High-Crystalline Monolayer Transition Metal Dichalcogenides Films for Wafer-Scale Electronics

Abstract

Chemical vapor deposition (CVD) using liquid-phase precursors has emerged as a viable technique for synthesizing uniform large-area transition metal dichalcogenide (TMD) thin films. However, the liquid-phase precursor-assisted growth process typically suffers from small-sized grains and unreacted transition metal precursor remainders, resulting in lower-quality TMDs. Moreover, synthesizing large-area TMD films with a monolayer thickness is also quite challenging. Herein, we successfully synthesized high-quality large-area monolayer molybdenum diselenide (MoSe2) with good uniformity via promoter-assisted liquid-phase CVD process using the transition metal-containing precursor homogeneously modified with an alkali metal halide. The formation of a reactive transition metal oxyhalide and reduction of the energy barrier of chalcogenization by the alkali metal promoted the growth rate of the TMDs along the in-plane direction, enabling the full coverage of the monolayer MoSe2 film with negligible few-layer regions. Note that the fully selenized monolayer MoSe2 with high crystallinity exhibited superior electrical transport characteristics compared with those reported in previous works using liquid-phase precursors. We further synthesized various other monolayer TMD films, including molybdenum disulfide, tungsten disulfide, and tungsten diselenide, to demonstrate the broad applicability of the proposed approach.

The Photodetectors Based on Lateral Monolayer MoS2/WS2 Heterojunctions

“…1 a, indicating two materials form at the interface. In addition, the frequency difference between the E 2g mode and A 1g mode of MoS 2 is 19.8 cm −1 , suggesting monolayer one [ 30 , 38 , 39 ]. When considering WS 2 , the peak intensity ratio of longitudinal acoustic mode (2LA) [ 40 ] at 352 cm −1 to A 1g mode, i.e.…”

Two‐Dimensional Metal Chalcogenide Heterostructures: Designed Growth and Emerging Novel Applications

“…In the growth of 2DMCHs, SiO 2 /Si, mica, and sapphire wafers are the most commonly used substrates. [ 1,2,103,158 ] With continuing development, metal substrates are increasingly employed as substrates due to their S‐resistant properties and the solubility of reaction atoms to synthesize uniform, high‐quality, and large‐domain 2DMCHs. [ 135,159–161 ] Besides, 2D materials have also been used as a growth substrate due to their atomically flat and dangling‐bond‐free surfaces, offering ultrathin and scalable 2DMCHs.…”

High-Performance Photodetectors Based on Lateral Monolayer MoS2/WS2 Heterojunctions

“…The suggesting monolayer one [26,34,35]. When considering WS2, the peak intensity ratio of longitudinal acoustic mode (2LA) [36] at 352 cm -1 to A1g mode, i.e.…”