Determining by Raman spectroscopy the average thickness and N-layer-specific surface coverages of MoS₂ thin films with domains much smaller than the laser spot size

• Felipe Wasem Klein,
• Jean-Roch Huntzinger,
• Vincent Astié,
• Damien Voiry,
• Romain Parret,
• Houssine Makhlouf,
• Sandrine Juillaguet,
• Jean-Manuel Decams,
• Sylvie Contreras,
• Périne Landois,
• Ahmed-Azmi Zahab,
• Jean-Louis Sauvajol and
• Matthieu Paillet

Beilstein J. Nanotechnol. 2024, 15, 279–296, doi:10.3762/bjnano.15.26

• Raman spectroscopy is a widely used technique to characterize nanomaterials because of its convenience, non-destructiveness, and sensitivity to materials change. The primary purpose of this work is to determine via Raman spectroscopy the average thickness of MoS2 thin films synthesized by direct liquid

• first reassess the applicability of different Raman criteria to determine the thicknesses (or layer number, N) of MoS2 flakes from measurements performed on reference samples, namely well-characterized mechanically exfoliated or standard chemical vapor deposition MoS2 large flakes deposited on 90 ± 6 nm

• SiO2 on Si substrates. Then, we discuss the applicability of the same criteria for significantly different DLI-PP-CVD MoS2 samples with average thicknesses ranging from sub-monolayer up to three layers. Finally, an original procedure based on the measurement of the intensity of the layer breathing

A visible-light photodetector based on heterojunctions between CuO nanoparticles and ZnO nanorods

• Doan Nhat Giang,
• Nhat Minh Nguyen,
• Duc Anh Ngo,
• Thanh Trang Tran,
• Le Thai Duy,
• Cong Khanh Tran,
• Thi Thanh Van Tran,
• Phan Phuong Ha La and
• Vinh Quang Dang

Beilstein J. Nanotechnol. 2023, 14, 1018–1027, doi:10.3762/bjnano.14.84

• , these methods still face problems, including the requirements of controlling defects, scale-up for mass production, or troubles relating to decoration uniformity [31][32]. Another method is to form heterojunctions of ZnO and other narrow-bandgap semiconductors (NiO [33], PbS [34], CdS [35], and MoS2[36

Nanoarchitectonics of photothermal materials to enhance the sensitivity of lateral flow assays

• Elangovan Sarathkumar,
• Rajasekharan S. Anjana and
• Ramapurath S. Jayasree

Beilstein J. Nanotechnol. 2023, 14, 988–1003, doi:10.3762/bjnano.14.82

• typhimurium bacteria using Prussian blue and a Au composite. The results proved that photothermal signal amplification yielded a much higher sensitivity (101 CFU·mL−1) than the colorimetric method (102 CFU·mL−1) [86]. Before that, the same group developed a MoS2@Au nanocomposite for the photothermal detection

Nanomaterials for photocatalysis and applications in environmental remediation and renewable energy

• Viet Van Pham and
• Wee-Jun Ong

Beilstein J. Nanotechnol. 2023, 14, 722–724, doi:10.3762/bjnano.14.58

• ]. Semiconducting photocatalyst nanomaterials, such as SnO2, TiO2, MoS2, g-C3N4, and Bi-nanostructures have been proven efficient for a range of applications, including organic pollutant removal, NOx degradation, renewable energy production, and waste-to-energy conversion [15][17][18]. Figure 1 shows a general

• with various morphologies demonstrated many preeminent features in the above applications. In detail, the MoS2 with a honeycomb-like structure was first synthesized by an electrochemical route and applied in dye-sensitized solar cells [19], which expressed a higher applicability than that of other

Atmospheric water harvesting using functionalized carbon nanocones

• Fernanda R. Leivas and
• Marcia C. Barbosa

Beilstein J. Nanotechnol. 2023, 14, 1–10, doi:10.3762/bjnano.14.1

• monolayers of graphene and MoS2 [43][44]. Another advantage of the cone format is the possibility of capturing more water at the larger diameter entrance, without losing the high flow at the reduced diameter in other parts of the cone. As the example of the Namibian desert beetle shows, the introduction of

