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Electronic and structural properties are studied at room temperature, whereas the magnetic performances of MoS2-nanoparticles (MoS2-NPs) are studied from room temperature (300 K) down to 5 K within the range of the magnetic field − 10 T to + 10 T. We find that MoS2-NPs display diamagnetic in the temperature range 300–50 K, whereas at ≈ 45 K the M–H hysteresis curve shows the presence of both diamagnetic and ferromagnetic behaviours. The existence of ferromagnetism is significantly enhanced from 40 K down to 5 K, presumably due to Mo-atom, S-vacancies/O-vacancies, defective structure due to the higher density of dangling bonds, and small MoS2-NPs sizes. Different ferromagnetic parameters viz. saturation magnetization, retentivity, and coercivity of MoS2-NP at ≈ 5 K are 55 m emu/g, 45 m emu/g, and 4500 Oe respectively are obtained from the M–H hysteresis curve. The electronic, microstructures and defects are also studied using XPS/UPS and Raman spectrum that correlated/consistence with the magnetic performances of MoS2-NPs. This low temperature (≤ 40 K) ferromagnetism in MoS2-NPs could be useful for low temperature promising potential technological magnetic applications. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) study show that the SnO2 and SnO2:F are Sn2+ dominated in the formation of SnO2 structure. The SnO2:F thin film is mainly the formation of metallic fluoride. The UPS study confirms the density of states of SnO2:F is higher than SnO2. The work function, valence band maximum and surface potentials of SnO2 (SnO2:F) are estimated from UPS spectra and are 3.9 eV (3.7 eV), 3.7 V (3.5 eV) and 7.6 eV (7.2 eV), respectively. Electrical conductivity and M–H hysteresis loop show SnO2:F have higher conductivity as well as magnetization. [ABSTRACT FROM AUTHOR]

Highlights • Metallic octahedral prismatic 1T- and trigonal prismatic bulk crystal 2H-phase MoS 2. • The work functions are ∼3.5 eV and ∼3.3 eV for 1T- and 2H-phase MoS 2 respectively. • Photoluminescence intensity gradually decrease with synthesized temperature. Abstract Molybdenum di-sulfide thin films of thickness <1500 Å, were prepared by the dip-coating technique at different baking temperatures within the range 400 °C–450 °C using methanolic solution of ammonium molybdate and ammonium thiocyanate and hence studied their different properties using X-ray diffraction (XRD), UV-vis spectroscopy, Photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and Current-Voltage (I-V) relationship measurements. XRD result shows that the MoS 2 films are mixed metallic octahedral prismatic 1T- and trigonal prismatic bulk crystal 2H-phases. The I-V relationships show higher electrical conductivity for the films prepared at 400 °C and 450 °C than the films prepared at 425 °C. XPS measurement also shows the formation of mixed phases of MoS 2 thin films as revealed by XRD. We have estimated the valence band maximum (VBM) and work functions from higher and lower energy range of UPS (He-I) spectra of MoS 2 thin films prepared at 425 °C and 450 °C. The VBM are ∼4.4 eV & ∼4.2 eV and their work functions are ∼3.5 eV & ∼3.3 eV respectively that are correlated with conductivity and formation of mixed phases of MoS 2 thin films. [ABSTRACT FROM AUTHOR]

• Magnetic behavior of MoS 2 -SC, MoS 2 -NP and 2D bi-layer-MoS 2 thin films. • M−H hysteresis loops measured at 300 K. • Room temperature ferromagnetism in 2D bi-layer-MoS 2. • MoS 2 -SC/MoS 2 -NP shows diamagnetism/paramagnetic. Comparisons of magnetic behavior of pristine single crystal-MoS 2 (MoS 2 -SC), nanoparticle-MoS 2 (MoS 2 -NP) and two-dimensional (2D) bi-layer-MoS 2 thin film were investigated by the M−H hysteresis loops measured at 300 K, using the superconducting quantum interface device-type magnetometer. Results clearly shows that the room temperature ferromagnetism in 2D bi-layer-MoS 2 with saturation of magnetization ∼ 10 × 10-4 emu/g, whereas pristine MoS 2 -SC / MoS 2 -NP shows diamagnetism/paramagnetic behaviour. The X-ray photoelectron and Raman spectroscopy results confirms the observed ferro-magnetization in 2D bi-layer-MoS 2 is related to the presence of edge spins on the edges of layers, S-vacancies (defects at the grain boundaries region) and higher density of states. This 2D bi-layer-MoS 2 may find applications in nanodevices and spintronics by controlling the edge structures. [ABSTRACT FROM AUTHOR]

Abstract With reference of our previous report (Appl. Surf. Sci. 474(2019)227), the molybdenum disulphide (MoS 2) thin film were prepared by the dip-coating technique at different temperatures (400 °C–450 °C) using methanolic solution of ammonium molybdate and ammonium thiocyanate that are used as bare-substrate for the deposition of graphene oxide (GO) thin films. For the deposition of graphene oxide (GO), commercially purchased GO (0.5 mg in 10 mL aqueous solution) was deposited by dip-coating technique on dip-deposited MoS 2 thin film to make layer-by-layer MoS 2 :GO composite thin films and hence studied their electronic and electrical behaviours. The micro-structural and surface morphology were studied using Raman spectroscopy, X-ray diffraction (XRD) and field emission scanning electron microscopy, whereas optical band estimated from the optical absorption spectra. The electronic structure and their bonding properties were studied using X-ray photoelectron spectroscopy and the electrical behaviours were observed from the current-voltage (I-V) characteristic curve. The formation of different phases of MoS:GO thin films show an enhanced electronic and electrical performance due to their unique-structure and the synergetic effect of MoS 2 :GO nanosheets when compared to those of bare MoS 2. Highlights • Layer-by-layer MoS 2 :GO composites nano-structure thin films • Slow nucleation of MoS 2 and GO to form different phases of MoS 2 :GO thin films • Reduction of optical band gap, enhancement of electronic/electrical performances [ABSTRACT FROM AUTHOR]

Abstract: Microstructural properties of ultrathin (1–10nm) tetrahedral amorphous carbon (ta-C) films are investigated by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, X-ray Photoelectron Spectroscopy, Raman spectroscopy and Atomic Force Microscopy (AFM). The CK-edge NEXAFS spectra of 1nm ta-C films provided evidence of surface defects (C―H bonds) which rapidly diminish with increasing film thickness. A critical thickness for stabilization of largely sp3 matrix structure distorted by sp2 sites is observed via the change of π*C═C peak behavior. Meanwhile, an increase in the film thickness promotes an enhancement in sp3 content, the film roughness remains nearly constant as probed by spectroscopic techniques and AFM, respectively. The effect of thickness on local bonding states of ultrathin ta-C films proves to be the limiting factor for their potential use in magnetic and optical storage devices. [Copyright &y& Elsevier]