Gate-Controlled Large Resistance Switching Driven by Charge-Density Wave in 1T-TaS2/2H-MoS2 Heterojunctions

Mahajan, Mehak and Murali, Krishna and Kawatra, Nikhil and Majumdar, Kausik (2019) Gate-Controlled Large Resistance Switching Driven by Charge-Density Wave in 1T-TaS2/2H-MoS2 Heterojunctions. In: PHYSICAL REVIEW APPLIED, 11 (2).

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Abstract

1T-TaS2 is a layered material that exhibits charge density wave (CDW) -induced distinct electrical resistivity phases and has attracted a lot of attention for interesting device applications. However, such resistivity switching effects are often weak, and cannot be modulated by an external gate voltage - limiting their widespread usage. Using a back-gated 1T-TaS2/2H-MoS2 heterojunction, we show that the usual resistivity switching in TaS2 due to different phase transitions is accompanied with a surprisingly strong modulation in the Schottky barrier height (SBH) at the TaS2/MoS2 interface - providing an additional knob to control the degree of the phase-transition-driven resistivity switching by an external gate voltage. In particular, the commensurate (C) to triclinic (T) phase transition results in an increase in the SBH owing to a collapse of the Mott gap in TaS2. The change in SBH allows us to estimate an electrical Mott-gap opening of approximately 71 +/- 7 meV in the C phase of TaS2. On the other hand, the nearly commensurate (NC) to incommensurate (IC) phase transition results in a suppression in the SBH, and the heterojunction shows a gate-controlled resistivity switching ratio up to 17.3, which is approximately 14.5 times higher than that of stand-alone TaS2. The findings mark an important step forward showing a promising pathway to externally control as well as amplify the CDW-induced resistivity switching. This will boost device applications that exploit these phase transitions, such as ultra-broadband photodetection, negative differential conductance, fast oscillator and threshold switching in neuromorphic circuits.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW APPLIED
Publisher:	AMER PHYSICAL SOC
Additional Information:	Copyright of this article belongs to AMER PHYSICAL SOC
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	23 Feb 2019 08:39
Last Modified:	23 Feb 2019 08:39
URI:	http://eprints.iisc.ac.in/id/eprint/61810

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