Formation of 2H and 1T/2H MoSe2 via thermal selenization of electrodeposited Mo thin films and nanowires

Abstract

Here, we present how thermal selenization can be used in tandem with electrodeposition to prepare MoSe₂-based materials. Mo precursors (thin films or nanowire arrays) were prepared via electrodeposition and thermally selenized at 500/600 °C for 2/3h. Scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used to determine the morphology, chemical and phase compositions of materials. The experimental results demonstrated changes in the morphology after selenization, like creation of circular grain domains in Mo films, and partial hollowing and coarsening of Mo nanowires. Selenization of both types of precursors resulted in phase-diverse MoSe₂ products: hexagonal (2H) phase for Mo films, and mixture of trigonal and hexagonal (1T/2H) phases in the case of Mo nanowires. EDS measurements revealed that the Se content in Mo-Se films varied from 4.6 to 26.5 at.%, while in Mo-Se nanowires, it ranged from 54.7 to 61.4 at.%, which indicates that thermal selenization was more effective when the precursor was in the form of nanowires. This study suggests the potential to control parameters in the thermal selenization process such as substrate selection, temperature, and duration to develop innovative MoSe₂-based electrodes for more efficient energy-related applications.