nl2021575_si_001.pdf (411.9 kB)
Ambipolar MoS2 Thin Flake Transistors
journal contribution
posted on 2012-03-14, 00:00 authored by Yijin Zhang, Jianting Ye, Yusuke Matsuhashi, Yoshihiro IwasaField effect transistors (FETs) made of thin flake single
crystals
isolated from layered materials have attracted growing interest since
the success of graphene. Here, we report the fabrication of an electric
double layer transistor (EDLT, a FET gated by ionic liquids) using
a thin flake of MoS2, a member of the transition metal
dichalcogenides, an archetypal layered material. The EDLT of the thin
flake MoS2 unambiguously displayed ambipolar operation,
in contrast to its commonly known bulk property as an n-type semiconductor. High-performance transistor operation characterized
by a large “ON” state conductivity in the order of ∼mS
and a high on/off ratio >102 was realized for both hole
and electron transport. Hall effect measurements revealed mobility
of 44 and 86 cm2 V–1 s–1 for electron and hole, respectively. The hole mobility
is twice the value of the electron mobility, and the density of accumulated
carrier reached 1 × 1014 cm–2, which
is 1 order of magnitude larger than conventional FETs with solid dielectrics.
The high-density carriers of both holes and electrons can create metallic
transport in the MoS2 channel. The present result is not
only important for device applications with new functionalities, but
the method itself would also act as a protocol to study this class
of material for a broader scope of possibilities in accessing their
unexplored properties.