Effects of Mo films prepared via different sputtering conditions on the formation of MoSe2 during selenization

The effects of Mo films prepared via various sputtering conditions on the formation of MoSe2 during selenization were investigated. After selenization treatment, the morphology of Mo films changed from pyramidal-like grains to round grains due to the formation of MoSe2, and the sheet resistance increased. The sheet resistance of the selenized Mo films was increased with the increase in the selenization temperature because of the raised amount of formed MoSe2. As the sputtering power for preparing Mo films was increased from 100 W to 250 W, an increase in the grain size of Mo films was observed. The enlarged grains of Mo films resulted in a small amount of grain boundaries, thereby reducing the contact area between Mo films and selenium vapor during the selenization process. The conversion ratio of MoSe2 calculated according to the increase in the film thickness significantly decreased as the sputtering power was increased. It is indicated that increasing the sputtering power for preparing Mo films significantly reduced the reactivity of Mo films with selenium and suppressed the formation of MoSe2. (C) 2018 Elsevier B.V. All rights reserved.