Screening limited switching performance of multilayer 2D semiconductor FETs: the case for SnS

Abstract

Gate tunable p-type multilayer tin mono-sulfide (SnS) field-effect transistor (FET) devices with SnS thickness between 50 and 100 nm were fabricated and studied to understand their performances. The devices showed anisotropic inplane conductance and room temperature field effect mobilities ~5 - 10 cm${}^2$/Vs. However, the devices showed appreciable OFF state conductance and an ON-OFF ratio ~10 at room temperature. The weak gate tuning behavior in the depletion regime of SnS devices is explained by the finite carrier screening length effect which causes the existence of a conductive surface layer from intrinsic defects induced holes in SnS. Through etching and n-type surface doping by Cs2CO3 to reduce/compensate the not-gatable holes near SnS flake's top surface, the devices gained an order of magnitude improvement in the ON-OFF ratio and hole Hall mobility ~ 100 cm${}^2$/Vs at room temperature is observed. This work suggests that in order to obtain effective switching and low OFF state power consumption, two-dimensional (2D) semiconductor based depletion mode FETs should limit their thickness to within the Debye screening length of carriers in the semiconductor.

References in corpus (18)

• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
• Van der Waals heterostructures
• Black phosphorus field-effect transistors
• Phosphorene: A New 2D Material with High Carrier Mobility
• The Nature of Electronic States in Atomically Thin MoS2 Field-Effect Transistors
• Field-effect transistors and intrinsic mobility in ultra-thin MoSe2 layers
• First-principles study of anisotropic thermoelectric transport properties of IV-VI semiconductor compounds SnSe and SnS
• Measurement of mobility in dual-gated MoS2 transistors
• Intrinsic electron mobility exceeding 1000 cm${}^2$/Vs in multilayer InSe FETs
• Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe2, MoS2, and MoSe2 Transistors
• Transistors with Chemically Synthesized Layered Semiconductor WS2 Exhibiting 105 Room Temperature Modulation and Ambipolar Behavior
• Quasiparticle band structures and thermoelectric transport properties of p-type SnSe
• Valleytronics in Tin (II) Sulfide
• Hall and field-effect mobilities in few layered $p$-WSe${}_2$ field-effect transistors
• n-type conversion of SnS by isovalent ion substitution: Geometrical doping as a new doping route
• Observation of intervalley quantum interference in epitaxial monolayer WSe2
• Gate-modulated conductance of few-layer WSe_2 field-effect transistors in the subgap regime: Schottky barrier transistor and subgap impurity states

Cited by in corpus (5)

• Recent Advances in Two-Dimensional Metal Monochalcogenides
• Accumulation-mode two-dimensional field-effect transistor: Operation mechanism and thickness scaling rule
• Micrometer-scale monolayer SnS growth by physical vapor deposition
• Anisotropic circular photogalvanic effect in colloidal tin sulfide nanosheets
• Non-stoichiometry in SnS: How it affects thin-film morphology and electrical properties