Percolative switching in transition metal dichalcogenide field-effect transistors at room temperature

Paul, Tathagata and Ghatak, Subhamoy and Ghosh, Arindam (2016) Percolative switching in transition metal dichalcogenide field-effect transistors at room temperature. In: NANOTECHNOLOGY, 27 (12).

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Abstract

We have addressed the microscopic transport mechanism at the switching or `on-off' transition in transition metal dichalcogenide (TMDC) field-effect transistors (FETs), which has been a controversial topic in TMDC electronics, especially at room temperature. With simultaneous measurement of channel conductivity and its slow time-dependent fluctuation (or noise) in ultrathin WSe2 and MoS2 FETs on insulating SiO2 substrates where noise arises from McWhorter-type carrier number fluctuations, we establish that the switching in conventional backgated TMDC FETs is a classical percolation transition in a medium of inhomogeneous carrier density distribution. From the experimentally observed exponents in the scaling of noise magnitude with conductivity, we observe unambiguous signatures of percolation in a random resistor network, particularly, in WSe2 FETs close to switching, which crosses over to continuum percolation at a higher doping level. We demonstrate a powerful experimental probe to the microscopic nature of near-threshold electrical transport in TMDC FETs, irrespective of the material detail, device geometry, or carrier mobility, which can be extended to other classes of 2D material-based devices as well.

Item Type:	Journal Article
Publication:	NANOTECHNOLOGY
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	percolative transport; 1/f noise; TMDC FET
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 Apr 2016 10:54
Last Modified:	02 Apr 2016 10:54
URI:	http://eprints.iisc.ac.in/id/eprint/53446

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