In Situ Ultrafast and Patterned Growth of Transition Metal Dichalcogenides from Inkjet‐Printed Aqueous Precursors

Abstract

TMDCs, [7][8][9] the quantum spin Hall effect, [10] the valleytronics, [11,12] as well as the 2D superconductivity, [13] implying extensive potential applications. In contrast to graphene, monolayer TMDCs with suitable bandgaps have demonstrated the state-of-the-art characteristics for integrated circuits (IC), i.e., high on/ off ratio (>10 7 ) and record drive current density (100 µA µm −1 ). [14,15] So far, a number of approaches have been developed to obtain TMDCs, including the micromechanical cleavage method [16] and liquid-phase exfoliation [17][18][19] due to the weak van der Waals interactions between the neighboring layers. Among them, chemical vapor deposition (CVD) has been widely demonstrated to be an effective technique to synthesize highquality TMDCs as well as their in-plane and vertical heterostructures by using different precursors, [20,21] such as the solid powders of MoO 3 , [22][23][24][25] MoO 3 solution, [26,27] MoCl 5 , [28] WO 3 , [29,30] WS 2 , WSe 2 , MoS 2 , and MoSe 2 [31][32][33] with the additional alkali metal halides as the growth promoters, [2,34] the gaseous chemical precursors including molybdenum hexacarbonyl (MHC), [4] as well as the liquid precursors like the solution of ammonium thiomolybdate (NH 4 ) 2 MoS 4 , [35,36] ammonium molybdate tetrahydrate (NH 4 ) 6 Mo 7 O 24 •4H 2 O and ammonium tungstate hydrate Chemical vapor deposition (CVD) has been widely used to synthesize highquality 2D transition-metal dichalcogenides (TMDCs) from different precursors. At present, quantitative control of the precursor with high precision and good repeatability is still challenging. Moreover, the process to synthesize TMDCs with designed patterns is complicated. Here, by using an industrial inkjet-printer, an in situ aqueous precursor with robust usage control at the picogram (10 −12 g) level is achieved, and by precisely tuning the inkjetprinting parameters, followed by a rapid heating process, large-area patterned TMDC films with centimeter size and good thickness controllability, as well as heterostructures of the TMDCs, are achieved facilely, and high-quality single-domain monolayer TMDCs with millimeter-size can be easily synthesized within 30 s (corresponding to a growth rate up to 36.4 µm s −1 ). The resulting monolayer MoS 2 and MoSe 2 exhibits excellent electronic properties with carrier mobility up to 21 and 54 cm 2 V −1 s −1 , respectively. The study paves a simple and robust way for the in situ ultrafast and patterned growth of high-quality TMDCs and heterostructures with promising industrialization prospects. Moreover, this ultrafast and green method can be easily used for synthesis of other 2D materials with slight modification.

Synthesis and Characterization of Metallic Janus MoSH Monolayer

“…Transport measurement of MoS 2 (Figures S8 and S9), MoSH (Figure S17), and MoSSe (Figure S10) was performed with back-gated field-effect transistors (FETs) as shown in Figure a and inset in Figure b. , Figure S8 shows the electrical properties of the initial MoS 2 monolayer with a good ohmic contact Figure S9 presents the metal–insulator transition (MIT) in a high quality monolayer MoS 2 device .…”

“…20,33 Figure S8 shows the electrical properties of the initial MoS 2 monolayer with a good ohmic contact. 34 Figure S9 presents the metal−insulator transition (MIT) in a high quality monolayer MoS 2 device. 20 In order to reduce the organic contaminations and the oxidation at the heating stage during the photolithography process, as well as to prevent the prolonged exposure to atmospheric air, 1,33 high-performance FET devices based on pristine MoS 2 (Figures S8 and S9) were made and tested first, and then the samples were loaded in the home-built ICP setup for hydrogen plasma treatment to form MoSH gradually.…”

Probing Electronic Properties of CVD Monolayer Hexagonal Boron Nitride by an Atomic Force Microscope

“…The monolayer h-BN nanoflakes were grown on the inner side of the Cu-foil enclosure by customized low-pressure chemical vapor deposition (LPCVD) (Wan et al, 2021) with the precursor of solid NH 3 -BH 3 since the growth of LPCVD is preferentially surface reaction limited and less affected by the geometry of the substrate or gas flow effect (Bhaviripudi et al, 2010). The synthesis of monolayer h-BN flakes was carried out in our CVD system (see Supplementary Figure S1A) which contains a split tube furnace with a fused quartz tube (OD: 50 mm) as shown in Figure 1A.…”

Photoinduced Multi‐Bit Nonvolatile Memory Based on a van der Waals Heterostructure with a 2D‐Perovskite Floating Gate

“…Furthermore, uncontrollable interface is detrimental to the retention time and operation speed of the memory device. 2D van der Waals (vdW) crystals manifest ultra-thin layered structure, highly anisotropic in-and outof-plane conductivity and superior carrier migration, [6] which are promising to solve the above problems. Over the past decade, 2D vdW atomic crystals, such as graphene, MoS 2 , ReS 2 , etc., are widely used as the composed elements in FGNVM, [7][8][9][10][11] and extended device structures are proposed to improve the performance.…”