Surface‐Functionalization‐Mediated Direct Transfer of Molybdenum Disulfide for Large‐Area Flexible Devices

Abstract

The transfer of synthesized large‐area 2D materials to arbitrary substrates is expected to be a vital step for the development of flexible device fabrication processes. The currently used hazardous acid‐based wet chemical etching process for transferring large‐area MoS2 films is deemed to be unsuitable because it significantly degrades the material and damages growth substrates. Surface energy‐assisted water‐based transfer processes do not require corrosive chemicals during the transfer process; however, the concept is not investigated at the wafer scale due to a lack of both optimization and in‐depth understanding. In this study, a wafer‐scale water‐assisted transfer process for metal–organic chemical vapor‐deposited MoS2 films based on the hydrofluoric acid treatment of a SiO2 surface before the growth is demonstrated. Such surface treatment enhances the strongly adhering silanol groups, which allows the direct transfer of large‐area, continuous, and defect‐free MoS2 films; it also facilitates the reuse of growth substrate. The developed transfer method allows direct fabrication of flexible devices without the need for a polymeric supporting layer. It is believed that the proposed method can be an alternative defect‐ and residue‐free transfer method for the development of MoS2‐based next‐generation flexible devices.

High‐Throughput Growth of Wafer‐Scale Monolayer Transition Metal Dichalcogenide via Vertical Ostwald Ripening

“…The FETs shown in Figure 4d Figure 4g. Although pulsed-MOCVD-grown MoS 2 has a relatively small grain size, its device performance is comparable to that of other CVDgrown MoS 2 even with a larger grain size [16,17,23,24,[34][35][36] due to the damage-free transfer method. Notably, the µ FE can be further improved by optimizing the film quality and device structure including the contact between metal and MoS 2 .…”

“…[15] Regarding the production of wafer-scale films, metal-organic chemical vapor deposition (MOCVD) based on gas-phase precursors is particularly promising, owing to the uniform and precisely controlled supply of precursors over the entire substrate. [16,17] For preparing wafer-scale monolayers by MOCVD, secondary nucleation on the pre-synthesized TMDs should be suppressed during growth. This has been successfully achieved by growing TMDs under an extremely low partial pressure of sources to approach the adsorption/desorption equilibrium.…”

“…This has been successfully achieved by growing TMDs under an extremely low partial pressure of sources to approach the adsorption/desorption equilibrium. [16,17] However, under this condition, the growth rate is extremely low, that is, several hours are required for the growth of wafer-scale monolayer TMDs. To improve the growth rate in the layer-by-layer growth mode, secondary nucleation should be controlled even under high partial pressure of the sources.…”

Recent Advances in Tactile Sensing Technology

“…Transition metal dichalcogenides (TMDs) such as MoS 2 are attracting interest, as such materials possess comparable or superior characteristics to graphene, including good optical transparency, outstanding mechanical flexibility, and good electrical properties [ 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 ]. In particular, ultrathin MoS 2 semiconductors with high sensitivity and a tunable band gap are strong candidate materials that can be used to produce advanced tactile sensors with good conformability [ 18 ].…”

From Silver Nanoflakes to Silver Nanonets: An Effective Trade-Off between Conductivity and Stretchability of Flexible Electrodes

“…Flexible printed electronics aim to minimize material waste and production costs, which was considered as an effective way to reduce carbon dioxide emissions during manufacturing [1,2]. With the development of nanomaterials and nanotechnology, various kinds of printing pastes ranging from conductors, insulators, and semiconductors comprised of nanostructures have been developed and utilized for solar cells [3], touch screens [4], transistors [5], sensors [6,7], and elastic/flexible devices [8,9]. Additionally, flexibility and stretchable properties are considered as the key parameters of flexible devices [10].…”