for bilayer graphene (BLG) and single layer graphene (SLG) on micro-patterned SAM (mp-SAM), respectively, elucidate spatial carrier modulations on the graphene sheets driven by mp-SAM. The SLG-mp-SAM-FET device exhibits unconventional graphene p-n junction characteristics depending on the polarity of source-drain voltage. The observed characteristics can be interpreted as a velocity saturation of hole carriers coupled with polaron states, of which phonon energy is around 30 meV, on the SAM molecules at the graphene p-n junction. The SAM-based micro fabrication techniques presented in this report not only provide a spatial control of electronic properties for graphene but also lend a new perspective in the understanding of graphene-substrate interface based molecular self-assembled systems.
我们研究了由自组装单分子层（SAM）控制界面的石墨烯场效应晶体管（FET）的器件特性。对微图案化 SAM（mp-SAM）上的双层石墨烯（BLG）和单层石墨烯（SLG）进行了电输运测量和拉曼光谱特性分析，阐明了mp-SAM 驱动下石墨烯片上的空间载流子调制。根据源漏电压的极性，SLG-mp-SAM-FET 器件表现出非传统的石墨烯 p-n 结特性。观察到的特性可以解释为在石墨烯的 p-n 结处的 SAM 分子上的空穴载流子的速度饱和与极化子态耦合，其声子能量约为 30meV。本报告中提出的基于 SAM 的微制造技术不仅为石墨烯提供了电子特性的空间控制，而且为理解基于石墨烯-衬底界面的分子自组装系统提供了新的视角。
