Xia Fengnian, Mueller Thomas, Golizadeh-Mojarad Roksana, Freitag Marcus, Lin Yu-ming, Tsang James, Perebeinos Vasili, Avouris Phaedon
IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Nano Lett. 2009 Mar;9(3):1039-44. doi: 10.1021/nl8033812.
We measure the channel potential of a graphene transistor using a scanning photocurrent imaging technique. We show that at a certain gate bias, the impact of the metal on the channel potential profile extends into the channel for more than one-third of the total channel length from both source and drain sides; hence, most of the channel is affected by the metal. The potential barrier between the metal-controlled graphene and bulk graphene channel is also measured at various gate biases. As the gate bias exceeds the Dirac point voltage, VDirac, the original p-type graphene channel turns into a p-n-p channel. When light is focused on the p-n junctions, an impressive external responsivity of 0.001 A/W is achieved, given that only a single layer of atoms are involved in photon detection.
我们使用扫描光电流成像技术测量了石墨烯晶体管的沟道电势。我们发现，在特定的栅极偏压下，金属对沟道电势分布的影响从源极和漏极两侧延伸到沟道总长度的三分之一以上；因此，大部分沟道都受到金属的影响。我们还在不同的栅极偏压下测量了金属控制的石墨烯与体相石墨烯沟道之间的势垒。当栅极偏压超过狄拉克点电压VDirac时，原来的p型石墨烯沟道转变为p-n-p沟道。当光聚焦在p-n结上时，鉴于仅单层原子参与光子检测，可实现高达0.001 A/W的可观外部响应率。
