Preparation of 2D MoS₂ Atomic Layers from Precursor Solution Formulation and Simple Thermal Annealing for Patterned MoS₂ TFT

Due to unique properties such as high carrier mobility and innate band gap, two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted great attention in optoelectronic and nanoelectronic fields as well. Among those atomically thin materials, molybdenum disulfide (MoS₂) has become an emerge candidate because of the indirect to direct band gap transition in monolayer limit. Chemical vapor deposition (CVD) with sulfur gas is the most popular method for synthesizing large- scale 2D materials with high quality. Various MoS₂ can be obtained from this meth[od using various precursors with different properties, process temperatures, and substrate materials. Solution process methods show advantages for preparing films with large size, high throughput, low cost, thickness control, and an environmentally friendly process.<br/>We developed a Mo-based solution formualtion for solution-processed synthesis of MoS₂ with large-scale and uniformity. The precursor solution can be converted to atomic layer films using simple thrmal annealing without using chemical vapour process. A MoS₂ thin film was prepared by a simple jet printing and one-step annealing method. Three atomic layers of MoS₂ were obtained with 0.0125 M of precursor solution, which was confirmed by STEM. he atomic layers of the synthesized MoS₂ were identified as 2 layers for 0.0070 M, 3 layers for 0.0125 M, and 5 layers for 0.0250 M of MoS₂ solution by STEM-FIB. A printed MoS₂ TFT shows a high current ratio of approximately 10⁶, a good mobility of 27.5 cm²V^-1s^-1, a threshold voltage of 1.76 V, and a subthreshold slope of 1.32 Vdec^-1.