Formation of Highly Conductive Interfaces in Crystalline Ionic Liquid-Gated Unipolar MoTe2/h-BN Field-Effect Transistor

Kamoladdin Saidov; Jamoliddin Razzokov; Odilkhuja Parpiev; Nur Sena Yüzbasi; Natalia Kovalska; Gurdial Blugan; Olim Ruzimuradov

doi:10.3390/nano13182559

Formation of Highly Conductive Interfaces in Crystalline Ionic Liquid-Gated Unipolar MoTe₂/h-BN Field-Effect Transistor

Nanomaterials (Basel). 2023 Sep 15;13(18):2559. doi: 10.3390/nano13182559.

Authors

Kamoladdin Saidov^{1

2

3}, Jamoliddin Razzokov^{4

5

6}, Odilkhuja Parpiev⁷, Nur Sena Yüzbasi⁸, Natalia Kovalska⁸, Gurdial Blugan⁸, Olim Ruzimuradov⁹

Affiliations

¹ Department of Electronics and Radio Engineering, Tashkent University of Information Technologies, Tashkent 100200, Uzbekistan.
² Department of Information Technologies, Tashkent International University of Education, Tashkent 100207, Uzbekistan.
³ Department of Electrical and Computer Engineering, Ajou University in Tashkent, Tashkent 100204, Uzbekistan.
⁴ R&D Center, New Uzbekistan University, Tashkent 100007, Uzbekistan.
⁵ School of Engineering, Central Asian University, Tashkent 111221, Uzbekistan.
⁶ Institute of Fundamental and Applied Research, National Research University TIIAME, Tashkent 100000, Uzbekistan.
⁷ Material Sciences Institute, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100084, Uzbekistan.
⁸ Laboratory for High Performance Ceramics, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
⁹ Department of Natural and Mathematic Sciences, Turin Polytechnic University in Tashkent, Tashkent 100095, Uzbekistan.

Abstract

2H MoTe₂ (molybdenum ditelluride) has generated significant interest because of its superconducting, nonvolatile memory, and semiconducting of new materials, and it has a large range of electrical properties. The combination of transition metal dichalcogenides (TMDCs) and two dimensional (2D) materials like hexagonal boron nitride (h-BN) in lateral heterostructures offers a unique platform for designing and engineering novel electronic devices. We report the fabrication of highly conductive interfaces in crystalline ionic liquid-gated (ILG) field-effect transistors (FETs) consisting of a few layers of MoTe₂/h-BN heterojunctions. In our initial exploration of tellurium-based semiconducting TMDs, we directed our attention to MoTe₂ crystals with thicknesses exceeding 12 nm. Our primary focus centered on investigating the transport characteristics and quantitatively assessing the surface interface heterostructure. Our transconductance (g_m) measurements indicate that the very efficient carrier modulation with an ILG FET is two times larger than standard back gating, and it demonstrates unipolarity of the device. The ILG FET exhibited highly unipolar p-type behavior with a high on/off ratio, and it significantly increased the mobility in MoTe₂/h-BN heterochannels, achieving improvement as one of the highest recorded mobility increments. Specifically, we observed hole and electron mobility values ranging from 345 cm² V^-1 s^-1 to 285 cm² V^-1 s^-1 at 80 K. We predict that our ability to observe the intrinsic, heterointerface conduction in the channels was due to a drastic reduction of the Schottky barriers, and electrostatic gating is suggested as a method for controlling the phase transitions in the few layers of TMDC FETs. Moreover, the simultaneous structural phase transitions throughout the sample, achieved through electrostatic doping control, presents new opportunities for developing phase change devices using atomically thin membranes.

Keywords: MoTe2/h-BN field-effect transistor; charge transfer; ionic-liquid gating; transconductance.

Grants and funding

This study was supported by the Innovative Development Agency under the Ministry of higher education, science and innovation of the Republic of Uzbekistan within Research Project No. FZ-2020092325 and Project No MRB-2021-538.