Metal-graphene-metal photodetectors utilize photocurrent generated near the graphene/metal junctions and have many advantages including high speed and broad-band operation. Here, we report on photocurrent generation at ABA/ABC stacking domain junctions in tri-layer graphene with a responsivity of 0.18 A/W. Unlike usual metal-graphene-metal devices, the photocurrent is generated in the middle of the graphene channel, not confined to the vicinity of the metal electrodes. The magnitude and the direction of the photocurrent depend on the back-gate bias. Theoretical calculations show that there is a built-in band offset between the two stacking domains, and the dominant mechanism of the photocurrent is the photo-thermoelectric effect due to the Seebeck coefficient difference.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea grants funded by the Ministry of Science, ICT and Future Planning of Korea (No. 2011-0017605 and 2012R1A2A2A01045496 ) and grants from the Center for Advanced Soft Electronics under the Global Frontier Research Program of the MSIP (No. 2011-0031630 and No. 2011-0031640 ). Computations were supported by the CAC of KIAS. M.K. is supported by the TJ Park Science Fellowship of POSCO TJ Park Foundation.
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