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• efficiency. Through a comparison of MoS2/TNAs and g-C3N4/TNAs, it was found that TNAs modified with MoS2 and g-C3N4 exhibited a current density of, respectively, 210.6 and 139.6 μA·cm−2 at an overpotential of 1.23 V vs RHE, which is 18.2 and 12 times higher than that of pure TNAs under the same conditions

• . The stability of the MoS2/TNAs heterojunction is higher than that of g-C3N4/TNAs. Keywords: band structure; g-C3N4/TiO2; MoS2/TiO2; photoelectrochemical; water splitting; Introduction Hydrogen energy has become a target pursued in the energy development strategies of many countries and regions

• the required amounts of noble metals and materials such as CdS or ZnS [26][27][28][29]. There are many low-bandgap semiconductors that were coupled with TNAs, including MoS2, WS2, MoSe2, g-C3N4, Cu2O, and CuO. MoS2 is a semiconductor with a narrow bandgap (1.9 eV at room temperature) exhibiting unique

Recent trends in Bi-based nanomaterials: challenges, fabrication, enhancement techniques, and environmental applications

• Vishal Dutta,
• Ankush Chauhan,
• Ritesh Verma,
• C. Gopalkrishnan and
• Van-Huy Nguyen

Beilstein J. Nanotechnol. 2022, 13, 1316–1336, doi:10.3762/bjnano.13.109

• , and SrTiO3), sulfates (e.g., MoS2 and Bi2S3), selenides (e.g., MoSe2 and CdSe), and phosphates (e.g., Ag3PO4) [8][9][10][11][12][13][14][15]. The bandgap of photocatalysts sensitive to visible light is smaller than 3 eV. Wide-bandgap photocatalysts can only be stimulated by ultraviolet light, which

• of one semiconductor to the VB of the other in an S-scheme heterojunction photocatalyst due to an IEF that typically exists at the interface of the two semiconductors [104]. Lately, Xu et al. reported the fabrication of a MoS2/BiVO4 heterojunction via solvothermal and electrospinning techniques [105

• ]. Without any additional agent, the fabricated heterojunction completely degraded a RhB dye solution within 20 min. BiVO4 nanorods photogenerated hydroxyl radicals rather than super oxides because of the more positive oxidation potential of BiVO4 (2.31 V). MoS2 sheets favored the photogeneration of

Application of nanoarchitectonics in moist-electric generation

• Jia-Cheng Feng and
• Hong Xia

Beilstein J. Nanotechnol. 2022, 13, 1185–1200, doi:10.3762/bjnano.13.99

• can be easily grown on substrates to form nanoscale networks and perform well in MEGs due to their unique electron transport properties [2][47][48]. This includes Al2O3 [49], MoS2 [50][51], Ni–Al layered double hydroxide (LDH) [52], MoS2/SiO2 composites [53], TiO2 [54], and Ti3C2Tx MXene nanosheets

• . A phase-engineered flexible MoS2 nanosheet generator is worth mentioning. Through annealing at 150 °C, the 1T phase of MoS2 is changed to the 2H phase. The 2H phase can dissociate more water molecules into hydrogen ions than the 1T phase (Figure 4d,e). Thus, the different phases yield a difference

• in hydrogen ion concentration and this difference forms the induced current in the external circuit. The MoS2 film can provide a continuous electrical output of 19 mV and 6.24 μA. The introduction of ion concentration difference is a valuable improvement. This artificially created internal ion

Self-assembly of C₆₀ on a ZnTPP/Fe(001)–p(1 × 1)O substrate: observation of a quasi-freestanding C₆₀ monolayer

• Guglielmo Albani,
• Michele Capra,
• Alessandro Lodesani,
• Alberto Calloni,
• Gianlorenzo Bussetti,
• Marco Finazzi,
• Franco Ciccacci,
• Alberto Brambilla,
• Lamberto Duò and
• Andrea Picone

