Mechanical properties of RF-sputtering MoS₂thin films

Abstract

We present an evaluation of the hardness and Young's modulus properties of medium pressure sputtered molybdenum disulfide (MoS 2 ) thin films by applying nano-indentation with continuous stiffness method combined with microstructure analysis using small angle x-ray diffraction, Raman, and an electron microscope in scanning and transmission mode. Our results indicate a vertical growth of MoS 2 crystallites with stacking values of 7-laminates along the [0 0 1] direction and an average height of 105 nm, principal Raman vibrations at E 2g 1 at 378 cm −1 and A 1g at 407 cm −1 and an interplanar distance of ~0.62 nm as confirmed by high-resolution transmission electron microscopy. An average hardness of H = 10.5 ± 0.1 GPa and elastic modulus of E = 136 ± 2 GPa from 0 to 90 nm of indenter penetration were found in these investigations.

Study of indium tin oxide—MoS2 interface by atom probe tomography

“…Amorphization is typical, mainly in semiconductors as extensively described by Bogdanowicz et al for silicon (Si) and gallium nitride (GaN) thin films during the FIB lift-out process. [20] Vertical nucleation and growth oriented along the 〈110〉-MoS 2 direction of neddle-like crystallites over the silicon substrate using similar RF-sputtering conditions have been previously reported by Ramos et al, [21] and it is presented in Figs. 1(a) [22] ; (c) SEM image for the MoS 2 surface; it is possible to observe vertical laminar structures typical of MoS 2 (inset: colored signals of the Mo and S content as obtained by EDS), in agreement with Lince and Fleischauer [22] ; and (d) energy-dispersive x-ray spectroscopy (EDS) taken from MoS 2 surfaces during the SEM survey (inset: an enlarge region near 2.1 keV where S-KA1 and Mo-LA1 signals overlap).…”

On the Electronic Structure of 2H-MoS2: Correlating DFT Calculations and In-Situ Mechanical Bending on TEM

“…Beyond conventional electron microscopy, nowadays in-situ techniques have attracted much attention, especially for the evaluation during observations of fundamental aspects such as mechanical strength using TEM sample holders adapted with AFM nanoindenters [ 18 , 19 ]. Previous nano-indenter measurements indicate that 2H-MoS 2 thin films have an average hardness of 10.5 ± 0.1 GPa and elastic modulus of 136 ± 2 GPa [ 20 ], similar to studies completed by Lahouij et al on onion-like MoS 2 nanoparticles, which demonstrate strong evidence of tribological properties for normal forces of 100 nN and 400 nN with an experimental values contact pressure of 20 MPa to 90 MPa [ 21 ]. Here, we present a systematic study on the bending behavior of a 2H-MoS 2 slab in the <001> direction employing density functional calculations.…”

The electronic states of ITO–MoS2: Experiment and theory

“…1(b)). MoS 2 deposited under the mentioned conditions tends to have needle-like crystallites nucleated along the < 110 > direction [17] as observed by scanning electron microscopy characterization (Fig. S2a).…”

“…Once a layer of ITO is created the coupon was baked at 300°C for 20 min to achieve an ohmic contact material at atmospheric pressure using a 100 standard cm 3 /min gas flow mixture of 3.8% H 2 /Balance N 2 ; next, one layer of approximately 700 nm of MoS 2 was deposited in 3600 s as described in prior authors works. [16,17] Atom probe tomography (APT)…”