Phase-engineered low-resistance contacts for ultrathin MoS2 transistors

Rajesh Kappera, Damien Voiry, Sibel Ebru Yalcin, Brittany Branch, Gautam Gupta, Aditya D. Mohite, Manish Chhowalla

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764 Citations (Scopus)

Abstract

Ultrathin molybdenum disulphide (MoS2) has emerged as an interesting layered semiconductor because of its finite energy bandgap and the absence of dangling bonds. However, metals deposited on the semiconducting 2H phase usually form high-resistance (0.7 kω μm-10 kω μm) contacts, leading to Schottky-limited transport. In this study, we demonstrate that the metallic 1T phase of MoS2 can be locally induced on semiconducting 2H phase nanosheets, thus decreasing contact resistances to 200-300 ω μm at zero gate bias. Field-effect transistors (FETs) with 1T phase electrodes fabricated and tested in air exhibit mobility values of ∼50 cm2V-1s-1, subthreshold swing values below 100 mV per decade, on/off ratios of >107, drive currents approaching ∼100 μA μm-1, and excellent current saturation. The deposition of different metals has limited influence on the FET performance, suggesting that the 1T/2H interface controls carrier injection into the channel. An increased reproducibility of the electrical characteristics is also obtained with our strategy based on phase engineering of MoS2.

Original languageEnglish
Pages (from-to)1128-1134
Number of pages7
JournalNature Materials
Volume13
Issue number12
DOIs
Publication statusPublished - Dec 1 2014

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ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Kappera, R., Voiry, D., Yalcin, S. E., Branch, B., Gupta, G., Mohite, A. D., & Chhowalla, M. (2014). Phase-engineered low-resistance contacts for ultrathin MoS2 transistors. Nature Materials, 13(12), 1128-1134. https://doi.org/10.1038/nmat4080