High‐performance electronics and optoelectronics of monolayer tungsten diselenide full film from pre‐seeding strategy

Abstract

Tungsten diselenide (WSe2) possesses extraordinary electronic properties for applications in electronics, optoelectronics, and emerging exciton physics. The synthesis of monolayer WSe2 film is of topmost for device arrays and integrated circuits. The monolayer WSe2 film has yet been reported by thermal chemical vapor deposition (CVD) approach, and the nucleation mechanism remains unclear. Here, we report a pre‐seeding strategy for finely regulating the nuclei density at an early stage and achieving a fully covered film after chemical vapor deposition growth. The underlying mechanism is heterogeneous nucleation from the pre‐seeding tungsten oxide nanoparticles. At first, we optimized the precursor concentration for pre‐seeding. Besides, we confirmed the superiority of the pre‐seeding method, compared with three types of substrate pretreatments, including nontreatment, sonication in an organic solvent, and oxygen plasma. Eventually, the high‐quality synthetic WSe2 monolayer film exhibits excellent device performance in field‐effect transistors and photodetectors. We extracted thermodynamic activation energy from the nucleation and growth data. Our results may shed light on the wafer‐scale production of homogeneous monolayer films of WSe2, other 2D materials, and their van der Waals heterostructures.

Revealing and Controlling Energy Barriers and Valleys at Grain Boundaries in Ultrathin Organic Films

“…We have focused our work on a prototypical perylene‐diimide semiconductor, an organic dye which is often used in optoelectronic devices, but the general concept of valleys and barriers and their presence in thin films may also hold for other materials used as transport layers in OLEDs, OPV, and OFETs. In addition, the insights from this work may prove useful for researchers investigating charge transport in other optoelectronic materials systems such as perovskites, [ 57 ] metal oxides, [ 58 ] and transition metal dichalcogenides, [ 59,60 ] where grain boundaries might occur and lead to loss in transport or energy transformation processes.…”

Research progress in the synthesis and biological application of quantum dots

“…In recent years, transition metal disulfide materials have made great progress in biomedicine, physical chemistry, electronics and optoelectronics 137,138 due to their special structure and good properties. Among all transition metal dichalcogenide compounds (TMDCs), the most famous is molybdenum disulfide (MoS 2 ), which has great application prospects in various biomedical applications because of its higher surface volume ratio, more edge sites and water solubility.…”

A mini-review focusing on ambient-pressure chemical vapor deposition (AP-CVD) based synthesis of layered transition metal selenides for energy storage applications

“…For example, the thermodynamically stable phase of WSe 2 is 2H, which is a semiconducting phase. 11,48 However, this material can exhibit a metallic 1T phase under certain conditions, e.g. , due to alkali metal intercalation or solvothermal synthesis conditions.…”