Short Term Scientific Mission: Exploration of Molybdenum oxide deposition by using novel Mo precursor

Scientific content of the collaboration: 

The collaboration between Laboratory of Inorganic Chemistry – University of Helsinki, Finland, and CNR-MDM-IMM, Italy, had the aim to develop  a novel ALD recipe for thin film MoO3 deposition by using a novel molybdenum b-diketonate type precursor.

The growth of Molybdenum oxide by atomic layer deposition has been scarcely explored in literature [1], despite the high interest on this material as thin films for hot topics such as gas sensors [2] and lithium ion batteries [3].
Interestingly, Mo oxide can be utilized as a precursor for the growth of Mo-based dichalcogenides such as MoS2 that recently attracts a tremendous interest for its remarkable properties when it is reduced to single or few layers [4]. Since ALD is naturally suited to results in a highly conformal film, the ALD of MoO3 films can overcome the above-mentioned constraints after carefully developing an appropriate process recipe. The recipes reported in literature are related exclusively to the use of molybdenum hexacarbonyl Mo(CO)6 as a precursor in combination with ozone or water. In these cases, the use of metal carbonyl is limited in a narrow temperature window due to its limited thermal stability at high temperature and low reactivity at low temperature [1]. Other Mo precursor classes, i.e. halides or alkoxides, have not been experimented or even synthesized.

[1] M. Diskus, et al., Dalton Trans., 41, (2012),2439; M. Diskus,  et al., J. Vac. Sci. Technol. A, 30(1), (2012), 01A107-1.
[2] D. E. Diaz-Droguett and V. M. Fuenzalida, Mater. Chem. Phys. 126, 82 (2011).
[3] H. Ohtsuka and Y. Sakurai, Solid State Ionics, 144, (2001), 59.
[4] Y.-H. Lee,  et al., Adv. Mater. 24, (2012), 2320.

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