Beilstein J. Nanotechnol. 2022, 13, 857–864, doi:10.3762/bjnano.13.76

• layer of 2D material, such as graphene [27][28], hexagonal boron nitride [29][30][31] and MoS2 [32][33]. Moreover, an organic layer inserted between the substrate and the overlayer has been shown to be effective in improving the order of the molecular film [34][35] or restoring its original electronic

Revealing local structural properties of an atomically thin MoSe₂ surface using optical microscopy

• Lin Pan,
• Peng Miao,
• Anke Horneber,
• Alfred J. Meixner,
• Pierre-Michel Adam and
• Dai Zhang

Beilstein J. Nanotechnol. 2022, 13, 572–581, doi:10.3762/bjnano.13.49

• photoluminescence spectroscopy. Owing to the larger population of charge carriers, the photoluminescence from these structural defects of monolayer WS2 originates from the biexcitons under high-power excitation [16]. Interestingly, tilt boundaries in monolayer MoS2 induce strong photoluminescence enhancement and

• defect-induced band bending of the conduction band at K and Q states in few-layer MoS2 [9][10]. All in all, structural irregularities play a crucial role in the modification of the electron band structure in 2D-TMDCs, further ruling their optical and electronic properties. Therefore, the relationship

• , including graphene and 2D-TMDC materials, are unique platforms for SERS investigations based on the chemical mechanism [21]. Recently, enhanced Raman signals of rhodamine 6G (R6G) molecules on an oxygen plasma-treated MoS2 flake were reported, because the symmetry of the R6G molecule can be modified through

Influence of thickness and morphology of MoS₂ on the performance of counter electrodes in dye-sensitized solar cells

• Lam Thuy Thi Mai,
• Hai Viet Le,
• Ngan Kim Thi Nguyen,
• Van La Tran Pham,
• Thu Anh Thi Nguyen,
• Nguyen Thanh Le Huynh and
• Hoang Thai Nguyen

Beilstein J. Nanotechnol. 2022, 13, 528–537, doi:10.3762/bjnano.13.44

• disulfide (MoS2) was prepared on substrates coated with fluorine-doped tin oxide (FTO) to substitute the platinum counter electrode (CE) for dye-sensitized solar cells (DSSCs). Herein, we synthesized layered and honeycomb-like MoS2 thin films via the cyclic voltammetry (CV) route. Thickness and morphology

• of the MoS2 thin films were controlled via the concentration of precursor solution. The obtained results showed that MoS2 thin films formed at a low precursor concentration had a layered morphology while a honeycomb-like MoS2 thin film was formed at a high precursor concentration. Both types of MoS2

• thin film were composed of 1T and 2H structures and exhibited excellent electrocatalytic activity for the I3–/I− redox couple. DSSCs assembled using these MoS2 CEs showed a maximal power conversion efficiency of 7.33%. The short-circuit value reached 16.3 mA·cm−2, which was higher than that of a

Electrostatic pull-in application in flexible devices: A review

• Teng Cai,
• Yuming Fang,
• Yingli Fang,
• Ruozhou Li,
• Ying Yu and
• Mingyang Huang

Beilstein J. Nanotechnol. 2022, 13, 390–403, doi:10.3762/bjnano.13.32

• CVD for analog and digital bandwidth phase shifters. The phase shift was 355°/dB in the analog design at 2.4 GHz and 138°/dB in the digital design. Anjum et al. [60] used GR/MoS2 composite materials as beam to decrease the pull-in voltage below 1 V, which can be used in RF applications requiring low

Theoretical understanding of electronic and mechanical properties of 1T′ transition metal dichalcogenide crystals

• Seyedeh Alieh Kazemi,
• Sadegh Imani Yengejeh,
• Vei Wang,
• William Wen and
• Yun Wang

Beilstein J. Nanotechnol. 2022, 13, 160–171, doi:10.3762/bjnano.13.11

• comparatively weak van der Waals (vdW) interactions [7]. The most extensively studied TMDs, including MoS2, MoSe2, WS2, and WSe2, can display different structural polytypes (e.g., 2H, 3R, 1T, and 1T′) [8]. Previous studies have revealed that the structures significantly affected the properties and physical

