Patterned Growth of Transition Metal Dichalcogenide Monolayers and Multilayers for Electronic and Optoelectronic Device Applications.

Abstract

A simple, large area, and cost-effective soft lithographic method is presented for the patterned growth of high-quality 2D transition metal dichalcogenides (TMDs). Initially, a liquid precursor (Na2 MoO4 in an aqueous solution) is patterned on the growth substrate using the micromolding in capillaries technique. Subsequently, a chemical vapor deposition step is employed to convert the precursor patterns to monolayer, few layers, or bulk TMDs, depending on the precursor concentration. The grown patterns are characterized using optical microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and photoluminescence spectroscopy to reveal their morphological, chemical, and optical characteristics. Additionally, electronic and optoelectronic devices are realized using the patterned TMDs and tested for their applicability in field effect transistors and photodetectors. The photodetectors made of MoS2 line patterns show a very high responsivity of 7674 A W-1 and external quantum efficiency of 1.49 × 106 %. Furthermore, the multiple grain boundaries present in patterned TMDs enable the fabrication of memtransistor devices. The patterning technique presented here may be applied to many other TMDs and related heterostructures, potentially advancing the fabrication of TMDs-based device arrays.