Study on the Growth Parameters and the Electrical and Optical Behaviors of 2D Tungsten Disulfide.

Author(s) Singh, V.K.; Pendurthi, R.; Nasr, J.R.; Mamgain, H.; Tiwari, R.Shyam; Das, S.; Srivastava, A.
Journal ACS Appl Mater Interfaces
Date Published 2020 Apr 08

Transition-metal dichalcogenides (TMDCs) with atomic thickness are promising materials for next-generation electronic and optoelectronic devices. Herein, we report uniform growth of triangular-shaped (∼40 μm) monolayer WS using the atmospheric-pressure chemical vapor deposition (APCVD) technique in a hydrogen-free environment. We have studied the optical and electrical behaviors of as-grown WS samples. The absorption spectrum of monolayer WS shows two intense excitonic absorption peaks, namely, A (∼630 nm) and B (∼530 nm), due to the direct gap transitions at the K point. Photoluminescence (PL) and fluorescence studies reveal that under the exposure of green light, monolayer WS gives very strong red emission at ∼663 nm. This corresponds to the direct band gap and strong excitonic effect in monolayer WS. Furthermore, the efficacy of the synthesized WS crystals for electronic devices is also checked by fabricating field-effect transistors (FETs). FET devices exhibit an electron mobility of μ ∼ 6 cm V s, current ON/OFF ratio of ∼10, and subthreshold swing (SS) of ∼641 mV decade, which are comparable to those of the exfoliated monolayer WS FETs. These findings suggest that our APCVD-grown WS has the potential to be used for next-generation nanoelectronic and optoelectronic applications.

DOI 10.1021/acsami.9b19820
ISSN 1944-8252
Citation ACS Appl Mater Interfaces. 2020;12(14):1657616583.

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