1/ f Noise in MoS 2 Field Effect Transistors with Various Layer Thicknesses
- PDF / 992,169 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 64 Downloads / 179 Views
1/f Noise in MoS2 Field Effect Transistors with Various Layer Thicknesses Suprem R. Das1,2,*, Jiseok Kwon1,2 and David B. Janes1,2 1 School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, U.S.A 2 Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, U.S.A * ( contact author [email protected]) ABSTRACT 1/f noise in semiconductor devices and circuits provides important information regarding quality of the interface as well as the transport mechanism. In 1D and 2D channel materials, 1/f noise also provides information on stability under ambient conditions, including effects of contaminants adsorbed on the surface. In addition, noise levels are important in evaluating suitability of the device for analog and digital applications. In this work, we have fabricated back-gated field-effect transistors (FETs) using various thicknesses of mechanically exfoliated MoS2 flakes (bilayer and 15 layer flakes) and studied the 1/f noise under ambient conditions. The on-current of the devices scales with the number of layers. The Hooge parameters inferred from the measured noise amplitudes and calculated carrier densities are comparable to prior reports on devices such as CNTs and graphene FETs, even when measured under ambient conditions. The effect of channel and contacts on both the conductance and noise can be inferred from bias-dependent current and noise measurements. INTRODUCTION 1/f noise (or more generally, flicker noise) is associated with signals in electrical, vibrational, acoustic and visual occurrences and is prevalent in wide variety of circumstances starting originally from the discovery of vacuum tubes by Schottky and Johnson to transport in semiconductor devices, music and speech to nonstationarity in human heart rate [1-5]. While the ubiquity of 1/f noise in various physical systems is scientifically interesting, this report particularly focuses on 1/f noise in nanoscale FETs with recently discovered MoS2 2D-channel material. The mechanisms of 1/f noise in bulk materials and field-effect transistors are based on two widely accepted models for electronic transport: (a) McWhorter carrier number fluctuation model and (b) Hooge mobility fluctuation model [6-9]. 1/f noise was originally considered as a bulk effect for a uniform three dimensional channel material. On the other hand the emergence of various types of low dimensional semiconducting channel materials such as nanotubes (1D), semiconducting nanowires (quasi-1D), graphene (2D), transition-metal dichalcogenides (2D) such as MoS2, motivated by complementary metal-oxide-semiconductor (CMOS) aggressive downscaling, has broadened the scope of 1/f noise study beyond the traditional understanding. Furthermore, the contributions of 1/f noise from channel as well as from S/D contact, effect of passivation etc. have become new areas of study in modern low-dimensional nanoscale devices. MoS2 and related transition metal dichalcogenide (TMDC) layered materials have recently gained significant attention as alternate cha
Data Loading...
