Direct Observation of a Gate Tunable Band Gap in Electrical Transport in ABC-Trilayer Graphene.
Direct Observation of a Gate Tunable Band Gap in Electrical Transport in ABC-Trilayer Graphene.
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DOI：
10.1021/acs.nanolett.5b00772
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发表时间：
2015-06
期刊：
影响因子：
10.8
通讯作者：
T. Khodkov;I. Khrapach;M. Craciun;S. Russo
中科院分区：
文献类型：
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作者：
T. Khodkov;I. Khrapach;M. Craciun;S. Russo
很少有层状石墨烯体系，如贝纳尔叠层双层和菱面体(ABC-)叠层三层，提供了打开电场可调能隙的独特可能性。到目前为止，这种能隙已经在光学光谱学中得到了实验证实。本文报道了首次在双门悬浮ABC-三层石墨烯电子输运实验中直接观测到电场可调能隙。通过对电流-电压特性的非线性和电导率的温度依赖性的系统研究，我们证明了这些晶体管的电学响应主要是通过能隙上的热激活输运来决定的。由温度关系和电流电压特性估算的能隙符合临界指数为3/2的理论电场依赖关系。这些实验表明，高质量的多层石墨烯是探索新型可调谐太赫兹光源和探测器的合适候选材料。
Few layer graphene systems such as Bernal stacked bilayer and rhombohedral (ABC-) stacked trilayer offer the unique possibility to open an electric field tunable energy gap. To date, this energy gap has been experimentally confirmed in optical spectroscopy. Here we report the first direct observation of the electric field tunable energy gap in electronic transport experiments on doubly gated suspended ABC-trilayer graphene. From a systematic study of the nonlinearities in current versus voltage characteristics and the temperature dependence of the conductivity, we demonstrate that thermally activated transport over the energy-gap dominates the electrical response of these transistors. The estimated values for energy gap from the temperature dependence and from the current voltage characteristics follow the theoretically expected electric field dependence with critical exponent 3/2. These experiments indicate that high quality few-layer graphene are suitable candidates for exploring novel tunable terahertz light sources and detectors.