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S. Barth, F. Biegger, F. Porrati, M. Hanefeld, P. Weirich, M. Huth, R. Kumar, R. Bjornsson, O. Ingolfsson:
"Synthesis and characterization of heterometallic carbonyls for focused electron beam induced deposition";
Talk: FEBIP 2016, Wien; 2016-07-04 - 2016-07-08; in: "FEBIP 2016", (2016), 90.

Homometallic carbonyls are widely used precursors for nanomaterial synthesis in gas phase processes and in liquids to form metallic coatings or nanostructures. Many of these carbonyls are commercially available and therefore they have been extensively studied. In particular, the deposition of metallic nanostructures by focused electron beam deposition (FEBID) using these homometallic carbonyls has been investigated and optimized in the recent past.[1-3] To date, deposition of more than one metal is limited to the co-feeding of multiple gaseous sources despite synthetic methods to prepare hetero-metallic carbonyls.
As a proof of concept, HFeCo3(CO)12 was prepared from the homometallic Fe(CO)5 and Co2(CO)8 in a slightly modified procedure described by Chini et al..[4] The heterometallic carbonyl was recrystallized to obtain suitable single crystals, which were used to solve the crystal structure for a simulation of the powder XRD pattern to yield information about a larger sample size. In addition, geometrical parameters from single crystal X-ray diffraction are compared with calculated values from density functional theory for the neutral ground state of this transition metal cluster.[5] Starting from this ground state, the threshold values and the corresponding anions could be calculated for sequential CO loss. These data can help to understand the deposition process in FEBID better, since dissociative electron attachment upon interaction with low energy electrons is one important decomposition path in electron-induced deposition.
HFeCo3(CO)12 can be sublimed at temperatures below 60 °C (10-2 mbar) and decomposes to a smooth metallic film in a low pressure chemical vapour deposition with an expected metal ratio of 1:3.02 (Fe:Co) according to EDX analysis. This heterometallic carbonyl precursor was used in a FEBID process yielding deposits with high metal contents (> 80%) after optimisation of the process parameters.[6] The injector was heated to in order to obtain a sufficient vapour pressure for the deposition experiments. The 1:3 Fe:Co ratio of the heterometallic carbonyl was retained during the FEBIP process and the deposits were investigated in terms of their magnetic and electrical properties. This contribution also points out differences to the structurally related H2FeRu3(CO)13 system.