Tuning the electrical property via defect engineering of single layer MoS₂ by oxygen plasma

Abstract

We demonstrate that the electrical property of a single layer molybdenum disulfide (MoS 2 ) can be significantly tuned from semiconducting to insulating regime via controlled exposure to oxygen plasma. The mobility, on-current and resistance of single layer MoS 2 devices were varied up to four orders of magnitude by controlling the plasma exposure time. Raman spectroscopy, X-ray photoelectron spectroscopy and density functional theory studies suggest that the significant variation of electronic properties is caused by the creation of insulating MoO 3 -rich disordered domains in the MoS 2 sheet upon oxygen plasma exposure, leading to an exponential variation of resistance and mobility as a function of plasma exposure time. The resistance variation calculated using an effective medium model is in excellent agreement with the measurements. The simple approach described here can be used for the fabrication of tunable two dimensional nanodevices on MoS 2 and other transition metal dichalcogenides.

Quasi-two-dimensional transition metal dichalcogenides: structure, synthesis, properties and applications

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Impact of N-plasma and Ga-irradiation on MoS2 layer in molecular beam epitaxy

“…However, the effect of N Ã 2 -and Ga-irradiation on the 2D layered-MoS 2 in high to ultra-high vacuum (UHV) environment has not been explored. Focusing on MoS 2 , the tunability of doping, [13][14][15][16][17] optical, [18][19][20] and structural, 21 properties of the layered-MoS 2 has been reported by employing the plasma (O Ã 2 or N Ã 2 ) irradiation. However, in most of these studies, $150 Torr of the background utilized during plasma irradiation, whereas in plasma-assisted MBE (PAMBE), low background $10 À6 Torr can be used for tuning the properties of layered-MoS 2 .…”

Topography preserved microwave plasma etching for top-down layer engineering in MoS2and other van der Waals materials

“…Though various etching schemes have been explored, [19][20][21][22][23][24][25][26][27][28][29] a scalable and controllable thickness reduction down to the mono-or few-layer regimes starting from arbitrary thickness and area has not been demonstrated. Methods utilizing material chemistry exploit either harsh chemicals 19 or reactive plasma environment, are material specific.…”

“…Methods utilizing material chemistry exploit either harsh chemicals 19 or reactive plasma environment, are material specific. [21][22][23]28 Physical etching involves high temperature annealing, 25,27 laser assisted thermal ablation 20 or plasma environments, 24,26,29 results in degraded electrical properties. Postetch electrical characterization has not been performed in most cases, except for a few.…”