title: Metal-semiconductor barrier modulation for high photoresponse in transition metal dichalcogenide field effect transistors.
abstract: A gate-controlled metal-semiconductor barrier modulation and its effect on carrier transport were investigated in two-dimensional (2D) transition metal dichalcogenide (TMDC) field effect transistors (FETs). A strong photoresponse was observed in both unipolar MoS2 and ambipolar WSe2 FETs (i) at the high drain voltage due to a high electric field along the channel for separating photo-excited charge carriers and (ii) at the certain gate voltage due to the optimized barriers for the collection of photo-excited charge carriers at metal contacts. The effective barrier height between Ti/Au and TMDCs was estimated by a low temperature measurement. An ohmic contact behavior and drain-induced barrier lowering (DIBL) were clearly observed in MoS2 FET. In contrast, a Schottky-to-ohmic contact transition was observed in WSe2 FET as the gate voltage increases, due to the change of majority carrier transport from holes to electrons. The gate-dependent barrier modulation effectively controls the carrier transport, demonstrating its great potential in 2D TMDCs for electronic and optoelectronic applications.
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Hua-Min
authors: HM
authors: Li
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Dae-Yeong
authors: DY
authors: Lee
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Min Sup
authors: MS
authors: Choi
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Deshun
authors: D
authors: Qu
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Xiaochi
authors: X
authors: Liu
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Chang-Ho
authors: CH
authors: Ra
authors: Samsung-SKKU Graphene Center (SSGC), SKKU Advanced Institute of Nano Technology (SAINT), Department of Nano Science and Technology, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 440-746, Korea.
authors: Won Jong
authors: WJ
authors: Yoo