High-Mobility Holes in Dual-Gated WSe2 Field-Effect Transistors.
We demonstrate dual-gated p-type field-effect transistors (FETs) based on few-layer tungsten diselenide (WSe2) using high work-function platinum source/drain contacts and a hexagonal boron nitride top-gate dielectric. A device topology with contacts underneath the WSe2 results in p-FETs with ION/IOFF ratios exceeding 10(7) and contacts that remain ohmic down to cryogenic temperatures. The output characteristics show current saturation and gate tunable negative differential resistance. The devices show intrinsic hole mobilities around 140 cm(2)/(V s) at room temperature and approaching 4000 cm(2)/(V s) at 2 K. Temperature-dependent transport measurements show a metal-insulator transition, with an insulating phase at low densities and a metallic phase at high densities. The mobility shows a strong temperature dependence consistent with phonon scattering, and saturates at low temperatures, possibly limited by Coulomb scattering or defects.
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Hema C P
HC
Movva
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Amritesh
A
Rai
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Sangwoo
S
Kang
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Kyounghwan
K
Kim
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Babak
B
Fallahazad
National Institute of Materials Science , 1-1 Namiki, Tsukuba, 305-044, Japan.
Takashi
T
Taniguchi
National Institute of Materials Science , 1-1 Namiki, Tsukuba, 305-044, Japan.
Kenji
K
Watanabe
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Emanuel
E
Tutuc
Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States.
Sanjay K
SK
Banerjee
field-effect transistor (FET); hole mobility; metal−insulator transition (MIT); transition metal dichalcogenide (TMD); tungsten diselenide (WSe2)