Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, China.
ACS Nano. 2011 Jun 28;5(6):5031-7. doi: 10.1021/nn201115p. Epub 2011 May 6.
High-performance graphene field-effect transistors (G-FETs) are fabricated with carrier mobility of up to 5400 cm(2)/V·s and top-gate efficiency of up to 120 (relative to that of back gate with 285 nm SiO(2)) simultaneously through growing high-quality Y(2)O(3) gate oxide at high oxidizing temperature. The transconductance normalized by dimension and drain voltage is found to reach 7900 μF/V·s, which is among the largest of the published graphene FETs. In an as-fabricated graphene FET with a gate length of 310 nm, a peak transconductance of 0.69 mS/μm is realized, but further improvement is seriously hindered by large series resistance. Benefiting from highly efficient gate control over the graphene channel, the Dirac point voltage of the graphene FETs is shown to be designable via simply selecting a gate metal with an appropriate work function. It is demonstrated that the Dirac point voltage of the graphene FETs can be adjusted from negative to positive, respectively, via changing the gate material from Ti to Pd.
通过在高温下生长高质量的 Y(2)O(3)栅氧化层，同时获得高达 5400 cm(2)/V·s 的载流子迁移率和高达 120 的顶栅效率（相对于具有 285nm SiO(2)的背栅），制造出高性能石墨烯场效应晶体管（G-FET）。通过尺寸和漏极电压归一化的跨导被发现达到 7900 μF/V·s，这是已发表的石墨烯 FET 中的最大值之一。在栅长为 310nm 的制造的石墨烯 FET 中，实现了 0.69mS/μm 的峰值跨导，但由于大的串联电阻，进一步的改进受到严重阻碍。由于对石墨烯沟道的高效栅极控制，通过简单地选择具有适当功函数的栅极金属，可以设计石墨烯 FET 的狄拉克点电压。结果表明，通过将栅极材料从 Ti 变为 Pd，石墨烯 FET 的狄拉克点电压可以分别从负变为正进行调节。