• ability to predict the mechanical characteristics of 1T′ TMD materials [33]. In this comparative study, the electronic and mechanical properties including shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (ν), and microhardness (H), of MoS2, MoSe2, WS2, and WSe2 crystals with the

• to the reported electronic properties of TMDs. However, there are still some subtle differences between the pDOS graphs. It can be found that the MoS2 and WS2 have relatively strong peaks at the E − EFermi range between −4 and −3 eV. As a comparison, the DOS of diselenides in the range between −2 and

Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review

• Keshav Nagpal,
• Erwan Rauwel,
• Frédérique Ducroquet and
• Protima Rauwel

Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80

• . obtained an optimum concentration of 0.03 wt % of graphene in PEDOT:PSS [65]. A combination of MoS2 and graphene sheets has also displayed good HIL tendencies due to the high surface coverage, work function, and low LUMO levels of graphene [66]. With regards to SPR of MNP, green emission enhancement in

• (Figure 7) present the best results in terms of luminance and EL emission. In addition, the electron conductivity of the device is increased by four orders of magnitude. Concerning graphene–polymer nanocomposites, Choudhary et al. have inserted MoS2 and graphene oxide NP into a polyaniline ETL [72]. The

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• substrate and the organic building blocks. Recently, two-dimensional (2D) materials, including hexagonal boron nitride (hBN) [22][23], graphene [24][25][26][27], and MoS2 [28], have emerged as monatomically thin decoupling layers. Van der Waals 2D materials are generally well suited due to their chemical

• . The significantly reduced resonance width allowed for resolving vibronic states in both frontier orbitals on graphene/Pt(111) by STS. The semiconducting 2D material MoS2 may act as a decoupling layer for molecules from the underlying metal substrate if the molecular resonances lie within the MoS2

• bandgap. Hence, Yousofnejad et al. [85] found using MoS2 on Ag(111) as substrate that the HOMO of tetracyanoquinodimethane (TNCQ) is not decoupled because it is located in the MoS2 valence band, while the lowest unoccupied molecular orbital narrows but still suffers from lifetime broadening because it is

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• crystals (van der Waals heterostructures, graphene, hBN, MoS2, and WTe2) was demonstrated. The detection algorithm enables real-time detection of the 2D materials (running for 200 ms on a 1024 × 1024 optical image) and is insensitive to variations in microscopy conditions such as illumination and color

Prediction of Co and Ru nanocluster morphology on 2D MoS₂ from interaction energies

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2021, 12, 704–724, doi:10.3762/bjnano.12.56

• Cara-Lena Nies Michael Nolan Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork, T12 R5CP, Ireland NIBEC, School of Engineering, University of Ulster at Jordanstown BT37 0QB, United Kingdom 10.3762/bjnano.12.56 Abstract Layered materials, such as MoS2, have a

• interaction between metals and the MoS2 monolayer is of great importance when selecting systems for specific applications. In previous studies the focus has been largely on the strength of the interaction between a single atom or a nanoparticle of a range of metals, which has created a significant knowledge

• gap in understanding thin film nucleation on 2D materials. In this paper, we present a density functional theory (DFT) study of the adsorption of small Co and Ru structures, with up to four atoms, on a monolayer of MoS2. We explore how the metal–substrate and metal–metal interactions contribute to the

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• ]. Various 2D transition metal dichalcogenides have also been the subject of conductivity-tuning studies in the HIM. For example, Fox et al. showed that site-selective helium ion irradiation, introducing point defects and local disorder, transformed targeted regions of a supported pristine few-layer MoS2

• formation of extended metallic edge states in the defective lattice was proposed for the pseudometallic regime [26]. Line irradiation with helium ions bisecting a monolayer MoS2 flake has been shown to create a defective channel that can be used to fabricate a 2D memristive device [27]. And in a subsequent

• study, field-effect transistors based on monolayer MoS2 were irradiated with helium ions over the transistor channel and the effect of varying the size and position of the irradiated area on the electrical performance of the device was characterized [28]. Complimentary work on few-layer WSe2 by Stanford

