Large scale growth of vertically standing MoS2 flakes on 2D nanosheet using organic promoter

A facile method was developed for chemical vapor deposition (CVD) growth of large-scale vertically oriented molybdenum disulfide nanoflakes on a basal MoS2 thin film (nu-MoS2 on MoS2-TF) utilizing a porphyrin-type organic promoter layer, which catalyzed the synthesis and allowed large scale growth of v-MoS2 on MoS2-TF. Here, the growing density of the vertical MoS2 flakes was manipulated by adjusting the growth temperature and the thickness of the organic promoter layers. The v-MoS2 on MoS2-TF is even transferrable to arbitrary flexible substrates using the wet-transfer method without inducing noticeable amount of defects. A thin-film transistor was fabricated to determine the electrical property of the v-MoS2 on MoS2-TF film. Significantly, the vertically grown MoS2 was also applicable as the catalyst for hydrogen evolution reaction, which demonstrated a decreased overpotential by 1/3 of those by horizontally grown MoS2 or other CVD-grown crystalline MoS2 thin films previously reported.