Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition.

Markus Rohdenburg,Petra Martinović,Charlene J Lobo,Petra Swiderek,Johannes E Fröch

doi:10.3390/mi11080769

Markus Rohdenburg, Petra Martinović + Show 3 more

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https://doi.org/10.3390/mi11080769

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Abstract

Ammonia (NH3)-assisted purification of deposits fabricated by focused electron beam-induced deposition (FEBID) has recently been proven successful for the removal of halide contaminations. Herein, we demonstrate the impact of combined NH3 and electron processing on FEBID deposits containing hydrocarbon contaminations that stem from anionic cyclopentadienyl-type ligands. For this purpose, we performed FEBID using bis(ethylcyclopentadienyl)ruthenium(II) as the precursor and subjected the resulting deposits to NH3 and electron processing, both in an environmental scanning electron microscope (ESEM) and in a surface science study under ultrahigh vacuum (UHV) conditions. The results provide evidence that nitrogen from NH3 is incorporated into the carbon content of the deposits which results in a covalent nitride material. This approach opens a perspective to combine the promising properties of carbon nitrides with respect to photocatalysis or nanosensing with the unique 3D nanoprinting capabilities of FEBID, enabling access to a novel class of tailored nanodevices.

Highlights

Nanoscale materials fabricated by focused electron beam-induced deposition (FEBID) drive the development of novel devices for a variety of applications [1,2,3]
The setup is equipped with a quadrupole mass spectrometer (QMS) residual gas analyzer (300 amu, Stanford Research Systems, Sunnyvale, CA, USA) with electron impact ionization at 70 eV, a commercial flood gun (SPECS FG 15/40, SPECS Surface Nano Analysis GmbH, Berlin, Germany) for electron irradiation in the range of E0 = 1–500 eV, an Auger electron spectrometer (STAIB DESA 100, STAIB INSTRUMENTS GmbH, Langenbach, Germany), and a sputter gun operated with Ar+ ions at a kinetic energy of 3 keV
Our present study provides evidence that combined NH3 and electron processing of deposits fabricated from the FEBID precursor (EtCp)2Ru yields deposits with Ru embedded in a material with the chemical composition of a carbon nitride (C3N4)

Summary

Introduction

Nanoscale materials fabricated by focused electron beam-induced deposition (FEBID) drive the development of novel devices for a variety of applications [1,2,3]. In FEBID, volatile precursor molecules that contain an element of the desired material are adsorbed on a surface and fragmented under a tightly focused electron beam. In this process, a solid deposit is formed, while volatile fragments desorb and are pumped away. As a successful and mild post-deposition purification process, electron irradiation in the presence of H2O vapor was recently brought forward This process was applied to deposits produced from the precursors trimethyl(methylcyclopentadienyl)-platinum(IV) (MeCpPtMe3) [6], tetrakis(trifluorophosphine)platinum(0) (Pt(PF3)4) [7], dimethyl(acetylacetonate) gold(III) (Me2Au(acac)) [8], and, more recently, from bis(ethylcyclopentadienyl)ruthenium(II) ((EtCp)2Ru) [9]. H2O was used under electron irradiation to etch away hexagonal boron nitride (hBN) for fabrication of silver nanowire–nitride heterostructures on surfaces [11]

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