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• for graphene and MoS2-based electronics utilising the small lattice mismatch, the large optical phonon modes, and particularly the large bandgap [3][4][5][6][7][8][9][10]. Furthermore, when grown on metal substrates h-BN can be used as a nanoscale template for atoms, molecules, and nanostructures with

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

• Reimer Karstens,
• Thomas Chassé and
• Heiko Peisert

Beilstein J. Nanotechnol. 2021, 12, 485–496, doi:10.3762/bjnano.12.39

• properties. Hence, TMPcs are well suited for systematic studies of interface properties. The fluorination of TMPcs varies exceptionally the ionization potential (IP), affecting distinctly the interface properties [29][30][31][32]. As recently shown for FePcFx/MoS2 [33], a charge transfer at interfaces might

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• molecular wetting layers [15] and two-dimensional materials, such as graphene [16][17], hBN [11][18], or even organic layers [19]. Recently, it has been proposed that a monolayer of transition metal dichalcogenides, for example, MoS2, may play a similar role [4][20][21]. Similarly, it has been reported that

Nanomechanics of few-layer materials: do individual layers slide upon folding?

• Ronaldo J. C. Batista,
• Rafael F. Dias,
• Ana P. M. Barboza,
• Alan B. de Oliveira,
• Taise M. Manhabosco,
• Thiago R. Gomes-Silva,
• Matheus J. S. Matos,
• Andreij C. Gadelha,
• Cassiano Rabelo,
• Luiz G. L. Cançado,
• Ado Jorio,
• Hélio Chacham and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2020, 11, 1801–1808, doi:10.3762/bjnano.11.162

• layered materials as it determines the interlayer slip, which is the dominant mechanism to relieve stress at van der Waals interfaces, leading to phenomena such as the change from plate-like to membrane-like shapes in graphene, hBN, and MoS2 bubbles [12] or the circumferential faceting of multi-walled

Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS₂ field-effect transistors

• Jakub Jadwiszczak,
• Pierce Maguire,
• Conor P. Cullen,
• Georg S. Duesberg and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2020, 11, 1329–1335, doi:10.3762/bjnano.11.117

• study of the electrical performance of chemically synthesized monolayer molybdenum disulfide (MoS2) field-effect transistors irradiated with a focused helium ion beam as a function of increasing areal irradiation coverage. We determine an optimal coverage range of approx. 10%, which allows for the

• improvement of both the carrier mobility in the transistor channel and the electrical conductance of the MoS2, due to doping with ion beam-created sulfur vacancies. Larger areal irradiations introduce a higher concentration of scattering centers, hampering the electrical performance of the device. In addition

• materials; Introduction Layered two-dimensional (2D) semiconductors have come to the fore in recent years as promising candidates for the implementation of flexible, transparent, and low-power electronics. In particular, transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), have

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• in Ca-intercalated bilayer graphene) [5]. Also, this value is higher than that of other superconducting low-dimensional structures, e.g., TC ≈ 20 K for a Li- and Na-intercalated blue phosphorene bilayer [47], TC ≈ 16.5 K for a Li-intercalated black phosphorene bilayer [48], and TC≈ 10 K for a Li–MoS2

• ∈ {14.01, 8.64, 4.6} K, for μ* ∈ {0.1, 0.2, 0.3}, respectively. To realize how uncommonly high the value of λωD/εF for Li-hBN is, it is enough to note that for the Li–MoS2 bilayer, we obtain λωD/εF = 0.15 [49]. In bilayers of black and blue phosphorus intercalated with lithium, λωD/εF is equal to 0.05 and

• }, respectively, for μ* ∈ {0.1, 0.14, 0.2}. This means that the effects considered are significant even when we consider the vertex corrections for the electron–phonon interaction. Also note that retardation and strong-coupling effects for Li-hBN are of the same order as in Li-MoS2 bilayer compounds [49], Li

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• , which is assigned to vibronic progression induced by a single group of molecular vibrations with similar quantum energies. Another type of two-dimensional materials is represented by single layers of transition metal dichalcogenides. A single layer of MoS2 on Au(111) has recently been used to