A combined gas-phase dissociative ionization, dissociative electron attachment and deposition study on the potential FEBID precursor [Au(CH3)2Cl]2

Motivated by the potential of focused-electron-beam-induced deposition (FEBID) in the fabrication of functional gold nanostruc-tures for application in plasmonic and detector technology, we conducted a comprehensive study on [Au(CH3)2Cl]2 as a potential precursor for such depositions. Fundamental electron-induced dissociation processes were studied under single collision conditions, and the composition and morphology of FEBID deposits fabricated in an ultrahigh-vacuum (UHV) chamber were explored on dif-ferent surfaces and at varied beam currents. In the gas phase, dissociative ionization was found to lead to significant carbon loss from this precursor, and about 50% of the chlorine was on average removed per dissociative ionization incident. On the other hand, in dissociative electron attachment, no chlorine was removed from the parent molecule. Contrary to these observations, FEBID in the UHV setup was found to yield a quantitative loss and desorption of the chlorine from the deposits, an effect that we attribute to electron-induced secondary and tertiary reactions in the deposition process. We find this precursor to be stable at ambient condi-tions and to have sufficient vapor pressure to be suitable for use in HV instruments. More importantly, in the UHV setup, FEBID with [Au(CH3)2Cl]2 yielded deposits with high gold content, ranging from 45 to 61 atom % depending on the beam current and on the cleanliness of the substrates surface.

Automated summary

Motivated by the potential application of focused-electron-beam-induced deposition (FEBID) in plasmonic and detector technology, this study comprehensively investigated [Au(CH3)2Cl]2 as a potential precursor. The dissociation processes and composition of FEBID deposits were studied under single collision conditions and in an ultrahigh-vacuum (UHV) chamber. The results showed significant carbon loss and chlorine removal in the gas phase, while quantitative chlorine loss and desorption were observed in the UHV setup. The precursor was found stable at ambient conditions and suitable for use in HV instruments, producing deposits with high gold content.