title: Electrical characteristics of multilayer MoS2 FET's with MoS2/graphene heterojunction contacts.
abstract: The electrical properties of multilayer MoS2/graphene heterojunction transistors are investigated. Temperature-dependent I-V measurements indicate the concentration of unintentional donors in exfoliated MoS2 to be 3.57 × 10(11) cm(-2), while the ionized donor concentration is determined as 3.61 × 10(10) cm(-2). The temperature-dependent measurements also reveal two dominant donor levels, one at 0.27 eV below the conduction band and another located at 0.05 eV below the conduction band. The I-V characteristics are asymmetric with drain bias voltage and dependent on the junction used for the source or drain contact. I-V characteristics of the device are consistent with a long channel one-dimensional field-effect transistor model with Schottky contact. Utilizing devices, which have both graphene/MoS2 and Ti/MoS2 contacts, the Schottky barrier heights of both interfaces are measured. The charge transport mechanism in both junctions was determined to be either thermionic-field emission or field emission depending on bias voltage and temperature. On the basis of a thermionic field emission model, the barrier height at the graphene/MoS2 interface was determined to be 0.23 eV, while the barrier height at the Ti/MoS2 interface was 0.40 eV. The value of Ti/MoS2 barrier is higher than previously reported values, which did not include the effects of thermionic field emission.
authors: School of Electrical and Computer Engineering, Cornell University , Ithaca, New York 14853, United States.
authors: Joon Young
authors: JY
authors: Kwak
authors: Jeonghyun
authors: J
authors: Hwang
authors: Brian
authors: B
authors: Calderon
authors: Hussain
authors: H
authors: Alsalman
authors: Nini
authors: N
authors: Munoz
authors: Brian
authors: B
authors: Schutter
authors: Michael G
authors: MG
authors: Spencer