CNR ExploRA

Articolo in rivista, 2019, ENG, 10.1038/s41928-018-0191-0

Patterning metal contacts on monolayer MoS2 with vanishing Schottky barriers using thermal nanolithography

Zheng X.; Calo A.; Albisetti E.; Liu X.u; Alharbi A. S. M.; Arefe G.; Liu X.; Spieser M.; Yoo W. J.; Taniguchi T.; Watanabe K.; Aruta C.; Ciarrocchi A.; Kis As; Lee B. S.; Lipson M.; Hone J.; Shahrjerdi D.; Riedo E.

Advanced Science Research Center (ASRC), CUNY Graduate Center, New York NY 10031, USA; Tandon School of Engineering, New York University, New York NY 11201, USA ; Dipartimento di Fisica, Politecnico di Milano, Milano 20133, Italy; Department of Mechanical Engineering, Columbia University, New York NY 10027, USA; SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea; SwissLitho AG Technoparkstrasse 1, Zurich CH-8005, Switzerland; National Institute of Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044,Japan; National Research Council (CNR-SPIN), Rome 00133, Italy; Electrical Engineering Institute, and Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland; Department of Electrical Engineering, Columbia University, New York NY 10027, USA

Two-dimensional semiconductors, such as molybdenum disulfide (MoS2), exhibit a variety of properties that could be useful in the development of novel electronic devices. However, nanopatterning metal electrodes on such atomic layers, which is typically achieved using electron beam lithography, is currently problematic, leading to non-ohmic contacts and high Schottky barriers. Here, we show that thermal scanning probe lithography can be used to pattern metal electrodes with high reproducibility, sub-10-nm resolution, and high throughput (10(5) mu m(2) h(-1) per single probe). The approach, which offers simultaneous in situ imaging and patterning, does not require a vacuum, high energy, or charged beams, in contrast to electron beam lithography. Using this technique, we pattern metal electrodes in direct contact with monolayer MoS2 for top-gate and back-gate field-effect transistors. These devices exhibit vanishing Schottky barrier heights (around 0 meV), on/off ratios of 10(10), no hysteresis, and subthreshold swings as low as 64 mV per decade without using negative capacitors or hetero-stacks.

Nature electronics 2 (1), pp. 17–25