Chemically driven isothermal closed space vapor transport of MoO$_2$: thin films, flakes and in-situ tellurization

TL;DR

This paper introduces a novel, low-temperature, closed space vapor transport method for growing pure MoO2 films and flakes, enabling in-situ transformation into MoTe2, a transition metal dichalcogenide.

Contribution

The study presents a new CSVT-based technique that does not require a temperature gradient and allows in-situ tellurization of MoO2, advancing thin film fabrication methods.

Findings

Successful growth of pure MoO2 in a reductive atmosphere.

In-situ transformation of MoO2 into MoTe2.

Low-temperature process without a temperature gradient.

Abstract

A novel procedure, based in a closed space vapor transport (CSVT) configuration, has been devised to grow films or flakes of pure MoO2 in a reductive atmosphere, at relatively low temperature and using MoO3 as the source. In contrast with conventional CSVT technique, in the proposed method a temperature gradient is not required for the growth to take place, which occurs through an intermediate volatile transport species that is produced in the complex reduction reaction of MoO3. An added value of this simple method is the possibility of transforming the MoO2 into MoTe2, one of the most interesting members of the transition metal dichalcogenide family. This is achieved in a sequential process that includes the growth of Mo oxide and its (in-situ) tellurization in two consecutive steps.