Photocurrent Switching of Monolayer MoS<sub>2</sub> Using a Metal-Insulator Transition.

Lee, Jin Hee; Gul, Hamza Zad; Kim, Hyun; Moon, Byoung Hee; Adhikari, Subash; Kim, Jung Ho; Choi, Homin; Lee, Young Hee et al. · Nano Lett · 2017

basic_science · Level V

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Abstract

We achieve switching on/off the photocurrent of monolayer molybdenum disulfide (MoS<sub>2</sub>) by controlling the metal-insulator transition (MIT). N-type semiconducting MoS<sub>2</sub> under a large negative gate bias generates a photocurrent attributed to the increase of excess carriers in the conduction band by optical excitation. However, under a large positive gate bias, a phase shift from semiconducting to metallic MoS<sub>2</sub> is caused, and the photocurrent by excess carriers in the conduction band induced by the laser disappears due to enhanced electron-electron scattering. Thus, no photocurrent is detected in metallic MoS<sub>2</sub>. Our results indicate that the photocurrent of MoS<sub>2</sub> can be switched on/off by appropriately controlling the MIT transition by means of gate bias.