Tailoring the electrical and photo-electrical properties of a WS2 field effect transistor by selective n-type chemical doping

Muhammad Waqas Iqbal; Muhammad Zahir Iqbal; Muhammad Farooq Khan; Muhammad Arshad Kamran; Abdul Majid; Thamer Alharbi; Jonghwa Eom

doi:10.1039/C6RA02390H

Tailoring the electrical and photo-electrical properties of a WS₂ field effect transistor by selective n-type chemical doping†

Muhammad Waqas Iqbal,*^a Muhammad Zahir Iqbal,^cd Muhammad Farooq Khan,^b Muhammad Arshad Kamran,^a Abdul Majid,^a Thamer Alharbi^a and Jonghwa Eom^b

Author affiliations

* Corresponding authors

^a Department of Physics, College of Science, Majmaah University, Al-Zulfi 11932, Saudi Arabia
E-mail: mw.iqbal@mu.edu.sa

^b Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747, Korea

^c Department of Physics & Astronomy, Georgia State University, Atlanta, Georgia 30303, USA

^d Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Pakistan

Abstract

Here, we demonstrate a doping technique which remarkably improves the electrical and photoelectric characteristics of a WS₂ field effect transistor (FET) by chemical doping. The shift of the threshold voltage towards a negative gate voltage and the red shift of the E¹_2g and A_1g peaks in the Raman spectra confirm the n-type doping effect in WS₂ FETs. WS₂ films show an unprecedented high mobility of 255 cm² V⁻¹ s⁻¹ at room temperature. The on/off ratio of the output current is ∼10⁸ at room temperature. The mobility of a multilayer ML-WS₂ FET was found to be 425 cm² V⁻¹ s⁻¹ at 5 K. Semiconductor-to-metal transitions were also observed at V_bg > 30 V. A decrease in contact and sheet resistance was observed after potassium iodide (KI) doping. The photocurrent in WS₂ FETs was also enhanced after n-type doping. Chemical doping exhibited a very stable, effective, and easy-to-apply method to enhance the performance of a WS₂ FET.

This article is part of the themed collection: 2D Materials: Explorations Beyond Graphene

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Article information

DOI: https://doi.org/10.1039/C6RA02390H
Article type: Paper
Submitted: 26 Jan 2016
Accepted: 25 Feb 2016
First published: 26 Feb 2016

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RSC Adv., 2016,6, 24675-24682

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Tailoring the electrical and photo-electrical properties of a WS₂ field effect transistor by selective n-type chemical doping

M. W. Iqbal, M. Z. Iqbal, M. F. Khan, M. A. Kamran, A. Majid, T. Alharbi and J. Eom, RSC Adv., 2016, 6, 24675 DOI: 10.1039/C6RA02390H

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