Mask-free patterning and selective CVD-growth of 2D-TMDCs semiconductors

Abstract

This work reports on a novel mask-free approach that enables controlled selective growth of molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ) crystalline islands on Si/SiO 2 substrates. In particular, the direct-write patterning technique and chemical vapor deposition method are employed to produce arrays of 2D-TMDCs nanostructures at pre-defined locations on the substrates. It is shown that by adjusting the patterning parameters, composition and concentrations of ink-precursors, and the growth conditions, patterns of MoS 2 and WS 2 nanostructures with controlled geometry can be produced. The prepared 2D-TMDCs materials were analyzed by atomic force microscopy, Raman spectroscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy, all of which indicated to high-quality doublelayer MoS 2 and WS 2 nanostructures. The back-gated field effect transistors were fabricated, and their charge carrier mobility values of 11 cm 2 V −1 s −1 for MoS 2 and 4 cm 2 V −1 s −1 for WS 2 were extracted from the device measurements.

In Situ Measurements of Strain Evolution in Graphene/Boron Nitride Heterostructures Using a Non-Destructive Raman Spectroscopy Approach

“…While visual inspection via optical microscopy and SEM did not show notable changes on the surface of 2D materials, we assume some physisorbed or chemisorbed residuals from the wet transfer process have played a role in the slightly diminished QF values, which imply to the increased disorder and/or defects at the interfaces or on the surface of the assembled heterostructure. It is worth noting that the location of the PET band peak at ~1614 cm −1 has a high intensity and interfered with the G -band peak of the SLGr at ~1600 cm −1 [ 3 ]. Hence, we focused our studies on the 2D band of SLGr on PET and FLBN/SLGr on PET heterostructure samples and tracked the strain evolution using shifts measured in the 2D band in the subsequent experiments described below.…”

“…Two-dimensional (2D) materials, in the form of single-layered material or the building block of hybrid systems, have been explored for energy, catalysis, electronics, and medical applications [ 1 , 2 , 3 , 4 ]. Specifically, the superior properties and performance of van der Waals (vdW) materials have continued to motivate researchers and inspired them to make valuable discoveries advantageous for numerous applications in different fields [ 5 , 6 ].…”

“…For example, the transparency, different electronic band gaps, lightweight, high Young’s modulus, and high strength are some of the most desirable properties of 2D materials for practical and industrial implementations [ 5 , 7 , 8 ], specific to 2D nanostructures compared with their bulk counterparts. These properties make graphene (Gr); boron nitride (BN); and other vdW structures, such as transition metal dichalcogenides (TMDCs), promising materials for potential electronic, optoelectronic, and mechanical applications [ 3 , 7 , 9 , 10 , 11 , 12 ]. Although 2D materials have shown outstanding intrinsic properties, it is essential to understand their potential in terms of durability for long-lasting and reliable applications.…”

Recent Advances in Spin-coating Precursor Mediated Chemical Vapor Deposition of Two-Dimensional Transition Metal Dichalcogenides

“…It is utilized to deposit arrays of patterns on preselected locations via the direct write patterning (DWP) technique. 32 Figure 8c shows the representative images of grown patterned MoS 2 and WS 2 nanoflakes with a domain size of 8−10 μm and a thickness of average 2 nm. As for inkjet printing, it is supposed to be a desirable patterning way.…”

Site-selective growth of two-dimensional materials: strategies and applications

“…8c presents a direct-write patterning technique to grow MoS 2 and WS 2 crystalline islands at defined locations. 112 The precursor inks were made of (NH 4 ) 2 MoS 4 and (NH 4 ) 10 H 2 (W 2 O 7 ) 6 compounds which were diluted in deionized water. Then, the inks were deposited onto the substrates using the direct-writing patterning technique, forming arrays of dots to serve as the nucleation sites to grow MoS 2 and WS 2 islands, respectively.…”