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Combinatorial large-area MoS2/anatase−TiO2 interface: A pathway to emergent optical and optoelectronic functionalities

Maji, TK and Aswin, JR and Mukherjee, S and Alexander, R and Mondal, A and Das, S and Sharma, RK and Chakraborty, NK and Dasgupta, K and Sharma, AMR and Hawaldar, R and Pandey, M and Naik, A and Majumdar, K and Pal, SK and Adarsh, KV and Ray, SK and Karmakar, D (2020) Combinatorial large-area MoS2/anatase−TiO2 interface: A pathway to emergent optical and optoelectronic functionalities. In: ACS Applied Materials and Interfaces, 12 (39). pp. 44345-44359.

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Official URL: https://doi.org/10.1021/acsami.0c13342


The interface of transition-metal dichalcogenides (TMDCs) and high-k dielectric transition-metal oxides (TMOs) had triggered umpteen discourses because of the indubitable impact of TMOs in reducing the contact resistances and restraining the Fermi-level pinning for the metal−TMDC contacts. In the present work, we focus on the unresolved tumults of large-area TMDC/TMO interfaces, grown by adopting different techniques. Here, on a pulsed laser-deposited MoS2 thin film, a layer of TiO2 is grown by atomic layer deposition (ALD) and pulsed laser deposition (PLD). These two different techniques emanate the layer of TiO2 with different crystallinities, thicknesses, and interfacial morphologies, subsequently influencing the electronic and optical properties of the interfaces. Contrasting the earlier reports of n-type doping at the exfoliated MoS2/TiO2 interfaces, the large-area MoS2/anatase−TiO2 films had realized a p-type doping of the underneath MoS2, manifesting a boost in the extent of p-type doping with increasing thickness of TiO2, as emerged from the X-ray photoelectron spectra. Density functional analysis of the MoS2/anatase−TiO2 interfaces, with pristine and interfacial defect configurations, could correlate the interdependence of doping and the terminating atomic surface of TiO2 on MoS2. The optical properties of the interface, encompassing photoluminescence, transient absorption and z-scan two-photon absorption, indicate the presence of defect-induced localized midgap levels in MoS2/TiO2 (PLD) and a relatively defect-free interface in MoS2/ TiO2 (ALD), corroborating nicely with the corresponding theoretical analysis. From the investigation of optical properties, we indicate that the MoS2/TiO2 (PLD) interface may act as a promising saturable absorber, having a significant nonlinear response for the sub-band-gap excitations. Moreover, the MoS2/TiO2 (PLD) interface had exemplified better phototransport properties. A potential application of MoS2/TiO2 (PLD) is demonstrated by the fabrication of a p-type phototransistor with the ionic-gel top gate. This endeavor to analyze and perceive the MoS2/TiO2 interface establishes the prospectives of large-area interfaces in the field of optics and optoelectronics. © 2020 American Chemical Society

Item Type: Journal Article
Publication: ACS Applied Materials and Interfaces
Publisher: American Chemical Society
Additional Information: The copyright for this article belongs to American Chemical Society.
Keywords: Atom lasers; Atomic layer deposition; Energy gap; High-k dielectric; Layered semiconductors; Metal analysis; Optical properties; Oxide minerals; Photoelectron spectroscopy; Photons; Pulsed laser deposition; Pulsed lasers; Saturable absorbers; Semiconductor doping; Semiconductor quantum wells; Titanium dioxide; Transition metal oxides; Transition metals; Two photon processes, Density functionals; Electronic and optical properties; Interfacial morphologies; Non-linear response; Transient absorption; Transition metal dichalcogenides; Two photon absorption; X ray photoelectron spectra, Molybdenum compounds
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering > Electrical Communication Engineering - Technical Reports
Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited: 12 Jan 2023 11:05
Last Modified: 12 Jan 2023 11:05
URI: https://eprints.iisc.ac.in/id/eprint/79067

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