Chemically driven isothermal closed space vapor transport of MoO2: thin films, flakes and in situ tellurization

Abstract

A novel procedure, based on a closed space vapor transport (CSVT) configuration, has been devised to grow films or flakes of pure MoO₂ in a reductive atmosphere, at a relatively low temperature and using MoO₃ as the source. In contrast to the 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.