Deposition of Mo Oxide and Metallic Mo Films by ChemicalVapor Transport of MoO_3(OH)_2

摘要

Molybdenum oxides have attracted interest as gas sensing, catalytic, photochromic, and electrochromic materials. Molybdenumcoatings are currently applied to materials for friction and wear control over a wide temperature range; they are also resistant tocorrosion and chemicals. In this study, a new technique for deposition of MoO_2 and metallic Mo, through the chemical vaportransport (CVT) of MoO_3(OH)_2 during hydrogen reduction of a MoO_3 powder, is presented. MoO_2 and metallic Mo aredeposited in two temperature ranges during hydrogen reduction, namely, MoO_3→MoO_2 and MoO_2→Mo, respectively. TheMoO_2 film is directly deposited by using volatile MoO3(OH)_2 gas formed during the hydrogen reduction of MoO_3 to MoO_2 atthe lower temperature, while metallic Mo film is obtained by simultaneous hydrogen reduction of deposited MoO_2 at the highertemperature.