Extremely high mobility over 5000 cm2/Vs obtained from MoS2 nanosheet transistor with NiOx Schottky gate

TL;DR

This paper reports the achievement of extremely high carrier mobilities in MoS2 nanosheet transistors with NiOx Schottky gates, surpassing previous records and providing insights into thickness-dependent mobility behavior.

Contribution

First demonstration of MoS2 MESFETs with NiOx Schottky gates achieving mobilities over 5000 cm2/Vs, minimizing interface interference and explaining thickness effects.

Findings

Achieved mobilities of 6000, 3500, and 2800 cm2/Vs in single-, double-, and triple-layer MoS2.

Mobility is less affected by gate voltage due to Schottky contact design.

Thickness influences mobility through electron scattering mechanisms.

Abstract

Molybdenum disulfide (MoS2) nanosheet, one of two dimensional (2D) semiconductors, has recently been regarded as a promising material to break through the limit of present semiconductors including graphene. However, its potential in carrier mobility has still been depreciated since the field-effect mobilities have only been measured from metal-insulator-semiconductor field effect transistors (MISFETs), where the transport behavior of conducting carriers located at the insulator/MoS2 interface is unavoidably interfered by the interface traps and gate voltage. Here, we for the first time report MoS2-based metal semiconductor field-effect transistors (MESFETs) with NiOx Schottky electrode, where the maximum mobilities or carrier transport behavior of the Schottky devices may hardly be interfered by on-state gate field. Our MESFETs with single-, double-, and triple-layered MoS2 respectively demonstrate high mobilities of 6000, 3500, and 2800 cm2/Vs at a certain low threshold voltage of -1 ~ -2 V. The thickness-dependent mobility difference in MESFETs was theoretically explained with electron scattering reduction mechanisms.